Root surface treatment using diode laser in delayed tooth replantation: radiographic and histomorphometric analyses in rats.

UNLABELLED: BACKGROUND AIM: The aim of this study was to evaluate, by radiographic and histomorphometric analyses, the effects of high-power diode laser irradiation on the root surfaces of delayed replanted rat teeth. MATERIAL AND METHODS: Maxillary right incisors were extracted from 60 Wistar rats and kept dry for 60 min. Subsequently, the root canals were prepared and filled with calcium hydroxide paste. According to the root surface treatment before the replantation, the teeth were assigned to four groups (n = 15): G1 (negative control) - no root surface treatment; G2 (positive control) - treated with 2% sodium fluoride solution; G3 - irradiated with a high-power diode laser (810 nm, continuous mode, 1.0 W, 30 s); and G4 - irradiated with a diode laser using the same parameters as those used for G3 but in pulsed mode. The rats were euthanized after 15, 30, and 60 days of replantation. The specimens were digitally radiographed and processed for histomorphometric analysis to determine the average root resorption areas and to evaluate the histological events. RESULTS: The percentage of root resorption was in the following order: G1 > G2 > G4 > G3. Both histomorphometric and radiographic analyses showed significantly lower means (P < 0.05) of the occurrence of root resorption in the irradiated groups (G3 and G4) when compared to the control groups (G1 and G2). Replacement resorption and ankylosis were observed in histological sections only after 30 and 60 days; however, such events were not observed in G3. CONCLUSION: Root surface treatments with high-powered diode laser irradiation prior to delayed replantation reduced the occurrence of external root resorption compared to no treatment or sodium fluoride treatment at up to 60 days.

Calcitonin, sodium alendronate and high intensity laser in the treatment of traumatized teeth: a preliminary study.

The aim of this study was to evaluate the influence of erbium:yttrium-aluminum-garnet (Er:YAG) laser compared with traditional treatment on dentin permeability to calcitonin and sodium alendronate. Forty bovine roots were sectioned and divided into eight groups. Groups 1 and 2 (G1/G2) were immersed in saline solution; G1T/G2T were immersed in ethylene diamine tetra-acetic acid plus sodium lauryl ether sulfate (EDTA-T) and sodium hypochlorite (NaOCl); G1I/G2I were irradiated with Er:YAG laser (2.94 microm, 6 Hz, 40.4 J/cm(2)); G1TI/G2TI were immersed in EDTA-T, NaOCl and subjected to Er:YAG irradiation. After 4 h the radioactivity of the saline solution was measured. Statistical analysis revealed a significant difference (P < 0.05) when the groups treated with EDTA-T and NaOCl followed by Er:YAG laser irradiation were compared with the groups treated with EDTA-T only and with the groups that received no treatment. Er:YAG laser associated with traditional procedures significantly increased the diffusion of calcitonin and sodium alendronate through dentin. All groups showed calcitonin and sodium alendronate diffusion.

Apicoectomy of Perforated Root Canal Using Bioceramic Cement and Photodynamic Therapy.

Root perforation is a common endodontic accident. Its management depends mainly on root canal disinfection and sealing the perforation area by preventing any communication with the periodontium to prevent recontamination. A patient was referred to treat root perforation due to a previous treatment of tooth #22. The diagnosis was symptomatic periapical periodontitis, and the treatment plan was to retreat the root canal of #22 and make a surgical intervention (apicoectomy) associated with antimicrobial photodynamic therapy as a complementary technique. Five mineral oxides (5MO) cement was used as a root-end filling material. The procedures were performed in two sessions and controlled in two visits (after 30 days and 12 months). A bone neoformation was observed at the periapical area of tooth #22. 5MO bioceramic cement was effective in inducing the repair of the periapical lesion and had the ability to seal the exposed periapical area of the tooth. Its success depended mainly on root canal and surgical site disinfection.

Treatment options for teeth with open apices and apical periodontitis.

