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Klinische Studien zur Endodontie mit dem Dental-Laser

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Endo, Clean / Disinfect DOI URL  Abad-Gallegos, M., Arnabat-Dominguez, J., Espana-Tost, A., Berini-Aytes, L. and Gay-Escoda, C. In vitro evaluation of the temperature increment at the external root surface after Er,Cr:YSGG laser irradiation of the root canal Medicina Oral, Patologia Oral y Cirugia Bucal
Vol. 14(12) 
2009 rank1
Abstract: OBJECTIVES: A study was made to determine the temperature increment at the dental root surface following Er,Cr:YSGG laser irradiation of the root canal. DESIGN: Human canines and incisors previously instrumented to K file number ISO 30 were used. Irradiation was carried out with glass fiber endodontic tips measuring 200 mm in diameter and especially designed for insertion in the root canal. The teeth were irradiated at 1 and 2 W for 30 seconds, without water spraying or air, and applying a continuous circular movement (approximately 2 mm/sec.) in the apico-coronal direction. RESULTS: At the 1 W power setting, the mean temperature increment was 3.84 degrees C versus 5.01 degrees C at 2 W. In all cases the difference in mean value obtained after irradiation versus the mean baseline temperature proved statistically significant (p<0.05). CONCLUSIONS: Application of the Er,Cr:YSGG laser gives rise to a statistically significant temperature increment at the external root surface, though this increment is probably clinically irrelevant, since it would appear to damage the tissues (periodontal ligament and alveolar bone) in proximity to the treated tooth.
Endo, Clean / Disinfect DOI URL  Al-Karadaghi, T.S., Franzen, R., Jawad, H.A. and Gutknecht, N. Investigations of radicular dentin permeability and ultrastructural changes after irradiation with Er,Cr:YSGG laser and dual wavelength (2780 and 940 nm) laser Lasers in Medical Science
Vol. 30(8), pp. 2115-2121 
2015 rank5
Abstract: The aim of this study was to assess the effectiveness of dual wavelength (2780 nm Er,Cr:YSGG, 940 nm diode) laser in elimination of smear layer comparing it with Er,Cr:YSGG laser in terms of radicular dentin permeability and ultrastructural changes of root canal walls. Fifty-one sound single-rooted extracted teeth were instrumented up to size F4 and divided into three groups: group Co, non-irradiated samples; group A, irradiated with Er,Cr:YSGG laser; group B, irradiated with the dual wavelength laser. Afterward, the roots were made externally impermeable, filled with 2 % methylene blue dye, divided horizontally into three segments reflecting the cervical, middle, and apical thirds then examined under microscope. Using analytical software, the root section area and dye penetration area were measured, and then, the percentage of net dye penetration area was calculated. Additionally, scanning electron microscope investigations were accomplished. Analysis of variance (ANOVA) showed significant differences between all groups over the three root thirds. Dye permeation in dual wavelength laser group was significantly higher over the whole root length: cervical, middle, and apical compared to Er,Cr:YSGG laser group and non-irradiated samples (p < 0.001). Scanning electron micrographs of dual wavelength irradiated samples showed a distinctive removal of smear layer with preservation of the annular structure of dentinal tubules. Er,Cr:YSGG laser root canal irradiation produced uneven removal of smear layer, in efficient cleanliness especially in the apical third. There was no sign of melting and carbonization. Within the studied parameters, root canal irradiation with dual wavelength laser increased dentin permeability.
Endo, Clean / Disinfect DOI URL  Al-Karadaghi, T.S., Gutknecht, N., Jawad, H.A., Vanweersch, L. and Franzen, R. Evaluation of Temperature Elevation During Root Canal Treatment with Dual Wavelength Laser: 2780 nm Er,Cr:YSGG and 940 nm Diode. Photomedicine and laser surgery
Vol. 33(9), pp. 460-6 
2015 rank5
Abstract: OBJECTIVE: The purpose of this study was to evaluate the effects of dual wavelength (2780 nm Er,Cr:YSGG and 940 nm diode) laser with radial firing tip (RFT) on the external root surface and sub-surfaces, in terms of temperature changes during laser-assisted root canal treatment.nnBACKGROUND DATA: A significant factor that may limit the use of lasers in endodontics is the possible thermal injury to tooth supporting structures.nnMATERIALS AND METHODS: A total of 50 sound single-rooted extracted teeth were divided randomly into two groups (n = 25). Group A, irradiated with Er,Cr:YSGG laser at 1.06 W, 50 Hz, and 50 μs was a control group, and group B was irradiated with dual wavelength of Er,Cr:YSGG laser with the same settings as group A and a diode laser of 0.51 W at 4 ms and 10 ms pulse duration. K-type thermocouples were used to record temperature changes at the cervical, middle, and apical root thirds, on root surfaces and sub-surfaces, arising from delivery of laser energy through RFT.n Temperature elevation in group B was significantly higher in the middle and apical thirds of the prepared samples than in group A (p < 0.0001). Group B presented a mean temperature elevation of 5.07°C on the apical surface region corresponding to a 1.48 mm dentin thickness, whereas a mean temperature increase of 7.72°C was recorded corresponding to dentin thickness of 0.95 mm.n Within the studied parameters, the dual wavelength laser did not result in adverse thermal changes on the external root surface in vitro.
Endo, Clean / Disinfect URL  Al-Mafrachi, R., Awazli, L. and Al-maliky, M. Investigation of the Effect of Er:Cr:Ysgg Laser 2780 nm in Comparison with xp-Endo Finisher on Root Canal Dentin Permeability and Smear Layer Removal : An In Vitro Study Dental Health: Current Research
Vol. 4(1), pp. 1-5 
2018 rank4
Abstract: The aim of this study was to assess the effect of Er:Cr:YSGG 2780nm laser in comparison with Xp-endo Finisher in elimination of smear layer in terms of root canal dentin permeability and SEM analysis. Method: twenty-eight single-rooted extracted lower premolars were instrumented up to size X4 (protaper Next, Dentsaply) and divided into two groups according to the irrigation system, first group activated by Xp-endo Finisher and second one by Er:Cr:YSGG laser 2780 nm, pulsed mode, 1.25 W. Afterward, the roots were made externally impermeable, filled with 2%methylene blue dye, divided horizontally into three segments representing the apical, middle, and coronal thirds then examined under stereo- microscope. Using analytical software, the root section area and dye penetration area were measured, and then, the percentage of net dye penetration area was calculated. Moreover, scanning electron microscope investigations were accomplished. Results The non-parametric Mann-Whitney U test was done and showed a highly significant difference between the two experimental groups over the three root thirds. Dye penetration in Erbium laser group was significantly higher over the whole root length compared to other group. Scanning electron micrographs of Erbium laser group showed a distinctive removal of smear layer with preservation of the annular structure of dentinal tubules, while Xp-endo finisher group result in uneven removal of smear layer, and the dentinal tubules appear in sickle shape which indicate that they are partially opens especially in the apical third. Keywords
Endo, Clean / Disinfect DOI URL  Altundasar, E., Özçelik, B., Cehreli, Z.C. and Matsumoto, K. Ultramorphological and Histochemical Changes After Er,Cr:YSGG Laser Irradiation and Two Different Irrigation Regimes Journal of Endodontics
Vol. 32(5), pp. 465-468 
2006 rank3
Abstract: The purpose of this study was to evaluate the ultramorphological and chemical changes in Er,Cr:YSGG laser-treated radicular dentin in comparison with two different irrigation regimes. Extracted human premolars were assigned into three experimental groups. Group 1: After each file size, root canals were irrigated with 5.25% NaOCL, followed by a final irrigation with 5.25% NaOCL. Group 2: At each file size, biomechanical preparation was performed in conjunction with Rc-Prep, followed by 5.25% NaOCL irrigation; and 5.25% NaOCL for the final flush. Group 3: 5.25% NaOCL was used after each file size, followed by Er,Cr:YSGG laser irradiation; and a final flush with 5.25% NaOCL. Scanning electron microscopic (SEM) evaluations revealed failure of smear removal in NaOCL-irrigated specimens. RC-Prep + NaOCL-treated dentin revealed moderate-to-total presence of the smear layer with distinct areas of exposed collagen. Er,Cr:YSGG laser irradiation of radicular dentin also resulted in partial or total removal of the smear associated with a few small regions of thermal injury, including carbonization and partial melting. Energy dispersive X-ray analysis (SEM-EDX) showed no significant difference between the Ca/P ratios of the test groups, suggesting absence of changes at the molecular level.
Endo DOI URL  Amižić, I.P., Miletić, I., Ionescu, A., Brambilla, E., Gabrić, D. and Baraba, A. Influence of Laser Activated Irrigation with Erbium Lasers on Bond Strength of Inidividually Formed Fiber Reinforced Composite Posts to Root Canal Dentin Acta Stomatologica Croatica
Vol. 50(4), pp. 321-328 
2016
Abstract: OBJECTIVE: The aim of this in vitro study was to investigate the effect of laser activated irrigation (LAI) using two erbium lasers on bond strength of individually formed fiber-reinforced composite (FRC) posts to root canal dentin. MATERIALS AND METHODS: Twenty-seven single-rooted human teeth were endodontically treated and after post space preparation divided into three groups (n=9 per group), according to the pre-treatment of post space preparation: 1) Conventional syringe irrigation (CSI) and saline; 2) Er.YAG photon-induced photoacoustic streaming (PIPS) technique and saline; 3) Er,Cr:YSGG activated irrigation with RFT2 tip. Two specimens from each group were used for SEM analysis. The remaining specimens (n=7 per group) received individually formed FRC post, everStick POST, luted with self-adhesive cement, G-CEM LinkAce. After cementation, the roots were perpendicularly sectioned into 1 mm thin sections and a push-out test was carried out (0.5 mm/min). The data were calculated as megapascals and were log transformed and statistically analysed using one-way ANOVA at the level of significance set at 5%. RESULTS: In the control group, the smear layer was still present. In the Er:YAG group, the smear layer was removed. In the Er,Cr:YSGG group, the smear layer was partially removed. The Er,Cr:YSGG group achieved the highest bond strength values, followed by the control group and then the Er:YAG group, but no statistically significant difference was found in bond strength values in the tested group of post space pretreatment (p=0.564). CONCLUSIONS: LAI using two erbium lasers, with PIPS or RFT2 tip, did not affect the bond strength of individually formed FRC posts to root canal dentin.
Endo, Apicoectomy DOI   Angiero, F., Benedicenti, S., Signore, A., Parker, S. and Crippa, R. Apicoectomies with the Erbium Laser: A Complementary Technique for Retrograde Endodontic Treatment Photomedicine and Laser Surgery
Vol. 29(12), pp. 845-849 
2011 rank3
Abstract: Objective: The purpose of this study was to evaluate the efficacy of erbium lasers for retrograde endodontic treatment, in terms of clinical outcome and therapeutic success. Background data: Apicoectomy with retrograde filling is a well-established surgical procedure to treat teeth affected by persistent periapical lesions. The apical root end is generally removed with burs, and the adjacent periapical tissue curetted, or alternatively treated with ultrasound or laser. Methods: Between 2000 and 2010, 65 apicoectomies were performed on necrotic teeth that presented apical lesions (29 men, 36 women). The lasers used in the study were the erbium:yttrium-aluminum-garnet (Er:YAG) laser, wavelength 2940 nm, and the erbium,chromium-doped:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser, wavelength 2780 nm. Results: Of the 65 teeth in the study, failure only occurred in 9 cases, manifesting after different times. The remaining patients, 86.15%, experienced no complications, and their treatment followed a positive course. Conclusions: Laser-assisted surgery increases the range of therapeutic approaches in the sphere of retrograde endodontic treatment. The results of this study show that the erbium laser, used for apicoectomy, results in a high success rate with considerable benefit in terms of clinical outcome and therapeutic success.
Clean / Disinfect, Endo DOI   Arnabat, J., Escribano, C., Fenosa, A., Vinuesa, T., Gay-Escoda, C., Berini, L. and Viñas, M. Bactericidal activity of erbium, chromium:yttrium-scandium-gallium-garnet laser in root canals Lasers in Medical Science
Vol. 25(6), pp. 805-810 
2010 rank5
Abstract: The aim of this study was to investigate the effectiveness of the erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser by measuring its bactericidal effect inside root canals experimentally colonized with Enterococcus faecalis. We also determined the optimal conditions for the Er,Cr:YSGG laser to achieve the maximal bactericidal effect. An Er,Cr:YSGG Waterlase laser was used, and its antimicrobial effect was compared with that of sodium hypochlorite (NaOCl) at various concentrations as widely used in clinics. This laser emits photons at a wavelength of 2.78 microm. It is a pulsed laser operating at 20 Hz (20 pulses/s). Significant differences between measurements in the different groups (P < 0.05) were observed, depending on time and power used. The use of NaOCl 5% was the most effective procedure, with NaOCl 0.5% being the least effective; however, laser treatment was as effective as NaOCl 5% when applied at 2 W for 60 s.