Three clinical cases involving teeth with open apices and apical periodontitis were treated using different protocols. The first case was managed with intracanal calcium hydroxide paste for 12 months before obturation with gutta-percha and sealer. In the second case, an apical plug of mineral trioxide aggregate (MTA) was used before obturation with gutta-percha and sealer and treatment was completed during 2 appointments. In the third case, the tooth, which had a divergent root canal system, was completely obturated with MTA and treatment was also completed over 2 appointments. In all 3 cases, signs of bone healing were observed after treatment.

Ozone therapy in medicine and dentistry.

AIM: The purpose of this review is to present the potential for the incorporation of ozone therapy into the practice of dentistry. BACKGROUND: Ozone gas has a high oxidation potential and is 1.5 times greater than chloride when used as an antimicrobial agent against bacteria, viruses, fungi, and protozoa. It also has the capacity to stimulate blood circulation and the immune response. Such features justify the current interest in its application in medicine and dentistry and have been indicated for the treatment of 260 different pathologies. It can be used for the treatment of alveolitis as a replacement for antibiotic therapy, as a mouthwash for reducing the oral microflora, as well as the adherence of microorganisms to tooth surfaces. Ozone has been shown to stimulate remineralization of recent caries-affected teeth after a period of about six to eight weeks. CONCLUSION: The future of ozone therapy must focus on the establishment of safe and well-defined parameters in accordance with randomized, controlled trials to determine the precise indications and guidelines in order to treat various medical and dental pathologies. Scientific support, as suggested by demonstrated studies, for ozone therapy presents a potential for an atraumatic, biologically-based treatment for conditions encountered in dental practice.

Er:Yag laser irradiation of the microbiological apical biofilm.

One problem in cases of healing-resistant periapical lesions is to eradicate the contamination at the periapical area. This contamination is due to the microbiological biofilm formed by microorganisms and their subproducts lodged in apical third of the root, on both cementum and dentin surface. Paraendodontic surgery consists of the mechanical removal of harmful agents to promote healing and periapical health. The purpose of this study was to assess the results of Er:YAG laser irradiation on the apical root third of newly extracted teeth to eliminate microbial contamination on root apex surface. Apical irradiation was performed with an Er:YAG laser device using an experimental contact tip, at 100 mJ, 10 Hz, 1 W, 39 J/cm(2), 3 times on the target area. SEM analysis showed the elimination of part of the irradiated cementum and the formation of small roughened without exposing the subjacent dentin. Vaporization of the remaining periodontal tissue and removal of microbiological apical biofilm (MAB) were also observed on the irradiated areas. Under the tested conditions and based on the findings of this study, Er:YAG laser may be considered effective for removal of microbiological apical biofilm.

Sealer penetration and marginal permeability after apicoectomy varying retrocavity preparation and retrofilling material.

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.

Ozone therapy as an adjuvant for endondontic protocols: microbiological - ex vivo study and citotoxicity analyses.

OBJECTIVES: This study evaluated the antimicrobial efficacy of ozone therapy in teeth contaminated with Pseudomonas aeruginosa, Enterococcus faecalis, and Staphylococcus aureus using a mono-species biofilm model. Parallel to this, the study aimed to evaluate the cytotoxicity of ozone for human gingival fibroblasts. Material and Methods: One hundred and eighty single-root teeth were contaminated with a mono-species biofilm of Enterococcus faecalis, Pseudomonas aeruginosa, and Staphylococcus aureus. Groups were formed: Group I - control; Group II - standard protocol; Group III - standard protocol + ozone gas at 40 µg/mL; and Group IV - standard protocol + aqueous ozone at 8 µg/mL. In parallel, human gingival fibroblasts were submitted to the MTT test. Cells were plated, then ozone was applied as follows: Group I (control) - broth medium; Group II - aqueous ozone at 2 µg/mL; Group III - aqueous ozone at 5 µg/mL; and Group IV - aqueous ozone at 8 µg/mL. Data were submitted to the Kruskal Wallis test and Bonferroni post hoc analyses to assess microbiology and cytotoxicity, respectively (p<0.05%). RESULTS: The results revealed antimicrobial efficacy by Group IV with no CFU count. The cytotoxicity assay showed Groups III and IV to be the most aggressive, providing a decrease in cell viability at hour 0 from 100% to 77.3% and 68.6%, respectively. Such a decrease in cell viability was reverted, and after 72 hours Groups III and IV provided the greatest increase in cell viability, being statistically different from Groups I and II. CONCLUSION: According to the applied methodology and the limitations of this study, it was possible to conclude that ozone therapy improved the decontamination of the root canal ex vivo. Ozone was toxic to the cells on first contact, but cell viability was recovered. Thus, these findings suggest that ozone might be useful to improve root canal results.