Clean / Disinfect, Endo URL  Asnaashari, M. and Safavi, N. Disinfection of contaminated canals by different laser wavelengths, while performing root canal therapy Journal of Lasers in Medical Sciences
Vol. 4(1), pp. 8-16 
2013 rank4
Abstract: Removal of smear layer and disinfection of canals are important objectives of teeth root canal cleaning. In order to achieve this purpose, rinsing substances, intra canal drugs as well as ultrasound are used. Today, use of laser to remove smear layer and to disinfect root canals has increasingly attracted the attentions. Till now different lasers such as CO2, Nd:YAG, Er:YAG, Er,Cr:YSGG have been used for debris and smear removal from the canals. Numerous studies have shown that Er:YAG is the most appropriate laser for intra canal debris and smear removal. In addition different laser wavelengths have been used directly or as an adjunctive to disinfect canals. Laser light can penetrate areas of canals where irrigating and disinfecting solutions cannot reach, like secondary canals and deep dentinal tubules and also can eliminate microorganisms. Different studies have confirmed the penetration of Nd:YAG laser in deep dentin and reduction of microorganisms penetration. But studies on comparison of antibacterial effects of Nd:YAG laser with sodium hypochlorite showed effectiveness of both, with a better effect for sodium hypochlorite. Studies performed in relation with anti-microbial effects of Diode laser with various parameters show that this laser can be effective in reducing intra canal bacterial count and penetration in the depth of 500 microns in dentin. In studies performed on Diode laser in combination with canal irrigating solutions such as sodium hypochlorite and oxygenated water better results were obtained. Although studies on disinfection by the Erbium laser family show that use of this laser alone can be effective in disinfecting canals, studies evaluating the disinfecting effects of this laser and different concentrations of sodium hypochlorite show that the latter alone is more effective in disinfecting canals. And better results were obtained when Erbium laser was used in combination with sodium hypochlorite irrigating solution in canals. Results of the aforementioned articles indicate that this laser is effective in combination with a rinsing solution such as sodium hypochlorite. Results from studies including several types of the different Er:YAG, Ho:YAG, Nd:YAG, Er,Cr:YSGG lasers in disinfecting canals showed that all wavelengths used in disinfection for different thicknesses of dentin were efficacious without damaging thermal effect. Considering that use of different lasers in canals can be accompanied with temperature increase which can sometimes lead to damages to teeth and surrounding tissues, thus the use of photochemical phenomenon for elimination of microorganisms have attracted attention of many researchers. Studies in this field imply the efficacy of this method in reducing canal bacterial count and recommend its use as an adjunctive after biomechanical preparation of canals. Results from performed studies show removal of intra canal debris and smear layer by different lasers and particularly the Erbium laser family. Furthermore various laser wavelengths, particularly of Diode and Nd:YAG lasers can be effective in reducing intra canal microbial count. Maximum effect is obtained when laser light is used in canals in combination with sodium hypochlorite irrigating substance in appropriate concentration. Therefore use of laser energy can improve success rate of root canal treatments.
Clean / Disinfect, Endo DOI   Blanken, J., De Moor, R.J.G., Meire, M. and Verdaasdonk, R. Laser induced explosive vapor and cavitation resulting in effective irrigation of the root canal. Part 1: A visualization study Lasers in Surgery and Medicine
Vol. 41(7), pp. 514-519 
2009 rank4
Abstract: BACKGROUND AND OBJECTIVES: Limited information exists regarding the induction of explosive vapor and cavitation bubbles in an endodontic rinsing solution. It is also not clear whether a fiber has to be moved in the irrigation solution or can be kept stationary. No information is available on safe power settings for the use of cavitation in the root canal. This study investigates the fluid movements and the mechanism of action caused by an Er,Cr:YSGG laser in a transparent root model. MATERIAL AND METHODS: Glass models with an artificial root canal (15 mm long, with a 0.06 taper and apical diameter of 400 microm) were used for visualization and registration with a high-speed imaging technique (resolution in the microsecond range) of the creation of explosive vapor bubbles with an Er,Cr:YSGG laser at pulse energies of 75, 125, and 250 mJ at 20 Hz using a 200 microm fiber (Z2 Endolase). Fluid movement was investigated by means of dyes and visualization of the explosive vapor bubbles, and as a function of pulse energy and distance of the fiber tip to the apex. RESULTS: The recordings in the glass model show the creation of expanding and imploding vapor bubbles with secondary cavitation effects. Dye is flushed out of the canal and replaced by surrounding fluid. It seems not necessary to move the fiber close to the apex. CONCLUSION: Imaging suggests that the working mechanism of an Er,Cr:YSGG laser in root canal treatment in an irrigation solution can be attributed to cavitation effects inducing high-speed fluid motion into and out the canal.
Endo URL  Blanken, J. and Verdaasdonk, R. Cavitation as a working mechanism of the Er,Cr:YSGG laser in endodontics: a visualization study J Oral Laser Appl
Vol. 7(2), pp. 97-106 
2007 rank3
Abstract: Purpose: The objective of this study was to obtain a better understanding of the working mechanism of the Er,Cr:YSGG laser in endodontics using specialized imaging techniques. Materials and Methods: Using a high-speed imaging setup, cavitation bubbles induced by Er,Cr:YSGG laser were visualized with high temporal and special resolution in a water environment and in glass models of root canals using silica tips of 200, 320, and 400 μm diameter. A thermal imaging technique was combined with thermocouples to measure the temperature increase in the canal wall. Results: In water, the cavitation bubbles were reproducible. The relationship between pulse energy and dimensions of the bubble is linear. However, the dynamics of cavitation bubbles in the root canal model is complex. The cavitation effects exist for a much longer period of time and there is a turbulent mixture with air or gas bubbles. Colored dyes show very fast fluid motion in and out of the canal during laser exposure. The temperature increase measured was only 5 to 10 degrees. Conclusion: Our imaging suggests that the working mechanism of an Er,Cr:YSGG laser in root canal treatment can be attributed to cavitation effects inducing high speed fluid motions into and out of the canal. This might effectively remove the smear layer and sterilize the canal wall. The thermal component is moderate.
Endo, Apicoectomy DOI   ÇalIşkan, M.K., Parlar, N.K., Oruçoǧlu, H. and AydIn, B. Apical microleakage of root-end cavities prepared by Er,Cr:YSGG laser Lasers in Medical Science
Vol. 25(1), pp. 145-150 
2010 rank2
Abstract: The aim of this study is to assess the apical microleakage of the composite filled root-end cavities prepared by an Erbium, Chromium: Yttrium-Scandium-Gallium-Garnet laser. Fifty-five maxillary incisor teeth were enlarged and filled. Following the apical resection, root-end cavities were prepared using conventional methods: either using a bur (n = 30) or an ultrasonic retrotip (n = 15). Root-end cavities of the 15 teeth in the bur group were finished with the laser at 3.5 W. All root-end cavities were filled using two-step self-etching primer and composite resin. After 4 months of storage, apical microleakage was measured by a fluid filtration method. Microleakage of composite filled root-end cavities that were prepared by Er,Cr:YSGG was significantly larger than those made by conventional methods (p < 0.05). In conclusion, using the Er,Cr:YSGG laser has no advantages over conventional root-end cavity preparation methods when a composite filling material is used to seal root-end cavities.
Endo, Apicoectomy DOI   Camargo Villela Berbert, F.L., De Faria-Júnior, N.B., Tanomaru-Filho, M., Guerreiro-Tanomaru, J.M., Bonetti-Filho, I., Leonardo, R.D.T. and Marcantonio, R.A.C. An in vitro evaluation of apicoectomies and retropreparations using different methods Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology and Endodontology
Vol. 110(4) 
2010 rank3
Abstract: Objectives: The aim of this study was to evaluate: 1) the apical root surface, gutta-percha interface, and preparation time of root-end resections made with burs, ultrasound, or laser; and 2) the thickness of surrounding dentin after laser or ultrasonic root-end cavity preparation. Study design: 1) Thirty root-filled teeth were resected as follows: Zekrya bur in group I, Chemical Vapor Deposition (CVD) ultrasonic tip (9.5107-8) in group II, and ErCr:YSGG (Waterlase) in group III. The preparation time was recorded. Replicas of the resected root-ends were examined under a scanning electron microscope (SEM). 2) Thirty root-filled teeth were submitted to apicectomies and root-end cavities were prepared by using: CVD (6.1107-6) ultrasonic retrotips (group IV), EMS (DT-060) ultrasonic retrotips (group V), and ErCr:YSGG laser tips (group VI). Replicas of the root apices were examined under a SEM. Results: There were no fissures or fractures on root-end surfaces. The bur produced the smoothest surface (P < .05). Group I had the lowest preparation time (P < .05). The best adaptation between the filling and the root canals walls was observed in group III, but it was not significantly different from group II (P < .05). No resected root-ends had cracks after preparation. Group VI showed the least minimum dentin thickness (P < .05). Conclusions: The 3 methods evaluated did not cause any injury to the root-end surface, but they harmed the apical adaptation. Laser tips removed more dentin than ultrasonic retrotips and should be used with care to avoid overpreparation. ?? 2010 Mosby, Inc.
Endo DOI URL  Cengiz, E. and Yilmaz, H.G. Efficacy of Erbium, Chromium-doped:Yttrium, Scandium, Gallium, and Garnet Laser Irradiation Combined with Resin-based Tricalcium Silicate and Calcium Hydroxide on Direct Pulp Capping: A Randomized Clinical Trial Journal of Endodontics
Vol. 42(3), pp. 1-5 
2015 rank5
Abstract: INTRODUCTION:
The purpose of this randomized clinical study was to evaluate the efficiency of erbium, chromium-doped:yttrium, scandium, gallium, and garnet (Er,Cr:YSGG) laser irradiation combined with a resin-based tricalcium silicate material and calcium hydroxide in direct pulp capping for a 6-month follow-up period.

METHODS:
A total of 60 teeth of 60 patients between the ages of 18 and 41 years were recruited for this study. Sixty permanent vital teeth without symptoms and radiographic changes were randomly assigned to the following 4 groups (n = 15): Gr CH, the exposed area was sealed with calcium hydroxide (CH) paste; Gr laser CH, the treated area was sealed with CH paste after Er,Cr:YSGG laser irradiation at an energy level of 0.5 W without water and with 45% air; Gr TheraCal, TheraCal LC (Bisco, Schaumburg, IL) was applied directly to the exposed pulp; and Gr Laser TheraCal, TheraCal LC was applied after irradiation with an Er,Cr:YSGG laser. At the 1-week and 1-, 3-, and 6-month recall examinations, the loss of vitality, spontaneous pain, reactions to thermal stimuli and percussion, and radiographic changes were considered as failure.

RESULTS:
The success rates in the CH and TheraCal groups were 73.3% and 66.6%, respectively. These rates did not reveal any significant difference. In both laser groups, success rates were 100%. The Er,Cr:YSGG laser-irradiated TheraCal and Er,Cr:YSGG laser-irradiated CH groups showed statistically higher success rates than the TheraCal and CH groups, respectively.

CONCLUSIONS:
Er,Cr:YSGG laser irradiation at 0.5 W without water combined with pulp capping agents can be recommended for direct pulp therapy.

Endo, Clean / Disinfect DOI   Chaudhry, S., Yadav, S., Talwar, S. and Verma, M. Effect of endo activator and Er,Cr:YSGG laser activation of Qmix, as final endodontic irrigant, on sealer penetration: A Confocal microscopic study Journal of Clinical and Experimental Dentistry
Vol. 9(2), pp. e218-e222 
2017 rank3
Abstract: BACKGROUND: Through chemomechanical debridement of the root canal is a primary requisite for successful endodontic therapy. Thus the aim of this study was to evaluate the effects of using QmiX alone, QmiX with EndoActivator and QmiX with Er,Cr:YSGG laser for final irrigation on sealer penetration into the dentinal tubules. MATERIAL AND METHODS: 75 extracted human mandibular premolar teeth were treated with sodium hypochlorite (NaOCl) irrigation. The samples were divided into 5 groups according to the final irrigation solution used: (1) 17% EDTA and 2.5% NaOCl, (2) QmiX (3) QmiX with Er,Cr:YSGG laser and (4) QmiX with EndoActivator (5) 2.5%NaOCl. All teeth were obturated using cold lateral condensation technique with gutta percha and AH 26 sealer (Dentsply; DeTrey,Konstanz, Germany) labeled with Rhodamine B dye. The teeth were sectioned at distances of 2 and 5 from root apex. Total percentage and maximum depth of sealer penetration were measured using confocal laser scanning microscopy. RESULTS: Results of one way Anova analysis showed that there was a significant difference in the percentage and depth of sealer penetration among all groups at 3 and 5 mm level sections (P < .05). Within the groups maximum sealer penetration was recorded for Er,Cr:YSGG laser activated group. Greater depth of sealer penetration was recorded at 5mm as compared to 3mm in all the groups. CONCLUSIONS: Activation of QMix using EndoActivator and Er,Cr:YSGG laser enhanced the sealer penetration at apical and middle third. Thus Er,Cr:YSGG laser and EndoActivator may act as an appropriate adjunct during chemomechanical preparation of the root canal. Key words:EndoActivator, Er,Cr:YSGG laser, Qmix, confocal microscopy, sealer penetration.
Clean / Disinfect DOI   Cheng, X., Guan, S., Lu, H., Zhao, C., Chen, X., Li, N., Bai, Q., Tian, Y. and Yu, Q. Evaluation of the bactericidal effect of Nd:YAG, Er:YAG, Er,Cr:YSGG laser radiation, and antimicrobial photodynamic therapy (aPDT) in experimentally infected root canals Lasers in Surgery and Medicine
Vol. 44(10), pp. 824-831 
2012 rank3
Abstract: BACKGROUND AND OBJECTIVE: In recent years, various laser systems have been introduced into the field of laser-assisted endodontic therapy. The aim of this study was to evaluate the bactericidal effect of Nd:YAG, Er:YAG, Er,Cr:YSGG laser radiation, and antimicrobial photodynamic therapy (aPDT) in experimentally infected root canals compared with standard endodontic treatment of 5.25% sodium hypochlorite (NaClO) irrigation.nnMATERIALS AND METHODS: Two hundred and twenty infected root canals from extracted human teeth (contaminated with Enterococcus faecalis ATCC 4083 for 4 weeks) were randomly divided into five experimental groups (Nd:YAG, Er:YAG + 5.25% NaClO + 0.9% normal saline + distilled water (Er:YAG/NaClO/NS/DW), Er:YAG + 0.9% normal saline + distilled water (Er:YAG/NS/DW), Er,Cr:YSGG, and aPDT) and two control groups (5.25% NaClO as positive control and 0.9% normal saline (NS) as negative control). The numbers of bacteria on the surface of root canal walls and at different depths inside dentinal tubules before and after treatment were analyzed by means of one-way analysis of variance (one-way ANOVA). The morphology of bacterial cells before and after treatment was examined by scanning electron microscopy (SEM).n After treatment, the bacterial reductions in the experimental groups and the positive control group were significantly greater than that of the negative control group (P < 0.001). However, only Er:YAG/NaClO/NS/DW group showed no bacterial growth (the bacterial reduction reached up to 100%) on the surface of root canal walls or at 100/200 µm inside the dentinal tubules.n All the laser radiation protocols tested, especially Er:YAG/NaClO/NS/DW, have effective bactericidal effect in experimentally infected root canals. Er:YAG/NaClO/NS/DW seems to be an ideal protocol for root canal disinfection during endodontic therapy.
Endo DOI   Christo, J.E., Zilm, P.S., Sullivan, T. and Cathro, P.R. Efficacy of low concentrations of sodium hypochlorite and low-powered Er,Cr: YSGG laser activated irrigation against an Enterococcus faecalis biofilm International Endodontic Journal
Vol. 49(3), pp. 279-286 
2016 rank3
Abstract: AimTo establish the antibacterial efficacy of low concentrations ofnsodium hypochlorite with and without Er,Cr:YSGG laser activation onnEnterococcus faecalis biofilms in extracted teeth.nMethodologyThe root canals of 96 decoronated single-rooted extractednhuman teeth were prepared to a size 40, 0.06 taper 1mm beyond the apex.nThey were mounted within a flow cell, which was sterilized beforenpumping a nutrient media through the root canals. The flow cell wasninoculated with E.faecalis (ATCC 700802) and cultivated for 4weeks. Theends were sealed, and the roots were then subjected to one of sixntreatment groups: group 1: syringe irrigation (SI) with saline (control)nusing a 27 -gauge Monoject needle 1mm from the apex for 2min; group 2:nas for group 1 but with 1% NaOCl; group 3: as for group 1 but with 4% group 4: 0.5% NaOCl irrigation for 15s followed byactivated irrigation (LAI) with four 15-s cycles replenishing thenirrigant between cycles; group 5: as for group 4 but with 1% NaOCl asnthe irrigant; group 6: as for group 4 but with 4% NaOCl as thenirrigant. Following treatment, teeth were crushed and viable bacterianwere quantitated by serial dilution and plating. The colony-forming unitnvalues were compared between groups using one-way anova andadjusted post hoc tests. A two-tailed P value of <0.05 wasnconsidered statistically significant.nResultsThe mean number of cells recovered from the 1% NaOCl SI groupnwas significantly higher than that from the 4% NaOCl LAI groupP=0.02).nConclusionWithin the limitations of this laboratory study, low-powered0.5W) Er,Cr:YSGG laser activation did not improve the antibacterialneffect of low concentrations of sodium hypochlorite.
Clean / Disinfect DOI URL  De Moor, R.J.G., Blanken, J., Meire, M. and Verdaasdonk, R. Laser induced explosive vapor and cavitation resulting in effective irrigation of the root canal. Part 2: Evaluation of the Efficacy Lasers in Surgery and Medicine
Vol. 41(7), pp. 514-519 
2009 rank5
Abstract: BACKGROUND AND OBJECTIVES: Limited information exists regarding the induction of explosive vapor and cavitation bubbles in an endodontic rinsing solution. It is also not clear whether a fiber has to be moved in the irrigation solution or can be kept stationary. No information is available on safe power settings for the use of cavitation in the root canal. This study investigates the fluid movements and the mechanism of action caused by an Er,Cr:YSGG laser in a transparent root model. MATERIAL AND METHODS: Glass models with an artificial root canal (15 mm long, with a 0.06 taper and apical diameter of 400 microm) were used for visualization and registration with a high-speed imaging technique (resolution in the microsecond range) of the creation of explosive vapor bubbles with an Er,Cr:YSGG laser at pulse energies of 75, 125, and 250 mJ at 20 Hz using a 200 microm fiber (Z2 Endolase). Fluid movement was investigated by means of dyes and visualization of the explosive vapor bubbles, and as a function of pulse energy and distance of the fiber tip to the apex. RESULTS: The recordings in the glass model show the creation of expanding and imploding vapor bubbles with secondary cavitation effects. Dye is flushed out of the canal and replaced by surrounding fluid. It seems not necessary to move the fiber close to the apex. CONCLUSION: Imaging suggests that the working mechanism of an Er,Cr:YSGG laser in root canal treatment in an irrigation solution can be attributed to cavitation effects inducing high-speed fluid motion into and out the canal.
Clean / Disinfect DOI URL  De Moor, R.J.G., Meire, M., Goharkhay, K., Moritz, A. and Vanobbergen, J. Efficacy of ultrasonic versus laser-activated irrigation to remove artificially placed dentin debris plugs Journal of Endodontics
Vol. 36(9), pp. 1580-1583 
2010 rank4
Abstract: Introduction: The study assessed the efficacy of laser activated irrigation (LAI) with Erbium: Yttrium Aluminum Garnet (Er:YAG) and Erbium Chromium: Yttrium Scandium Gallium Garnet (Er,Cr:YSGG) wavelengths as compared with passive ultrasonic irrigation (PUI). Previously proposed irrigation times were used for LAI (4 × 5 seconds) and the intermittent flush technique (3 × 20 seconds). Methods: We used a split root model with an artificial root canal wall groove. Roots were prepared to an apical size # 40 with ProFiles 0.06 (Dentsply Maillefer, Baillaigues, Switzerland). Five groups of 20 straight canine roots were evaluated as follows: Group 1: hand irrigation for 20 s with 2.5% NaOCI (Cl); Group 2: PUI performed once for 20 s with the #20 lrrisafe (Satelec Acteon group, Merignac, France) (PUI1); Group 3: PUI for 3 × 20 s with the Irrisafe (PUI 2); Group 4: LAI with the Er, Cr:YSGG laser and Z2 (200 μm) Endolase tip (Biolase, San Clemente, USA) at 75 mJ for 4 × 5 s (LAI 11); Group 5: LAI with the En: YAG laser (HoYa Versawave, Cortaboeuf, France) and a 200 /urn endodontic fiber at 75 mJ for 4 × 5 s (LAI 2). Images from the groove were taken before and after irrigation. The quantity of dentin debris in the groove after the experimental protocols was evaluated. Results: Statistically significant differences (p < 0.05) were found between Cl and all other groups and between PUI 1 and the other groups. Conclusion: LAI techniques using erbium lasers (Er:YAG or Er,Cr:YSGG) for 20 seconds (4 × 5 seconds) are as efficient as PUI with the intermittent flush technique (3 × 20 seconds). Copyright textcopyright 2010 American Association of Endodontists.
Clean / Disinfect DOI   Dewsnup, N., Pileggi, R., Haddix, J., Nair, U., Walker, C. and Varella, C.H. Comparison of Bacterial Reduction in Straight and Curved Canals Using Erbium, Chromium:Yttrium-Scandium-Gallium-Garnet Laser Treatment versus a Traditional Irrigation Technique With Sodium Hypochlorite Journal of Endodontics
Vol. 36(4), pp. 725-728 
2010 rank4
Abstract: Introduction: This study compared the reduction of Enterococcus faecalis in straight and curved canals using an erbium, chromium:yttrium-scandium-gallium-garnet laser and irrigation with 6.15% sodium hypochlorite (NaOCl). Methods: Fifty-five single-rooted extracted teeth were divided into straight and curved canal groups. The root lengths were standardized (14.0 mm) and NiTi instruments were used to prepare the canals to a size #40/0.06 taper. Irrigation was performed with 6.15% NaOCl and RCPrep (Premier Dental Products Co, Plymouth Meeting, PA) as lubricant. The smear layer was removed with 17% EDTA. The samples were sterilized, inoculated with E. faecalis, and incubated for 48 hours at 37° in a CO2 chamber. They were then divided into 7 groups: NaOCl in straight canals (NS); NaOCl in curved canals (NC); laser in straight canals (LS); laser in curved canals (LC); positive control straight canals (PCS); positive control curved canals (PCC); and negative control (NegC). Bacterial reduction was measured by counting the colony-forming units (CFUs) and determining the optical density. Results: Groups NS, NC, and LS exhibited bacterial growth in 1 out of 10 samples (10%). In group LC, three out of 10 samples (30%) showed bacterial growth. Kruskal-Wallis showed a statistically significant difference between all treatment groups and the positive controls (p < 0.001). Analysis of variance showed a statistical significant difference in optic density between experimental and positive controls. Conclusions: Traditional irrigation techniques using 6.15% NaOCl effectively eliminated all bacteria in straight and curved canals. Er,Cr:YSGG laser also effectively removed all bacteria from straight canals. However, in three curved canals, even though there were significant bacterial reductions, they failed to render canals completely free of bacteria. textcopyright 2010 American Association of Endodontists.
Clean / Disinfect URL  Eldeniz, A.U., Ozner, F., Hadimli, H.H. and Erganis, O. Bactericidal efficacy of Er,Cr:YSGG laser irradiation against e faecalis compared with NAOCl irrigation International Endodontic Journal
Vol. 40(2), pp. 112-9 
2007 rank4
Abstract: AIM:
To compare the efficacy of a standard NaOCl irrigation procedure with that of Er,Cr:YSGG laser irradiation in contaminated root canals having small and large apical foramina.
METHODOLOGY:
Forty root canals of extracted central incisor teeth with straight roots were chosen so that their apical foramina just permitted the tip of a size 20-K file to pass through. The canals were then enlarged with files to size 60 and randomly divided into four groups of 10 teeth each. The apical foramina of one group were widened further so that the tip of a size 45-K file could just pass through. After sterilization, all roots were inoculated with Enterococcus faecalis for 48 h at 37 degrees C. The first group was used as a control, the second group was irrigated with 3% NaOCl solution for 15 min, and the last two groups having different sizes of apical foramina were irradiated with the Er,Cr:YSGG laser at output power from 0.5 W, with 20% air and water levels. The disinfecting efficacy of the groups was tested by collecting dentine chips from the inner canal walls of the specimens and counting viable E. faecalis on Mueller-Hinton agar plates.
RESULTS:
The differences in the mean number of viable colonies between the control and laser groups were statistically significant (P < 0.05). The control specimens had the highest number of microorganisms (153 x 10(3) +/- 39 x 10(3)). Complete sterilization was achieved in the 3% NaOCl group. The mean colony forming units (CFU) values obtained after Er,Cr:YSGG laser irradiation were 6.6 x 10(3) CFU and 6.5 x 10(3) CFU in root canals having large and small apical foramina respectively.
CONCLUSION:
In teeth with straight roots the Er,Cr:YSGG laser reduced the viable microbial population in root canals with small and large apical foramina but did not eradicate all bacteria. Three percent NaOCl inhibited the growth of E. faecalis and effectively sterilized all root canals.
Clean / Disinfect DOI   Franzen, R., Esteves-Oliveira, M., Meister, J., Wallerang, A., Vanweersch, L., Lampert, F. and Gutknecht, N. Decontamination of deep dentin by means of erbium, chromium:yttrium- scandium-gallium-garnet laser irradiation Lasers in Medical Science
Vol. 24(1), pp. 75-80 
2009 rank5
Abstract: The aim of this in vitro study was to evaluate the depth of effectiveness of erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser irradiation on microorganism reduction. From human roots, dentin slices of 100 microm to 1,000 microm thickness were prepared. These specimens were sterilized and then inoculated with 1 microl of Enterococcus faecalis suspension. The backs of the specimens were then irradiated with Er,Cr:YSGG radiation at a pulse energy of 3.13 mJ, delivered at an incidence angle of 5 degrees to the dentin slice surface. A control group was left without irradiation. The remaining bacteria were collected in 1 ml sterilized NaCl solution, serially diluted and seeded in Columbia-Agar plates. Despite the low pulse energy of 3.13 mJ, the Er,Cr:YSGG laser irradiation resulted in significant bacterial reduction up to a dentin thickness of 500 microm (P < 0.05). Scanning electron microscopy (SEM) micrographs of the contaminated and irradiated surfaces showed the absence of a smear layer and opened dentinal tubules.