In vitro evaluation of the effects of the interaction between irrigating solutions, intracanal medication and Er:YAG laser in dentin permeability of the endodontic system.

The purpose of this study was to evaluate in vitro the effects of different associations between irrigating solutions (EDTA-T and citric acid), intracanal medicament (NDP), and Er:YAG laser irradiation on dentin permeability. Fifty-one extracted single-rooted teeth were instrumented and divided into seven groups. Groups GI and GII had final irrigation with a demineralizing solution only (EDTA-T and citric acid, respectively). Groups GIII and GIV had final irrigation with EDTA-T and citric acid, respectively, plus an association of irrigating solution and Er:YAG laser. Groups GV and GVI had final irrigation with EDTA-T and citric acid, respectively, plus an association of intracanal medication and Er:YAG laser. Group GVII (control group) had final irrigation with distilled water. All root canals were filled with NDP associated with rhodamine B dye. After the experimental period, the samples were transversely cut into six 2.0 mm thick slices for subsequent reading using the ImageLab software. Analysis of the results allowed us to conclude that there were statistically significant differences (p < 0.05) between the groups as to the penetration of the dye-intracanal medication solution. Groups III and IV presented smaller values of dentinal permeability when compared to the other groups. The best results were obtained with the interaction between a demineralizing irrigating solution and the association of intracanal medicament and laser Er:YAG (groups V and VI). In these groups the observed penetration of the intracanal medicament plus dye solution in the apical third was, on average, 29% greater than in the other groups.

Evaluation of the permeability of the furcation area of deciduous molars conditioned with Er:YAG laser and cyanoacrylate.

The purpose of this study was to evaluate in vitro the dentin permeability of the deciduous pulp chamber floor after employing 2-octyl cyanoacrylate and Er:YAG laser. Twenty four deciduous molars were used, divided into four groups. After chemical-surgical preparation each group received a different treatment: Group 1 - control, without treatment; Group 2 - the floor of the pulp chamber was covered with a fine layer of 2-octyl cyanoacrylate; Group 3 - the floor of the pulp chamber was irradiated with Er:YAG laser (250 mJ, 10 Hz for 30 seconds, 80 J of energy and 320 pulses), and covered with a fine layer of 2-octyl cyanoacrylate; and Group 4 - the floor of the pulp chamber was irradiated with Er:YAG laser set at the parameters already described. After that the specimens received application of 0.5% methylene blue, for 15 minutes. The teeth were cut, photographed, and the digitalized images were analyzed using the ImageLab program. The results obtained were submitted to statistical analysis. Group 4 (Er:YAG) presented the largest averages in percentage of dye penetration area (19.5%), followed by Group 1 (11.1%), Group 3 (1.4%) and Group 2 (0.2%). The experimental model allowed to conclude that the specimens conditioned with 2-octyl cyanoacrylate (Group 2) and Er:YAG laser associated to 2-octyl cyanoacrylate (Group 3) presented a decrease in permeability, and the specimens treated with Er:YAG laser (Group 4) presented an increase in permeability of the analyzed area.

Effect of dental adhesives on the exudative phase of the inflammatory process in subcutaneous tissue of rats.