Clean / Disinfect DOI URL  Franzen, R., Rashidisangsary, B., Ozturan, S., Vanweersch, L. and Gutknecht, N. Intrapulpal temperature changes during root surface irradiation with dual-wavelength laser (2780 and 940 nm): in vitro study. Journal of biomedical optics
Vol. 20(1), pp. 18002 
2015 rank5
Abstract: The present study evaluated the intrapulpal thermal changes that occurred during the treatment of the root surfaces with a laser system emitting Er,Cr:YSGG 2780- and 940-nm diode laser irradiation in an alternating sequence. Thirty single-rooted human teeth were collected. The teeth were divided into three groups (n=10 each) and irradiated with Er,Cr:YSGG alone or combined with a 940-nm diode laser. To investigate the intrapulpal temperature changes, specimens were embedded in a resin block with a set of thermocouples introduced at different positions within the root canals. The first group was irradiated with only Er,Cr:YSGG (25 mJ, 50 Hz, 50  μs pulse duration, water and air spray); the second group was irradiated with Er,Cr:YSGG (same setting) and a 940-nm diode (2 W, chopped mode with 20% duty cycle); the third group was irradiated with Er,Cr:YSGG (same setting) and a diode (2 W, chopped mode with 50% duty cycle). During all irradiations, thermal changes were recorded in real time with thermocouples. While group 3 showed thermal rises on average of 1.68±0.98°C in the pulp chamber, groups 1 and 2 showed average temperature rises of <0.5°C. The combined laser emission of 2780 and 940 nm is a promising way for root surface debridement without inducing intrapulpal thermal damage when using an appropriate water/air spray. All measured temperatures were considerably below the critical value of 5.6°C.
Clean / Disinfect DOI   George, R., Meyers, I.A. and Walsh, L.J. Laser Activation of Endodontic Irrigants with Improved Conical Laser Fiber Tips for Removing Smear Layer in the Apical Third of the Root Canal Journal of Endodontics
Vol. 34(12), pp. 1524-1527 
2008 rank5
Abstract: With a tube etching process, conical-ended optical fibers for middle infrared lasers that have lateral emissions can be produced, a feature of benefit for delivering laser energy onto the root canal walls. This study examined the ability of these improved laser tips when Er:YAG and Er,Cr:YSGG lasers were used in root canals in which thick smear layers had been created intentionally to provide a challenge for the laser system. Smear layer was assessed from scanning electron microscopy images with an objective digital method. Lasing improved the action of ethylene diamine tetraacetic acid with cetavlon (EDTAC) in removing smear layer. Conical fibers performed better than plain fibers, but there was no difference in performance between the 2 laser systems when matched for all other parameters. These results provide a "proof of concept" for lateral emitting fibers for endodontic procedures and illustrate the novel contribution of lasing to the action of EDTAC in dissolving smear layer.
Clean / Disinfect DOI   George, R. and Walsh, L.J. Apical Extrusion of Root Canal Irrigants When Using Er:YAG and Er,Cr:YSGG Lasers with Optical Fibers: An In Vitro Dye Study Journal of Endodontics
Vol. 34(6), pp. 706-708 
2008 rank4
Abstract: Because of the potential for irritant reactions in the periapical region, irrigant solutions must be constrained within the root canal. We examined fluid extrusion beyond the apical constriction by pressure waves generated by pulsed middle infrared lasers using needles and Max-I-Probes (Dentsply) as controls. Both free-running pulsed Erbium: Yttrium Aluminum Garnet (Er:YAG) and Erbium, Chromium: Yttrium Scandium Gallium Garnet (Er,Cr:YSGG) lasers with bare or conical fiber tips at distances of 5 or 10 mm from the apex displaced fluid past the apex. Larger apical openings showed greater extrusion of fluid. The volume of extruded fluid was similar to conventional 25-G needles, but fluid was distributed further from the apex. Because pulsed lasers create pressure waves in irrigant fluids within the root canal, the potential for extrusion of fluid from the apex should be considered when assessing intracanal laser treatments in endodontics.
Clean / Disinfect DOI URL  George, R. and Walsh, L.J. Thermal effects from modified endodontic laser tips used in the apical third of root canals with erbium-doped yttrium aluminium garnet and erbium, chromium-doped yttrium scandium gallium garnet lasers. Photomedicine and laser surgery
Vol. 28(2), pp. 161-5 
2010 rank4
Abstract: OBJECTIVE: To evaluate the temperature changes occurring on the apical third of root surfaces when erbium-doped yttrium aluminium garnet (Er:YAG) and erbium, chromium-doped yttrium scandium gallium garnet (Er,Cr:YSGG) laser energy was delivered with a tube etched, laterally emitting conical tip and a conventional bare design optical fiber tip.nnBACKGROUND DATA: Thermal effects of root canal laser treatments on periodontal ligament cells and alveolar bone are of concern in terms of safety.nnMATERIALS AND METHODS: A total of 64 single-rooted extracted teeth were prepared 1 mm short of the working length using rotary nickel-titanium Pro-Taper files to an apical size corresponding to a F5 Pro-Taper instrument. A thermocouple located 2 mm from the apex was used to record temperature changes arising from delivery of laser energy through laterally emitting conical tips or plain tips, using an Er:YAG or Er,Cr:YSGG laser.n For the Er:YAG and Er,Cr:YSGG systems, conical fibers showed greater lateral emissions (452 + 69% and 443 + 64%) and corresponding lower forward emissions (48 + 5% and 49 + 5%) than conventional plain-fiber tips. All four combinations of laser system and fiber design elicited temperature increases less than 2.5 degrees C during lasing. The use of water irrigation attenuated completely the thermal effects of individual lasing cycles.n Laterally emitting conical fiber tips can be used safely under defined conditions for intracanal irradiation without harmful thermal effects on the periodontal apparatus.
Clean / Disinfect DOI   Gordon, W., Atabakhsh, V.a., Meza, F., Doms, a., Nissan, R., Rizoiu, I. and Stevens, R.H. The antimicrobial efficacy of the erbium, chromium:yttrium-scandium-gallium-garnet laser with radial emitting tips on root canal dentin walls infected with Enterococcus faecalis Journal of the American Dental Association (1939)
Vol. 138(7), pp. 992-1002 
2007 rank5
Abstract: BACKGROUND: The authors used an in vitro model to investigate the ability of an erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser with radial emitting tips to disinfect Enterococcus faecalis-infected dentin. MATERIALS AND METHODS: The in vitro infected-dentin model system consisted of a dentin cylinder, prepared from a human anterior tooth root, cemented into a sealable two-chamber device fabricated from a syringe needle cap. The model's lower chamber contained a buffer solution, and the dentin cylinder was placed between the upper and lower chambers. After sterilization, the authors inoculated the root canal of each dentin cylinder with E. faecalis. They used an Er,Cr:YSGG laser with radial emitting tips to irradiate the root canal of each infected dentin cylinder (varying laser power and exposure time). After laser treatment, the authors machined the root canal dentin walls and collected the resulting dentin fillings in the buffer-reservoir. They quantified the E. faecalis titer of each buffer-reservoir by using selective agar plates. RESULTS: The authors found that bacterial recovery decreased when laser irradiation duration or power increased. A greater degree of disinfection was achieved with a 120-second application of laser than with sodium hypochlorite treatment. Finally, they found that a 99.7 percent reduction in bacterial counts could be obtained using the laser. CONCLUSION: The results of this study suggest that the Er,Cr:YSGG laser with a radial emitting tip has a significant antimicrobial effect on dentinal tubules infected with E. faecalis. CLINICAL IMPLICATIONS: Er,Cr:YSGG laser treatment could be a valuable tool for root canal disinfection during endodontic treatment.
Clean / Disinfect URL  Ishizaki, N.T., Matsumoto, K., Kimura, Y., Wang, X., Kinoshita, J.-I., Okano, S.M. and Jayawardena, J.A. Thermographical and Morphological Studies of Er,Cr:YSGG Laser Irradiation on Root Canal Walls Photomedicina and Laser Surgery
Vol. 22(4), pp. 291-7 
2004 rank3
Abstract: Objective: This study was performed to investigate the temperature rises on root surfaces and morphological changes on root canal walls of extracted human teeth after irradiation by erbium, chromium: yttrium, scan- dium, gallium, garnet (Er,Cr:YSGG) laser and to evaluate the efficiency in removing smear layer and debris from the prepared root canal walls in vitro. Background Data: No report on Er,Cr:YSGG laser effects under various conditions and specific tips for endodontic treatments has been reported. Methods: Sixty extracted human teeth with single and straight root were used in this study. The teeth were prepared at 1 mm short of the apical foramen by a conventional technique using K-files. Fifty-four specimens were irradiated by Er,Cr:YSGG laser at the output powers of 2 W, 3 W, and 5 W for 7 sec with three fiber tips (200, 320, and 400 µm diameters). Temperature changes were recorded thermographically. All teeth were examined by light microscopy or scanning electron microscopy (SEM). Results: Thermographic study showed that the average temperature rises on root surfaces were less than 8°C. Observation by light microscopy revealed the ablation at the apical stop, and that by SEM indicated that laser irradiation at 5 Wusing a fiber tip with 400 µm diam- eter was efficient for removing smear layer and debris without carbonization or melting. Conclusions: The re- sults of this study suggested that the temperature rises during Er,Cr:YSGG laser irradiation at the parameters used in this study are minimal to cause the damage on periodontal and bone tissues. Moreover, it was suggested that it is efficient to remove smear layer and debris without causing any carbonization and melting.
Clean / Disinfect DOI URL  Jha, D., Guerrero, a., Ngo, T., Helfer, a. and Hasselgren, G. Inability of laser and rotary instrumentation to eliminate root canal infection. Journal of the American Dental Association (1939)
Vol. 137(1), pp. 67-70 
2006 rank2
Abstract: The authors evaluated the antibacterial effectiveness of laser instrumentation and rotary instrumentation of anterior, single-rooted teeth infected with Enterococcus faecalis.
Clean / Disinfect, Endo DOI   Juric, I.B., Plecko, V. and Anic, I. Antimicrobial Efficacy of Er,Cr:YSGG Laser-Activated Irrigation Compared with Passive Ultrasonic Irrigation and RinsEndo((R)) Against Intracanal Enterococcus faecalis Photomedicine and Laser Surgery
Vol. 32(11), pp. 600-605 
2014 rank4
Abstract: Objective: The aim of this study was to evaluate the antibacterial efficacy of active irrigation techniques: Erbium, chromium: yttrium, scandium, gallium, garnet (Er,Cr:YSGG) laser-activated irrigation (LAI), passive ultrasonic irrigation (PUI), RinsEndo((R)), and conventional syringe irrigation, against intracanal Enterococcus faecalis. Materials and methods: Root canals of 100 human extracted teeth were instrumented, sterilized in plasma, contaminated with E. faecalis, and incubated for 10 days. The samples were randomly distributed into four experimental groups (n=20 each): I: LAI by Er,Cr:YSGG (1.25 W, 20 Hz) for 4x5 sec; II. PUI for 60 sec; III. RinsEndo((R)) system for 60 sec; IV. 30 gauge syringe irrigation for 60 sec; and one positive control group (n=10). In all experimental groups, 2.5% sodium hypochlorite (NaOCl) was used as an irrigant, whereas the positive controls were rinsed with saline. The root canals were sampled by flushing with saline solution before and after the treatments, serially diluted, and cultured. The presence or absence of E. faecalis in the root canals was checked by polymerase chain reaction. Results: There were no differences among the three active irrigation techniques (p>0.05), which were more effective than the conventional syringe irrigation (p<0.001). Conclusions: LAI, PUI, and RinsEndo were equally effective in the elimination of intracanal 10-day-old E. faecalis. However, LAI generated more negative bacterial samples, which warrants further investigations.
Endo, Clean / Disinfect DOI URL  Kasić, S., Knezović, M., Beader, N., Gabrić, D., Ivanišević Malčić, A. and Baraba, A. Efficacy of Three Different Lasers on Eradication of Enterococcus faecalis and Candida albicans Biofilms in Root Canal System. Photomedicine and laser surgery
Vol. 35(7), pp. 372-377 
2017 rank4
Abstract: OBJECTIVE The objective was to compare the efficacy of three different lasers in disinfection of root canals inoculated with Enterococcus faecalis and Candida albicans biofilms. BACKGROUND Endodontic space disinfection depends on the type of root canal irrigant used and the way it is delivered and agitated because irrigants have limited ability to reach all parts of root canal system. MATERIALS AND METHODS Thirty single-rooted human teeth were selected. Root canals were instrumented and root surfaces were sealed using adhesive and the apical openings with adhesive and composite resin. Roots were fixed in Eppendorf tubes and sterilized in autoclave. The specimens were randomly divided into three experimental groups (n = 10) and inoculated with E. faecalis and C. albicans. After 7 days of incubation period, the number of E. faecalis and C. albicans colony-forming units (CFUs) was determined for each root canal. In the first experimental group, Er:YAG laser (0.3 W) with photon-induced photoacoustic streaming technique was used for root canal disinfection, in the second, Nd:YAG laser (1.5 W), and in the third, Er,Cr:YSGG (1.25 W) laser was used. After different root canal disinfection protocols, the number of E. faecalis and C. albicans CFUs was determined again for each root canal. RESULTS Er:YAG and Er,Cr:YSGG lasers eradicated significant number of E. faecalis and C. albicans CFUs (p < 0.05), while Nd:YAG laser irradiation did not result in statistically significant reduction (p > 0.05). Er,Cr:YSGG laser eradicated significantly more microorganisms in comparison with Er:YAG laser (p < 0.05). CONCLUSION Er,Cr:YSGG laser was the most efficient tool in eradication of E. faecalis and C. albicans biofilms.
Endo URL  Kolnick, J. The clinical use of the Er,Cr:YSGG laser in endodontic therapy Int Mag of Laser Dent, pp. 24-27  2011 rank4
Clean / Disinfect DOI   Licata, M.E., Albanese, A., Campisi, G., Geraci, D.M., Russo, R. and Gallina, G. Effectiveness of a new method of disinfecting the root canal, using Er, Cr:YSGG laser to kill Enterococcus faecalis in an infected tooth model Lasers in Medical Science
Vol. 30(2), pp. 707-712 
2015 rank3
Abstract: Some lasers have demonstrated to provide effective disinfection when used as adjunctive device to the conventional treatment. The aim of this in vitro study was to determine the effectiveness of the erbium, chromium:yttrium scandium gallium garnet (Er, Cr:YSGG) laser by measuring its bactericidal effect inside the root canal experimentally colonized with Enterococcus faecalis. The laser was tested at different irradiation times (30 and 60 s) and energy of impulses (75 and 25 mJ). A total of 52 single-rooted extracted human teeth were endodontically prepared with rotary instrumentation. All were sterilized and inoculated with a suspension of E. faecalis (105 bacteria/ml). The teeth were randomized into three treatment (group 1, group 2, and group 3) and one control groups. In all groups, teeth were chemically irrigated with 5.25 % sodium hypochlorite and 17 % ethylenediaminetetraacetic acid. Groups 1 and 2 were also irradiated at 30 and 60 s, respectively, with an Er, Cr:YSGG laser at 75 mJ. Teeth of group 3 were treated with laser for 60 s at 25 mJ. Samples were processed to detect the presence of E. faecalis. For all groups, a bactericidal effect was observed. The use of laser at 75 mJ with an irradiation time of 30 and 60 s eliminated a percentage of 92.3 and 100 % of E. faecalis, respectively. In the control group, a reduction of 92.3 % was observed. Lower percentage of reduction (46.1 %) was obtained in teeth treated with laser at 25 mJ for 60 s. No statistical differences were observed between the groups (P = 0.543, Fisher's exact test). The results indicated a bactericidal effect of Er, Cr:YSGG laser irradiation at the settings used in this study. The highest bactericidal effect of this laser was observed at 60 s of irradiation time, using an energy pulse of 75 mJ.
Endo DOI   López-Jiménez, L., Arnabat-Domínguez, J., Viñas, M. and Vinuesa, T. Atomic force microscopy visualization of injuries in enterococcus faecalis surface caused by ER,CR:YSGG and diode lasers Medicina Oral, Patologia Oral y Cirugia Bucal
Vol. 20(1), pp. e45-e51 
2015 rank5
Abstract: Aim: To visualize by Atomic Force Microscopy the alterations induced on Enterococcus. faecalis surface after treatment with 2 types of laser: Erbium chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser and Diode laser.Material and Methods: Bacterial suspensions from overnight cultures of E. faecalis were irradiated during 30 seconds with the laser-lights at 1 W and 2 W of power, leaving one untreated sample as control. Surface alterations on treated E. faecalis were visualized by Atomic Force Microscopy (AFM) and its surface roughness determined.Results: AFM imaging showed that at high potency of laser both cell morphology and surface roughness resulted altered, and that several cell lysis signs were easily visualized. Surface roughness clearly increase after the treatment with Er,Cr:YSGG at 2W of power, while the other treatments gave similar values of surface roughness. The effect of lasers on bacterial surfaces visualized by AFM revealed drastic alterations.Conclusions: AFM is a good tool to evaluate surface injuries after laser treatment; and could constitute a measure of antimicrobial effect that can complete data obtained by determination of microbial viability.
Endo DOI URL  Madhusudhana, K., Swapna, S., Suneelkumar, C., Lavanya, A. and Deepthi, M. Effect of endoactivator and Er,Cr:YSGG laser irradiation in removing the smear layer after root canal instrumentation: An in vitro study Journal of Dr. NTR University of Health Sciences
Vol. 5(1), pp. 24 
2016
Abstract: Aim: The objective of this study was to assess the effectiveness of smear layer removal with a newer endodontic irrigation device, i.e., endoactivator system and with hard tissue laser, i.e., erbium, chromium:yttrium, scandium, gallium garnet laser (Er,Cr:YSGG).
Materials and Methods: Forty-four mandibular premolars, single-rooted, noncarious teeth were selected. All the canals were prepared by using ProTaper Universal rotary files (Dentsply Maillefer, Ballaigues, Switzerland) and 3% NaOCl. Teeth were then divided into two control groups and two experimental groups. Group A: Negative control group (N = 11)- without any final irrigation, Group B: Positive control group (N = 11)- final rinse with 1 mL smear clear for 1 min using no. 30 gauge needle, Group C: Endoactivator group (N = 11)-1 mL smear clear + endoactivator, Group D: Er,Cr:YSGG laser group (N = 11). Teeth were sectioned and observed for smear layer removal at apical, middle, and coronal thirds under scanning electron microscope (SEM).
Results: Results were interpreted analytically by Kruskal-Wallis test and Wilcoxon signed-ranks test.
Conclusion: The two experimental groups were significantly more efficient in smear layer removal than the control groups. There was no significant difference between the endoactivator and laser groups. All groups showed more efficient smear layer and debris removal coronally than in the middle and apical regions.
Endo, Apicoectomy DOI URL  Martins, M.R., Carvalho, M.F., Pina-Vaz, I., Capelas, J.A., Martins, M.A. and Gutknecht, N. Outcome of Er,Cr:YSGG Laser-Assisted Treatment of Teeth with Apical Periodontitis: A Blind Randomized Clinical Trial Photomedicine and Laser Surgery
Vol. 32(1), pp. 3-9 
2014 rank5
Abstract: Objective: As clinical studies conducted to explore the safety and efficacy of new procedures are considered an important focus in endodontic research, the aim of this controlled clinical study was to compare a laser-assisted endodontic treatment using an erbium, chromium:yttrium–scandium–gallium–garnet (Er,Cr:YSGG) laser and radial firing tips (RFT) versus the conventional use of 3% sodium hypochlorite and interim calcium hydroxide paste, in teeth with chronic apical periodontitis. Methods: Forty-three single-rooted and premolar teeth were randomly assigned. In group 1, teeth were prepared and irrigated with 3% sodium hypochlorite and calcium hydroxide inter-appointment dressing was applied; in group 2 teeth were prepared with saline solution and irradiated with Er,Cr:YSGG laser using RFT2 (140 μs, 37.5 mJ, 20 Hz) and RFT3 (140 μs, 62.5 mJ, 20 Hz) at the first and second appointments, respectively, four times each, moving at 2 mm/sec−1 from apical to coronal. The primary outcome measure was change in apical bone density at 12 months, using the periapical index (PAI) for blind radiographic assessment. Results: Thirty teeth were examined and subjected to statistical analysis, 12 in the control group and 18 in the test group. There were two treatment failures in the control group that were not included for analysis; both groups exhibited statistically significant decreases in PAI scores. Conclusions: The present findings suggest that for single-rooted and premolar teeth, this laser-assisted protocol can achieve predictable endodontic outcomes, comparable to conventional strategies in 1 year of follow-up.
Endo DOI URL  Martins, M.R., Carvalho, M.F., Vaz, I.P., Capelas, J.a., Martins, M.a. and Gutknecht, N. Efficacy of ErCrYSGG laser with endodontical radial firing tips on the outcome of endodontic treatment: blind randomized controlled clinical trial with six-month evaluation Lasers in medical science  2012 rank5
Abstract: Clinical reports stating the efficacy of novel root canal disinfection protocols are an important focus in endodontic research. This blind randomized clinical trial assessed the clinical efficacy of the erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser radial firing tips (RFT) versus the concomitant use of 3 % sodium hypochlorite and interim calcium hydroxide paste in necrotic teeth with chronic apical periodontitis. We hypothesized to find similar or improved bone healing in the laser-assisted endodontic treatment. Thirty-six anterior and premolar teeth were randomly assigned. In group 1, teeth were prepared with 3 % sodium hypochlorite for irrigation and calcium hydroxide as inter-appointment dressing; in group 2, teeth were prepared with saline solution and irradiated with Er,Cr:YSGG laser using RFT2 (140 μs, 37.5 mJ, 20 Hz) and RFT3 (140 μs, 62.5 mJ, 20 Hz) in the first and second appointment, respectively, four times each, moving at 2 mm s(-1) from apical to coronal. The primary outcome measure was changed in apical bone density at 6 months, using the periapical index (PAI) for blind radiographic evaluation. Twenty-nine patients were examined and subjected to statistical analysis, 12 in group 1 and 17 in group 2. There was one treatment failure in group 1. Both groups gave similar outcomes exhibiting statistically significant decreases in PAI scores.
Endo, Clean / Disinfect DOI   Martins, M.R., Franzen, R., Depraet, F. and Gutknecht, N. Rationale for using a double-wavelength (940 nm + 2780 nm) laser in endodontics: literature overview and proof-of-concept Lasers in Dental Science
Vol. 2(1), pp. 29-41 
2018
Abstract: Aim The goal of endodontic research is to report interventions, techniques or protocols that are most likely to deliver the outcomes that are of most interest to both clinicians and patients. The development of a double-wavelength laser delivered concomitantly and through the same radial firing tip (RFT) may provide a unique combination of beneficial properties that may clinically surpass all previously reported laser-assisted protocols. The aim is to present a rational literature overview that could support the adoption of simultaneous use 2780 and 940 nm wavelengths for smear layer removal and disinfection respectively. Methods In order to provide relevant clinical data, two distinct clinical cases of relatively high endodontic complexity are reported with 1-year follow-up. Results The results of both clinical cases show the immediate remission of symptoms, absence of clinical complications and complete radiographic healing. Conlusions Together with the available amount of literature that could support the effectiveness of these two wavelengths to remove SL and to achieve deep dentin disinfection, it is possible to expect that this innovative combination of lasers delivered by RFT may be of high clinical relevance in the near future.
Clean / Disinfect DOI   Minas, N.H., Gutknecht, N. and Lampert, F. In vitro investigation of intra-canal dentine-laser beam interaction aspects: II. Evaluation of ablation zone extent and morphology Lasers in Medical Science
Vol. 25(6), pp. 867-872 
2010 rank4
Abstract: Laser endodontic tips appear to provide a promising alternative to available treatment modalities in the field of endodontology. With the shortcomings in published results regarding the intra-canal behavioural aspects of those tips, it was the aim of this study to investigate the extent of the intra-canal ablation zone and the pattern associated with those tips. Ninety intact extracted bovine teeth were used to prepare mid-root testing cylinders. The samples were divided into three groups (A, B, C), corresponding to the tip diameters. Each group was further subdivided to be irradiated at three different power settings (1500 mW, 1750 mW, 2000 mW) with an erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser with a 65% water to 35% air ratio. Collected data were subjected to analysis of variance (ANOVA) and the Tukey test. At a chosen significance level of alpha = 1%, no statistical difference was found among the groups (P > 0.01). The results suggest that shortening of the estimated working length is mandatory for the use of those tips within the canal, and that, provided that certain measurements are used for intra-canal laser ablation, this is a secure mode of treatment. Further investigation and system improvement will be required for more satisfactory results.
Clean / Disinfect DOI URL  Minas, N.H., Meister, J., Gutknecht, N. and Lampert, F. In vitro investigation of intra-canal dentine-laser beam interaction aspects: I. Evaluation of ablation capability (ablation Lasers in Medical Science
Vol. 25, pp. 835-840 
2010 rank4
Abstract: The aim of this study was to determine the amount of intra-canal dentine removed with an erbium, chromium: yttrium–scandium–gallium–garnet (Er,Cr:YSGG) laser using different endodontic tips and different power settings. Ninety intact extracted bovine teeth were selected as samples. After sectioning the roots and preparing the testing cylinders, we divided the samples into three main groups (A, B, C), with further subdivision of each group to be irradiated with three different powers (1500mW, 1750mWand 2000mW). An Er, Cr:YSGG laser system (2.78 μm, 140 μs, 20 Hz and 65% water to 35%air ratio) was used for irradiation, and the loss of intra-canal dentine mass was calculated by the difference between the initial and final sample masses. Data were analysed with Kolmogorov–Smirnov, analysis of variance (ANOVA) and Tukey tests. At a significance level of α=1%, the results showed statistically significant differences (P< 0.0001) between different tip groups, regarding both the ablation rate and the ablation efficiency criteria. With regard to the three irradiation power settings, statistically significant difference were recorded only between groups C and A, for the ablation rate criteria. The intra-canal ablation ability of the Er,Cr:YSGG laser improved with increasing power and/ or tip diameter. The latter exhibited a stronger influence on ablation rate and efficiency. Laser intra-canal ablation is an important addition to the field of endodontics; nevertheless, further investigations and system improvements are required.