The vascular changes in the subcutaneous connective tissue of rats induced by dentin bonding systems (one step) was studied and compared to those induced by saline solution (negative control) and Furacin (positive control), during the exudative phase of the inflammatory process. Twenty mg/kg of Evan's blue were injected intravenously in the vein of the rats' penises; 0.1 ml of each substance tested was inoculated in the subcutaneous tissue. After a 3 hour period the animals were sacrificed and their skins were excised and punched out with a standard steel 2.5 cm in diameter. The specimens were immediately immersed in 8 ml of formamide and taken to a double boiler for 72 hours at 37 C, to remove the dye. The liquid containing the overflowed dye was filtered, analyzed in the spectrophotometer (620 nm) and classified according to the criteria established by Nagem-Filho, Pereira (1976). After statistical analysis, the irritative potential of the substances was ranked as follows: Furacin (severe) > Single Bond and Bond 1 (moderate - no significant differences between the dentin bonding systems tested) > saline solution (not significant as regards the irritation degree).

[Spectrophotometric and visual analysis of internal dental bleaching utilizing laser and heat as catalyzing sources]. / Análise espectrofotométrica e visual do clareamento dental interno utilizando laser e calor como fonte catalisadora.

This experiment aimed at evaluating, in vitro, the chromatic alteration of dental crowns submitted to internal bleaching. Color alterations were evaluated by means of spectrophotometric analysis and visual observation, at the following experimental phases: initial reading (LI), after-darkening reading (LE), immediate after-bleaching reading (LC), bleaching checked after 15 days (LC15) and after 30 days (LC30). After finding the values of L* (luminosity), a* and b* (shade and saturation), which made it possible to quantify the chromatic alterations of the specimens, color differences (deltaE ) were assessed by means of the CIE Lab Program. The statistical analysis of the results did not reveal any significant difference between conventional bleaching and bleaching activated by Er:YAG laser. No statistical difference was observed between the results after 15 and 30 days, for both experimental groups.

SEM analysis of defects and wear on Ni-Ti rotary instruments.

SEM analysis of endodontic instruments from a Ni-Ti rotary system was assessed, before and after using them, considering their defects and deformations. Twenty Twisted File®, BioRaCe®, Mtwo®, and EndoWave® instruments were micrographed at 190× magnification. The files were washed and micrographed again to view alterations as to the presence or absence of irregular edges, grooves, microcavities, and scraping. Simulated root canal preparations were performed using these instruments. The instruments were cleaned and received a microscopic analysis after being used five times. After analysis tests were tested using Fisher's exact test and Kappa to evaluate the concordance among examiners. There was a statistically significant difference with respect to deformations between Twisted File® and other instruments (p < 0.05). There was no statistically significant difference in strains between the other groups (p > 0.05). All Twisted File® instruments showed the same defects; however damage were lower than those found in BioRace® and Mtwo®. The Endowave® did not show the same defects. In accordance with the data we conclude that the presence of defects was higher in Twisted File® instruments as the instruments and BioRace® Mtwo® brand, the defect rate was smaller and Endowave® instruments had no defects. Regarding the presence of wear after five uses among the groups all instruments showed changes in their cutting blades.

Effect of chemical substances in removing methylene blue after photodynamic therapy in root canal treatment.

BACKGROUND AND OBJECTIVE: The disadvantage of photodynamic therapy (PDT) is in the photosensitizing agents that may stain the tooth structure. There is no register of PDT studies evaluating protocols to minimize that concern. The present study evaluated the efficiency of chemical adjuncts in methylene blue dye (MB) removal after PDT. MATERIALS AND METHODS: Forty single-rooted teeth, after root canal preparation, were filled with 0.01% MB for 5 min, and irradiated with diode laser 660 nm at 40 mW for 240 sec (total energy 9.6 J). The specimens were divided into four groups (n = 10), according to the chemical adjuncts used for dye removal: (a) 2.5% sodium hypochlorite (NaOCl); (b) 2.5% NaOCl + Endo-PTC cream; (c) 70% ethyl alcohol and (d) saline (control). The crowns were sectioned and fixed in a device. Photographs were taken before the PDT (T0), immediately after (T1) and upon dye removal (T2). The chromatic alterations were evaluated using Adobe Photoshop and K values were determined in four fixed points of each crown. RESULTS: K values (dental staining) increased in all groups when comparing T0 and T1. The effectiveness of the tested adjuncts was, in decreasing order: G1 (-3.11) > G2 (-2.97) > G3 (-1.28) > G4 (-1.19), not observing significant statistical differences (p < 0.05) between G1 and G2 and also between G3 and G4. CONCLUSIONS: Protocols to remove photosensitizing dyes should be applied after PDT in order to minimize dental stain. The protocols tested in this study by using 2.5% NaOCl, associated or not with Endo-PTC cream, were effective in avoiding tooth staining caused by MB during PDT.