Clean / Disinfect DOI   Mohammadi, N., Savadi Oskoee, S., Abed Kahnamoui, M., Bahari, M., Kimyai, S. and Rikhtegaran, S. Effect of Er,Cr: YSGG pretreatment on bond strength of fiber posts to root canal dentin using a self-adhesive resin cement Lasers in Medical Science
Vol. 28(1), pp. 65-69 
2013 rank4
Abstract: The weak link in the adhesive luting of fiber posts to root canal dentin is at the cement-dentin interface. The aim of the present study was to evaluate the effect of Er,Cr:YSGG laser irradiation on push-out bond strength of fiber posts cemented to root canal dentin using a self-adhesive cement. A total of 30 sound human maxillary central incisors were equally divided into two groups after root canal treatment, decoronation and preparation of the post space. Teeth of group 1 were treated with the Er,Cr:YSGG laser, and teeth of group 2 (control) received no laser treatment. After cementation of fiber posts with Maxcem self-adhesive cement, 3-mm cervical, middle and apical sections were prepared from the roots. Then a push-out test was performed using a universal testing machine at a strain rate of 0.5 mm/min. Data were analyzed using two-way ANOVA and the Bonferroni test. Statistical significance was defined as P < 0.05. There was a significant difference in the mean bond strength values between groups 1 and 2 (P = 0.001), but there were no significant differences between the various root parts (P = 0.14). In addition, the cumulative effects of dentin treatment type and various root parts were not statistically significant (P = 0.41). The mean bond strength in the laser group was significantly higher than in the control group (P = 0.001, post hoc Bonferroni test).The failure mode was evaluated under a stereomicroscope at × 20 magnification.
Endo DOI URL  Onay, E.O., Alikaya, C. and Seker, E. Evaluation of antifungal efficacy of erbium, chromium: yttrium-scandium-gallium-garnet laser against Candida albicans. Photomedicine and laser surgery
Vol. 28 Suppl 1, pp. S73-8 
2010 rank3
Abstract: The purpose of this in vitro study was to investigate the ability of Er,Cr:YSGG laser irradiation at different energy settings to eliminate Candida albicans, either with or without 5.25% sodium hypochlorite (NaOCl) treatment.
Clean / Disinfect DOI URL  Onay, E.O., Gogos, C., Ungor, M., Economides, N., Lyssaris, V., Ogus, E. and Lambrianidis, T. Effect of Er,Cr:YSGG laser irradiation on apical sealing ability of calcium silicatecontaining endodontic materials in root-end cavities. Dental materials journal
Vol. 33(4), pp. 570-5 
2014 rank4
Abstract: The aim of this research was to evaluate the apical sealing abilities of 60 root-end cavities filled with mineral trioxide aggregate (MTA) and iRoot BP cements after treated with either 17% EDTA solution or Er,Cr:YSGG laser irradiation. After the filling procedure, apical leakage quantity was measured at 4 weeks using a fluid filtration method. One root from each group was processed for scanning electron microscopy and energy dispersive X-ray spectroscopy analyses. Both EDTA/MTA and laser irradiation/MTA combinations showed significantly lower microleakage than EDTA/iRoot BP and laser irradiation/iRoot BP combinations (p<0.05). Between groups of the same filling material, there were no significant differences among specimens treated with EDTA or laser (p>0.05). Both MTA and iRoot-BP demonstrated tag-like structures within the dentinal tubules when used in conjunction with EDTA.
Clean / Disinfect DOI   Onay, E.O., Orucoglu, H., Kiremitci, A., Korkmaz, Y. and Berk, G. Effect of Er,Cr:YSGG laser irradiation on the apical sealing ability of AH Plus/gutta-percha and Hybrid Root Seal/Resilon Combinations Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology and Endodontology
Vol. 110(5), pp. 657-664 
2010 rank4
Abstract: Objective: The objective of this study was to evaluate the sealing ability of 2 different resin-based endodontic filling systems after smear layer removal with 2 different techniques. Study design: Extracted human single-rooted teeth (n = 74) were instrumented using HERO Shaper rotary instruments and irrigated with 1 mL of 2.5% NaOCl between each instrument. Additionally, the canals received either an extra 3-minute rinse with 2 mL of 17% EDTA or a 40-second Er,Cr:YSGG laser treatment. The root canals were filled with either Hybrid Root Seal/Resilon combination or AH Plus/gutta-percha combination using lateral condensation technique (n = 11). Apical leakage quantity was measured with the computerized fluid filtration meter at 1 and 4 weeks. One root from each group, which was not submitted to the fluid filtration test, was selected for scanning electron microscopy (SEM) analysis. Statistical analysis was performed using 3-way ANOVA and the post hoc Tukey HSD test (?? = 0.05). Results: A significant decrease was observed in the microleakage values of all the experimental groups tested with time (P < .0001). EDTA + AH Plus/gutta-percha combination exhibited the least microleakage, whereas laser irradiation + Hybrid Root Seal/Resilon combination showed the greatest microleakage at each of the 2 time periods. Each experimental combination exhibited architecture in SEM that seemed to correlate with its sealing performance. Conclusion: Er,Cr:YSGG laser treatment does not enhance the sealing ability of the sealers compared with EDTA application. The root canal adaptation and sealing ability of the Hybrid Root Seal/Resilon combination is not superior to that of the AH Plus/gutta-percha combination.
Clean / Disinfect DOI   Özer, S.Y. and Basaran, E. Evaluation of microleakage of root canal fillings irradiated with different output powers of erbium, chromium: Yttrium-scandium-gallium-garnet laser Australian Endodontic Journal
Vol. 39(1), pp. 8-14 
2013 rank3
Abstract: This study evaluated the root canal seal achieved by irradiation with an erbium, chromium:yttrium-scandium-gallium-garnet laser, and the optimal output power to remove debris and the smear layer were determined. One hundred mandibular premolar teeth were prepared and divided into four groups. Group 1 was not lased but was irrigated with 5 mL of 5.25% NaOCl and 5 mL of 17% ethylenediaminetetraacetic acid. Group 2 was irradiated at a panel setting of 1 W, group 3 at 2 W and group 4 at 2.5 W, with a 50% water level and 48% air-cooling level. Root canals were obturated by cold lateral compaction, and apical microleakage was measured using a fluid filtration model. The remaining debris and smear layer were evaluated via scanning electron microscopy. Statistically significant differences were detected between groups. Irradiation at 1 and 2 W using an erbium, chromium:yttrium-scandium-gallium-garnet laser produced a seal superior to that of the other treatments.
Clean / Disinfect DOI   Peeters, H.H. and De Moor, R.J. Measurement of pressure changes during laser-activated irrigant by an erbium, chromium: yttrium, scandium, gallium, garnet laser Lasers in Medical Science
Vol. 30(5), pp. 1449-1455 
2015 rank5
Abstract: The use of Er,Cr:YSGG laser to activate irrigants results in the creation of vapour bubbles and shockwaves. The present study evaluated the magnitude of pressure changes in the root canal during laser-activated irrigation. The root canal of a single extracted maxillary canine was enlarged to a size 40/0.06 file. A pressure sensor was inserted apically into the root canal. The tooth was processed as follows. In the EDTA condition, the tooth was irrigated with 17 % EDTA; in the NaOCl condition, the tooth was irrigated with 3 % NaOCl. In all conditions, the irrigants were activated at 0.75 and 1.75 W for 60 s using RFT2 and MZ2 tips; to analyse the effect of tip placement, the tip was activated at the orifice and after inserting the tip 5 mm deeper than the orifice. Data showed no significant difference between irrigation regimens (p > 0.05). There were no significant differences of the pressure between RFT2 and MZ2 tips (p > 0.05). The placement of tips closer to the apex resulted in significantly higher pressure than at the orifice (p < 0.001). The use of 1.75 W power resulted in a significantly higher increase of pressure compared to 0.75 W (p < 0.001), regardless either the type of solutions or tips used. The magnitude of the pressure changes in the root canal at 0.75 W was significantly lower than 1.75 W regardless of either type of tips or solutions used. The closer the insertion of the tip to the apex, the higher the pressure.
Clean / Disinfect DOI   Peeters, H.H., De Moor, R.J.G. and Suharto, D. Visualization of removal of trapped air from the apical region in simulated root canals by laser-activated irrigation using an Er,Cr:YSGG laser Lasers in Medical Science
Vol. 30(6), pp. 1683-1688 
2015 rank5
Abstract: The aim of this visualization study was to obtain a better understanding of the mechanism by which trapped air is removed from the apical region of simulated root canals by activation of an irrigant using an erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser during endodontic procedures. A high-speed imaging system with high temporal and spatial resolution was used to visualize laser-induced shock waves in a resin block model with a curved root canal (inner diameter at the apex 0.08 mm, taper 4 %, crown height 10 mm, overall length 40 mm) and a glass cylinder model with a straight root canal (inner diameter 1 mm, crown height 10 mm, overall length 40 mm). The study utilized MZ3 and RFT3 tips in each model, without water or air spray, and with an average power of 1 W at 35 Hz. Laser-activated irrigation overcame the airlock effect by releasing air trapped in the air column. The mechanism underlying the removal of trapped air from the apical region using an Er,Cr:YSGG laser in a dry root canal is via the disruption of the surface tension at the solution-air interface. This disruption, caused by bubble implosion (cavitation), displaces air in the form of bubbles from the apical region toward the solution, which allows the solution to travel apically.
Endo DOI URL  Peeters, H.H. and Gutknecht, N. Efficacy of laser-driven irrigation versus ultrasonic in removing an airlock from the apical third of a narrow root canal Australian Endodontic Journal
Vol. 40(2), pp. 47-53 
2014 rank5
Abstract: The purpose of the study was to test the hypothesis that air entrapment occurs in the apical third of a root canal during irrigation. A second objective was to test the null hypothesis that there is no difference between laser-driven irrigation (an erbium, chromium:yttrium-scandium-gallium-garnet laser) and passive ultrasonic irrigation in removing an airlock from the apical third. One hundred twenty extracted human teeth with single narrow root canals were randomised into two experimental groups (n = 40) and two control groups (n = 20). The specimens were shaped using hand instruments up to a size 30/0.02 file. The teeth were irrigated with a mixture of saline, radiopaque contrast and ink in solution. In the passive ultrasonic irrigation group, the irrigant was activated with an ultrasonic device for 60 s. In the laser group, the irrigant was activated with a laser for 60 s. It was concluded that if the insertion of irrigation needle is shorter than the working length, air entrapment may develop in the apical third, but the use of laser-driven irrigation is completely effective in removing it.
Clean / Disinfect DOI URL  Peeters, H.H. and Suardita, K. Efficacy of smear layer removal at the root tip by using ethylenediaminetetraacetic acid and erbium, chromium: Yttrium, scandium, gallium garnet laser Journal of Endodontics
Vol. 37(11), pp. 1585-1589 
2011 rank3
Abstract: Introduction: The purpose of this study was to compare the efficacy of laser-driven irrigation in removing the smear layer and debriding the apical region of the root canal (the root tip) with that of ultrasonic irrigation. Methods: Forty extracted human teeth with straight single roots were randomized into 4 groups (n = 10). The specimens were shaped by using hand instruments up to a size 30/.02 file (Control, Laser 1, and Laser 2 groups) or a size 20/.02 file (Laser 3 group). During instrumentation, each canal was irrigated with 3% NaOCl and 17% ethylenediaminetetraacetic acid alternately between the use of successive files. The 4 groups of 10 teeth were processed as follows. In the Control group, teeth were irrigated with 17% ethylenediaminetetraacetic acid, and the irrigant was activated with an ultrasonic device for 60 seconds. In the Laser 1 and Laser 3 groups, the irrigant was activated with the laser for 60 seconds. In the Laser 2 group, the irrigant was activated with the laser for 30 seconds. Results: There were significant differences between the smear layer and debris scores for the Laser 1 group and those for the Control (P <.001), Laser 2 (P =.002), and Laser 3 groups (P =.012 and P =.013, respectively). Completely clean root canals were found in the Laser 1 group. Conclusions: Use of a laser with a plain fiber tip, which produces cavitation in the irrigant, has potential as an improved alternative method for removing of the smear layer from the apical region of a straight root canal. Copyright textcopyright 2011 American Association of Endodontists.
Endo URL  Preethee, T., Kandaswamy, D., Arathi, G. and Hannah, R. Bactericidal effect of the 908 nm diode laser on Enterococcus faecalis in infected root canals Journal of Conservative Dentistry
Vol. 15(1), pp. 46-50 
2012 rank2
Abstract: Aim: The aim of this study is to evaluate the bactericidal effect of 908 nm diode laser in conjunction with various irrigation regimes in disinfection of apical third of root dentin. Materials and Methods: Sixty prepared teeth with single canals were contaminated with Enterococcus faecalis. The specimens were divided into 6 groups (n = 10): Group 1 and 3 and 5 were subjected to chemo-mechanical preparation using 5.25% sodium hypochlorite (NaOCl), 17% Ethylenediaminetetraacetic acid (EDTA); 1.3% NaOCl, MTAD (mixture of doxycycline, citric acid and a detergent (Tween 80); and, 8.5% saline, respectively followed by 908 nm diode laser irradiation; Group 2 and 4, followed the same procedure as Group1 and 3, however without laser irradiation; and, Group 6, rinsed with saline solution (control). Dentin shavings from apical third were analyzed for the presence of E. faecalis using culture method and Polymerase Chain reaction (PCR). Results: One-way Analysis of variance showed statistically significant differences between the laser irradiated groups, non irradiated groups and the control group. Conclusion: 908 nm diode used in conjunction with conventional chemomechanical techniques demonstrated a significant elimination of E. faecalis in the apical third of root dentin.
Endo DOI URL  Quinto, J., Amaral, M.M., Francci, C.E., Ana, P.A., Moritz, A. and Zezell, D.M. Evaluation of Intra Root Canal Er,Cr:YSGG Laser Irradiation on Prosthetic Post Adherence Journal of Prosthodontics, pp. 1-5  2017 rank4
Abstract: Purpose
In clinical prosthetics procedures, including endodontics and post fixation, the presence of a smear layer can reduce the post bond strength. An Er,Cr:YSGG laser, which emits at 2780 nm, can promote a smear‐layer‐free surface due to the ablation process. Considering these aspects, the purpose of this work was to evaluate the influence of Er,Cr:YSGG laser irradiation using either a radial or an axial fiber tip on the bond strength of three resin cements to the fiber‐reinforced composite posts.

Materials and Methods
Ninety recently extracted single rooted human teeth had their root canal instrumented and were randomly distributed into nine experimental groups, in which three resin cements (total‐etching Variolink II, self‐etching Panavia F, and self‐adhesive RelyX Unicem Aplicap) and three root canal treatments (no treatment, laser irradiation using the radial fiber tip, laser irradiation using the axial fiber tip) were used. Specimens were then sectioned into three sections (cervical, middle, and apical thirds) with two slices on each section. A push‐out test was performed on each slice, and the values were recorded as MPa. The push‐out data were analyzed by a Ryan‐Joiner normality test followed by a two‐way ANOVA test and Tukey pairwise comparison. The statistical analysis was performed on each third section separately, with a 5% significance level.

Results
Laser irradiation with axial fiber tip significantly increased the post bond strength of RelyX Unicem Aplicap on middle third of specimens (p < 0.001) when compared to other root canal treatments (unlased or irradiated with radial tip). Considering the Panavia resin cement, laser irradiation with either axial or radial tips promoted a significant increase on the post bond strength of middle third when compared to unlased specimens (p < 0.001); however, laser irradiation did not influence the post bond strength of Variolink resin cement.

Conclusions
The use of the Er,Cr:YSGG laser for clinical prosthetics procedures enhances the post bond strength of Panavia and RelyX Unicem Aplicap resin cements, mainly at middle third of roots, and does not interfere with the bond strength of Variolink resin cement. For the RelyX Unicem Aplicap system, the use of axial tip is most advantageous and can be recommended for future clinical application.
Apicoectomy, Endo, Restorative DOI   Rahimi, S., Yavari, H.R., Shahi, S., Zand, V., Shakoui, S., Reyhani, M.F. and Pirzadeh, A. Comparison of the effect of Er, Cr-YSGG laser and ultrasonic retrograde root-end cavity preparation on the integrity of root apices. Journal of oral science
Vol. 52(1), pp. 77-81 
2010 rank4
Abstract: The aim of this study was to compare the effect of Waterlase laser and ultrasonic root end cavity preparation on the integrity of root end in extracted human teeth. The canals of 60 extracted maxillary central incisors were cleaned, shaped, obturated and 3 mm of the root end was resected and examined for the presence of any cracks. Class I root-end cavities were then prepared using an ultrasonic unit or Waterlase laser. In the ultrasonic group, KIS 2D tip and medium intensity and in the laser group, 600 mum laser tips and an output power setting of 4 W with 55% water and 65% air were used to prepare the cavity which was studied for the presence of any cracks or chippings. One crack was found in the ultrasonic group, while no cracks were observed in the laser group. There was no significant difference between the two groups (P > 0.05). As for the chipping effect, seven cases (23%) had chipping after cavity preparation in the ultrasonic group but no chipping was found in the specimens of the laser group and the difference was statistically significant (P < 0.05). According to the results of this in vitro study, laser preserves the integrity of root-end cavities better than ultrasonic devices from the standpoint of producing chipping.
Clean / Disinfect DOI   Schoop, U., Barylyak, A., Goharkhay, K., Beer, F., Wernisch, J., Georgopoulos, A., Sperr, W. and Moritz, A. The impact of an erbium, chromium:yttrium-scandium-gallium-garnet laser with radial-firing tips on endodontic treatment Lasers in Medical Science
Vol. 24(1), pp. 59-65 
2009 rank4
Abstract: Radial-firing tips should allow a more homogeneous laser irradiation of root canal walls. The aim of the study was to assess the effects of erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser irradiation in conjunction with those newly designed tips. The investigation comprised bacteriology, morphological evaluations and temperature measurements. Root canals were inoculated with two test strains and laser irradiated with power settings of 0.6 W and 0.9 W and a repetition rate of 20 Hz. Subsequently, the samples were subjected to microbiological evaluation. The morphological changes of the canal walls were assessed by scanning electron microscopy. To reveal possible thermal side effects, we carried out temperature measurements. The bacteriological evaluation revealed a decisive disinfectant effect. Scanning electron microscopy showed the homogeneous removal of smear layer from the root canal walls. The temperature rise at the root surface during the irradiation was moderate, yielding 1.3 degrees C for the 0.6 W setting and 1.6 degrees C for the 0.9 W setting. The investigations indicated that the Er,Cr:YSGG laser, in conjunction with radial-firing tips, is a suitable tool for the elimination of bacteria in root canals and for the removal of smear layer.
Clean / Disinfect DOI URL  Schoop, U., Goharkhay, K., Klimscha, J., Zagler, M., Wernisch, J., Georgopoulos, A., Sperr, W. and Moritz, A. The use of the erbium, chromium:yttrium- scandium-gallium-garnet laser in endodontic treatment JADA
Vol. 138(7), pp. 949-55 
2007
Abstract: Background. The use of the erbium, chromium:yttrium-scandium- gallium-garnet (Er,Cr:YSGG) laser has become accepted in the field of cavity preparation. The development of miniaturized and flexible fiber tips has allowed this device to be used in endodontics. The authors con- ducted an in vitro study to assess the effects of Er,Cr:YSGG laser irradia- tion on root canals. Methods. The authors inoculated root canals with two bacteria, laser irradiated them at two power settings and subjected them to a quantita- tive microbiological evaluation. They used scanning electron microscopy (SEM) to assess morphological changes in endodontically processed and laser-irradiated root canal walls. They measured temperature increases on the root surface to determine possible thermal side effects. Results. The bacteriological evaluation revealed a disinfecting effect in the root dentin samples that was dependent on the output power but not specific for the bacterial species investigated. SEM showed the removal of the smear layer from the root canal walls and the exposure of dentinal tubules. The temperature rise during irradiation was moderate when standardized power settings were used. Conclusions. The Er,Cr:YSGG laser can be used to eliminate bacteria in root canals. It also effectively removes smear layer and debris from the canal wall. Clinical
Clean / Disinfect DOI   Schoop, U., Kluger, W., Moritz, A., Nedjelik, N., Georgopoulos, A. and Sperr, W. Bactericidal effect of different laser systems in the deep layers of dentin Lasers in Surgery and Medicine
Vol. 35, pp. 111-116 
2004 rank4
Abstract: Background and Objectives
In recent years, various laser systems have gained importance in the field of laser-assisted endodontics, namely the Nd:YAG, the diode, the Er:YAG, and the Er,Cr:YSGG laser. Individual studies have been carried out so far, focusing on the respective wavelength, its specific bactericidal capabilities, and potential usefulness is root-canal disinfection. The present in vitro investigation however, was performed to compare the microbicidal effect of these laser systems under standardized conditions and to draw a conclusion upon their relative effectiveness in the deep layers of dentin.

Study Design/Materials and Methods
In total, 360 slices of root dentin with a thickness of 1 mm were obtained by longitudinal cuts of freshly extracted human premolars. The samples were steam sterilized and subsequently inoculated with a suspension of either Escherichia coli or Enterococcus faecalis. After the incubation, the samples were randomly assigned to the four different laser systems tested. Each laser group consisted of two different operational settings and a control. The dentinal samples underwent “indirect” laser irradiation through the dentin from the bacteria-free side and were then subjected to a classical quantitative microbiologic evaluation. To assess the temperature increase during the irradiation procedure, additional measurements were carried out using a thermocouple.

Results
Microbiology indicated that all laser systems were capable of significant reductions in both test strains. At an effective output power of 1 W, E. coli was reduced by at least three log steps in most of the samples by the tested wavelengths, with the best results for the Er:YAG laser showing complete eradication of E. coli in 75% of the samples. E. faecalis, a stubborn invader of the root canal, showed minor changes in bacterial count at 1 W. Using the higher setting of 1.5 W, significant reductions of E. coli were again observed with all laser systems, where only the diode and the Er:YAG laser were capable of complete eradication of E. faecalis to a significant extent. There was no significant relation between the temperature increase and the bactericidal effect.

Conclusions
The present study demonstrates that all the wavelengths investigated are suitable for the disinfection of even the deeper layers of dentin and may prove to constitute valuable tools in state-of-the-art endodontics.
Clean / Disinfect DOI   Silva, A.C.B., Guglielmi, C., Meneguzzo, D.T., Correa Aranha, A.C., Bombana, A.C. and Eduardo, C.d.P. Analysis of Permeability and Morphology of Root Canal Dentin After Er,Cr:YSGG Laser Irradiation Photomedicine and Laser Surgery
Vol. 28(1), pp. 103-108 
2010 rank4
Abstract: Objective: The aim of this study was to evaluate the morphology and permeability of root canal walls irradiated with Er,Cr:YSGG laser after conventional endodontic treatment. Background: Laser irradiation can be used for dentinal tubule exposure, smear layer removal, and disinfection. Another potential, interesting application is as an adjunct to endodontic treatment, especially in the intracanal medication phase. Methods: Fifty-two single- rooted teeth had their crowns sectioned at the cementoenamel junction and were randomly divided into four groups (n¼13): G1: conventional preparation (CP)þirrigation with EDTA-Tþrhodamine B dye solution as- sociated with NDP (dexamethasone phosphate, paramonochlorophenol, polyethylenoglycol) (Rhod-NDP); G2: CPþEDTA-TþEr,Cr:YSGG laser irradiation 0.75WþRhod-NDP; G3: CPþEDTA-TþEr,Cr:YSGG 1.5WþRhod-NDP; G4: CPþEDTA-TþEr,Cr:YSGG 2.5WþRhod-NDP. For the permeability analysis (n¼9), teeth were transversely cut and two slices of each third were selected. The images were analyzed by ImageLab software (Softium Informa ´tica Ltda., Sa ˜o Paulo, SP, Brazil). Additional samples (n¼4) were examined by scanning electron microscopy. Results: Data were analyzed statistically using the Kruskal-Wallis and Student- Newman-Keuls tests for the following areas: apical third (H¼23.4651): G1 (14.25)a, G2 (17.66)ab, G3 (26.50)b, G4 (39.58)c; medium (H¼23.1611): G1 (14.16)a, G2 (16.66)ab, G3 (28.83)b, G4 (38.33)b; and cervical (H¼32.4810): G1 (9.66)a, G2 (20. 00)ab, G3 (27.00)b, G4 (41.33)c, (p<0.01). Despite the irregular aspect of laser irradiation along the canal walls, the parameters of 1.5W and 2.5W allowed morphologic modifications that increased dentinal permeability. Conclusions: Irradiation with Er,Cr:YSGG laser could be effective in endodontic treatment for increasing dentinal permeability.
Endo DOI URL  Soares, F., Varella, C.H., Pileggi, R., Adewumi, A. and Guelmann, M. Impact of Er,Cr:YSGG laser therapy on the cleanliness of the root canal walls of primary teeth. Journal of endodontics
Vol. 34(4), pp. 474-7 
2008 rank5
Abstract: Root canal therapy might be required for primary teeth displaying signs of pulpal inflammation or necrosis. Cleaning and shaping followed by obturation of the canal space with a resorbable paste have been widely performed with remarkable clinical success. However, lengthy endodontic procedures might be contraindicated when treating certain pediatric patients. The aim of this study was to compare the cleanliness of the root canal walls of primary teeth and the time required for the completion of the cleaning and shaping procedures performed by the Er,Cr:YSGG laser, manual or rotary instrumentation techniques. Thirty-five extracted, single-rooted, primary teeth were divided into 4 groups: I, canals were instrumented with Profile .04 rotary instruments to a master apical file size #35; II, the laser was used (parameters: 1.50 W, 20 pps, 30% water and 50% air) with a Z3 laser tip (0.32-mm diameter); III, canals were instrumented with stainless steel K-files; and IV, no instrumentation was performed (control). The teeth were split in 2 halves and prepared for scanning electron microscopy analysis. Images from the coronal, middle, and apical thirds of the roots were analyzed independently by 2 calibrated, blinded evaluators. Statistical analysis revealed significant differences among the groups (Kruskal-Wallis, P = .0001). The techniques were not capable of providing completely clean canals. Treatment with Er,Cr:YSGG laser provided similar cleanliness when compared with rotary instrumentation technique and was superior to manual instrumentation. The laser technique required less time for completion of the cleaning and shaping procedures when compared with both rotary or hand instrumentation.
Endo, Apicoectomy DOI URL  Sullivan, J., Pileggi, R. and Varella, C. Evaluation of Root-End Resections Performed by Er,Cr:YSGG Laser with and without Placement of a Root-End Filling Material. International journal of dentistry
Vol. 2009, pp. 798786 
2009 rank3
Abstract: Microleakage following root-end resections has a direct influence on the outcome of surgical endodontic procedures. This study compared the microleakage after root-end resections performed by the Er,Cr:YSGG laser or carbide burs with or without the placement of MTA, and evaluated the presence of microcracks and gaps at the interface of GP/MTA and the canal walls. Ninety single-rooted teeth were instrumented, obturated with GP and AH-Plus sealer, and divided into 3 experimental groups: (I) root-end resections were performed with the laser and G6 tips (parameters: 4.5 w, 30 pps, 20% water and 50% air); (II) Lindeman burs were used, without the placement of MTA; (III) the burs were used followed by root-end fillings with MTA, and one control (IV) of five unobturated roots resected with the burs. The samples were prepared for microleakage (n = 20) and SEM (n = 10) analysis. They were immersed in 1% methylene blue, decalcified, cleared, and evaluated for dye penetration (mm(2)) with the ImageJ software. Epoxy-resin replicas of the root-ends were analyzed by SEM for gaps (mum(2)) and microcracks. Microleakage results were 0.518 +/- 1.059, 0.172 +/- 0.223, and 0.158 +/- 0.253, for the laser (I), no root-end filling (II), and MTA (III) samples, respectively, (ANOVA P = .02). The laser (7831.7 +/- 2329.2) and no root-end filling (7137.3 +/- 1400.7) samples presented gaps. Whereas, none was found in the MTA (ANOVA P = .002). Microcracks were not observed. The MTA group demonstrated statistically less leakage and better adaptation to the canal walls when compared to the other groups. There was no correlation between the size of the gaps and the degree of microleakage.
Endo URL  Türkün, M., Türkün, L.S., Celik, E.U. and Ates, M. Bactericidal Effect of Er,Cr:YSGG Laser on Streptococcus mutans Dental Materials Journal
Vol. 25(1), pp. 81-6 
2006 rank3
Abstract: The aim of this study was to compare the antibacterial activities of Er,Cr:YSGG laser with two different power outputs against a chlorhexidine gluconate-based cavity disinfectant. A cavity tooth model test was used to determine the antibacte- rial activity. Four cylindrical cavities were prepared on the dentin surface of 10 bovine incisors and left in contact with Streptococcus mutans for 72 hours to allow bacterial invasion. Following which, Er,Cr:YSGG laser with 0.75 W and 1 W power outputs and a chlorhexidine gluconate-based cavity disinfectant were applied separately on one of the three infected cavities, whereas the fourth was left untreated for control. Standardized amounts of dentin chips were obtained from the cavity walls, and the number of bacteria recovered was counted. Statistical analysis was carried out using one-way ANOVA and Dunnett's C test(p=0.05). No significant differences were observed among the data obtained from the chlorhexidine gluconate-based cavity disinfectant and the two Er,Cr:YSGG laser groups(p>0.05). However, when compared to the control group, both Er,Cr:YSGG laser groups and the chlorhexidine gluconate-based cavity disinfectant resulted in significantly less bacterial recovery(p<0.05). In conclusion, the antibacterial activity on S. mutans demonstrated by Er,Cr:YSGG laser with both energy outputs was similar to that of the tested chlorhexidine gluconate-based cavity disinfectant.
Clean / Disinfect DOI   Varella, C.H. and Pileggi, R. Obturation of Root Canal System Treated by Cr, Er: YSGG Laser Irradiation Journal of Endodontics
Vol. 33(9), pp. 1091-1093 
2007 rank5
Abstract: The purpose of this study was to evaluate the number of canals and isthmuses obturated after Cr, Er: YSGG laser treatment. Fifty-two canals were instrumented to a size 40 Profile 0.06 file combined with RC-Prep and sodium hypochlorite, or sterile water. The teeth were divided into 3 groups: (I) canals were flooded with 17% ethylenediaminetetraacetic acid for 3 minutes, (II) canals treated with the laser for 40 seconds, and (III) received no further treatment. Obturation was done with System B and Obtura III and AH Plus sealer. The specimens were rendered transparent and evaluated for the number of canals/isthmuses obturated. The data were analyzed by Kruskal-Wallis test. The means ± standard deviations for the groups were 17% ethylenediaminetetraacetic acid (1.14 ± 0.8), laser (2.14 ± 0.7), and control (0.4 ± 0.8). Under the conditions of this study, Cr, Er: YSGG treatment resulted in a statistically significant greater number of canals/isthmuses obturated (P < .001).
Clean / Disinfect DOI   Wang, Q., Zhang, C.F. and Yin, X.Z. Evaluation of the Bactericidal Effect of Er,Cr:YSGG, and Nd:YAG Lasers in Experimentally Infected Root Canals Journal of Endodontics
Vol. 33(7), pp. 830-832 
2007 rank3
Abstract: The aim of this study was to evaluate the bactericidal effect of the Er,Cr:YSGG laser and the Nd:YAG laser in experimentally infected root canals. Sixty single-rooted teeth with straight canals were selected. After preparation and sterilization, the specimens were inoculated with Enterococcus faecalis for 3 weeks. After irradiation by lasers, the number of bacteria in each root canal was examined. The Er,Cr:YSGG laser gave a reduction of 77% after irradiation at 1 W and 96% at 1.5 W, but there was no significant difference (p > 0.05). The Nd:YAG laser gave a reduction of 97% at 1 W and 98% at 1.5 W, and there was no significant difference (p > 0.05). Compared with the Er,Cr:YSGG laser, the Nd:YAG laser is more effective (p < 0.05). In conclusion, both lasers systems have a significant bactericidal effect in infected root canals, and the Nd:YAG laser is more effective than the Er,Cr:YSGG laser. ?? 2007 American Association of Endodontists.
Endo URL  Wang, X., Ishizaki, N.T., Suzuki, N., Kimura, Y. and Matsumoto, K. Morphological Changes of Bovine Mandibular Bone Irradiated by Er,Cr:YSGG Laser: An in Vitro Study Journal of Clinical Laser Medicine & Surgery
Vol. 20(5), pp. 245-50 
2002 rank4
Abstract: OBJECTIVE:
The purpose of this study was to investigate the morphological changes of bovine mandibular bone following Er,Cr:YSGG laser irradiation in different methods in vitro.
BACKGROUND DATA:
Recently, an erbium, chromium/yttrium, scandium, garmet (Er,Cr:YSGG) laser device that emits a laser beam at the wavelength of 2.78 micro m was introduced. This type of infrared laser proved to ablate dental hard tissues effectively. However, the different effects of bone ablation by this laser in different irradiation methods were still unknown.
MATERIALS AND METHODS:
Adult bovine mandibular bones were cut into 24 small pieces, 3-4 cm in length. The parameters of Er,Cr:YSGG laser irradiation were as follows: wavelength was 2.78 micro m, pulse duration was 140-200 micro sec, repetition rate was 20 pulse/sec, power was 4 W, spot size was 1.26 x 10(-3) mm(2), and energy density was 160 J/cm(2). Irradiation methods were different in four groups (six specimens in each group): group A, fixed position and contact mode; group B, fixed position and noncontact mode; group C, nonfixed position and contact mode; and group D, nonfixed position and noncontact mode.
RESULTS:
Ablation depth in group A was significantly greater than in group B (p < 0.01). In group A, thermal damage was apparent. In group B, C, and D, thermal damage was minimal.
CONCLUSION:
Er,Cr:YSGG laser allows for precise surgical bone cutting and ablation with minimal thermal damage to adjacent tissue. Irradiation in different methods may achieve different ablation rates and thermal damage.
Apicoectomy, Endo DOI   Winik, R., Araki, Â.T., Negrão, J.A.A., Bello-Silva, M.S. and Lage-Marques, J.L. Sealer penetration and marginal permeability after apicoectomy varying retrocavity preparation and retrofilling material Brazilian Dental Journal
Vol. 17(4), pp. 323-327 
2006 rank2
Abstract: Apicoectomy failure is generally related to inappropriate marginal sealing of the retrocavity, which allows percolation of microorganisms and their products from root canal system to periapex. This study evaluated tubular penetration of canal sealers and marginal permeability after retrocavity irradiation with Er;Cr:YSGG laser and retrofilling with MTA or cyanoacrylate. Twenty-two single-rooted teeth were decoronated and endodontically treated, their apical 3 mm were resected and the root ends were retroprepared with a low-speed bur. Twenty roots were randomly assigned to 4 groups (n=5): GI and GII--retrofilling with MTA and cyanoacrylate, respectively; GIII and GIV--retrocavity irradiation with Er;Cr:YSGG laser (2.78 microm, 4 W, 20 Hz, 70.8 J/cm(2)) and retrofilling with MTA and cyanoacrylate, respectively. The remaining 2 roots served as positive and negative controls. The analysis of rhodamine B dye infiltration (p=0.05) demonstrated that laser irradiation and MTA retrofilling presented significantly higher permeability rates (p<0.05). Retrofilling with cyanoacrylate showed significantly lower permeability, either when laser was used or not on retrocavity. SEM analysis depicted more cyanoacrylate penetration through dentinal tubules when compared to MTA, suggesting a more efficient marginal sealing. Based on these results, it may be concluded that cyanoacrylate provided a less permeable retrofilling regardless of the retropreparation method, suggesting a more favorable condition to the establishment of the periapical healing.
Clean / Disinfect DOI URL  Yamazaki, R., Goya, C., Yu, D.G., Kimura, Y. and Matsumoto, K. Effects of erbium,chromium:YSGG laser irradiation on root canal walls: a scanning electron microscopic and thermographic study. Journal of endodontics
Vol. 27(1), pp. 9-12 
2001 rank3
Abstract: The present study evaluates the morphological changes in root canal walls and temperature changes at root surfaces as a result of intracanal irradiation by erbium,chromium:YSGG laser under various conditions in vitro. Sixty single-rooted human teeth were examined. Root canals were prepared, and laser irradiation was performed using an optic fiber at output powers ranging from 1 to 6 W with or without water spray cooling. Specimens were evaluated by stereoscopy, scanning electron microscopy, and thermography. Carbonization and cracks were observed in all samples irradiated without cooling, whereas little or no carbonization and no smear layer or debris were observed in samples irradiated with cooling. Maximum temperature rise at irradiation without cooling was above 37 degrees C, whereas that at irradiation with cooling was 8 degrees C. Results of the present study indicate that erbium,chromium:YSGG laser irradiation with water spray cooling is a useful method for removal of smear layer and debris from root canals.
Clean / Disinfect DOI   Yavari, H.R., Rahimi, S., Shahi, S., Lotfi, M., Barhaghi, M.H.S., Fatemi, A. and Abdolrahimi, M. Effect of Er,Cr:YSGG laser irradiation on Enterococcus faecalis in infected root canals. Photomedicine and laser surgery
Vol. 28 Suppl 1, pp. S91-S96 
2010 rank3
Abstract: Objective: The purpose of this study was to investigate the eradication of Enterococcus faecalis by high-power settings of Er, Cr:YSGG laser irradiation in root canals of extracted teeth. Background Data: The bacteria entering the root canal system invade dentinal tubules, resulting in persistent infections in root canals due to limited penetration of irrigation solutions into the dentinal tubules. The antibacterial effects of different lasers have been investigated in previous studies. Materials and Methods: Sixty newly extracted maxillary central incisors were enlarged chemomechanically and sterilized after removal of the smear layer. Root canals were inoculated with E. faecalis, and bacteria were incubated in root canals for 48 h. Samples were randomly divided into four groups, each containing 15 teeth. One group was considered as control with no intervention. Two groups were irradiated with 2- and 3-W output powers of Er, Cr:YSGG laser for 16 s. In the last group, the canals were irrigated with 1% sodium hypochlorite for 20 min. Results: In the laser groups at 2- and 3-W powers, the number of bacteria was reduced 2.4% and 1.53%, respectively, compared with the controls. No significant differences were found between the two laser groups (p > 0.05). The canals irrigated with 1% NaOCl solution demonstrated no bacterial growth. Conclusions: According to the results of the present study, 2- and 3-W powers of Er, Cr:YSGG laser have antibacterial effects on E. faecalis in root canals of infected teeth; however, the effect is less remarkable than that of NaOCl solution.
Clean / Disinfect DOI URL  Zhu, L., Tolba, M., Arola, D., Salloum, M. and Meza, F. Evaluation of effectiveness of Er,Cr:YSGG laser for root canal disinfection: theoretical simulation of temperature elevations in root dentin. Journal of biomechanical engineering
Vol. 131(7), pp. 071004 
2009 rank2
Abstract: Erbium, chromium: yttrium, scandium, gallium, garnet (Er,Cr:YSGG) lasers are currently being investigated for disinfecting the root canal system. Prior to using laser therapy, it is important to understand the temperature distribution and to assess thermal damage to the surrounding tissue. In this study, a theoretical simulation using the Pennes bioheat equation is conducted to evaluate how heat spreads from the canal surface using an Er,Cr:YSGG laser. Results of the investigation show that some of the proposed treatment protocols for killing bacteria in the deep dentin are ineffective, even for long heating durations. Based on the simulation, an alternative treatment protocol is identified that has improved effectiveness and is less likely to introduce collateral damage to the surrounding tissue. The alternative protocol uses 350 mW laser power with repeating laser tip movement to achieve bacterial disinfection in the deep dentin (800 microm lateral from the canal surface), while avoiding thermal damage to the surrounding tissue (T<47 degrees C). The alternative treatment protocol has the potential to not only achieve bacterial disinfection of deep dentin but also shorten the treatment time, thereby minimizing potential patient discomfort during laser procedures.