Effect of nitric oxide inhibitor and donor substances on the inflammatory process caused by endodontic irrigants.

UNLABELLED: Nitric oxide (NO) has been considered a key molecule in inflammation. OBJECTIVE: The aim of this study was to evaluate the effect of treatment with L-NAME and sodium nitroprussiate, substances that inhibit and release NO, respectively, on tissue tolerance to endodontic irrigants. MATERIAL AND METHODS: The vital dye exudation method was used in a rat subcutaneous tissue model. Injections of 2% Evans blue were administered intravenously into the dorsal penial vein of 14 male rats (200-300 g). The NO inhibitor and donor substances were injected into the subcutaneous tissue in the dorsal region, forming two groups of animals: G1 was inoculated with L-NAME and G2 with sodium nitroprussiate. Both groups received injections of the test endodontic irrigants: acetic acid, 15% citric acid, 17% EDTA-T and saline (control). After 30 min, analysis of the extravasated dye was performed by light absorption spectrophotometry (620 nm). RESULTS: There was statistically significant difference (p<0.05) between groups 1 and 2 for all irrigants. L-NAME produced a less intense inflammatory reaction and nitroprussiate intensified this process. CONCLUSIONS: Independently of the administration of NO inhibitors and donors, EDTA-T produced the highest irritating potential in vital tissue among the tested irrigating solutions.

Ozone therapy as an adjuvant for endondontic protocols: microbiological – ex vivo study and citotoxicity analyses

ABSTRACT Objectives This study evaluated the antimicrobial efficacy of ozone therapy in teeth contaminated with Pseudomonas aeruginosa, Enterococcus faecalis, and Staphylococcus aureus using a mono-species biofilm model. Parallel to this, the study aimed to evaluate the cytotoxicity of ozone for human gingival fibroblasts. Material and Methods: One hundred and eighty single-root teeth were contaminated with a mono-species biofilm of Enterococcus faecalis, Pseudomonas aeruginosa, and Staphylococcus aureus. Groups were formed: Group I – control; Group II – standard protocol; Group III – standard protocol + ozone gas at 40 µg/mL; and Group IV – standard protocol + aqueous ozone at 8 µg/mL. In parallel, human gingival fibroblasts were submitted to the MTT test. Cells were plated, then ozone was applied as follows: Group I (control) – broth medium; Group II – aqueous ozone at 2 µg/mL; Group III – aqueous ozone at 5 µg/mL; and Group IV – aqueous ozone at 8 µg/mL. Data were submitted to the Kruskal Wallis test and Bonferroni post hoc analyses to assess microbiology and cytotoxicity, respectively (p<0.05%). Results The results revealed antimicrobial efficacy by Group IV with no CFU count. The cytotoxicity assay showed Groups III and IV to be the most aggressive, providing a decrease in cell viability at hour 0 from 100% to 77.3% and 68.6%, respectively. Such a decrease in cell viability was reverted, and after 72 hours Groups III and IV provided the greatest increase in cell viability, being statistically different from Groups I and II. Conclusion According to the applied methodology and the limitations of this study, it was possible to conclude that ozone therapy improved the decontamination of the root canal ex vivo. Ozone was toxic to the cells on first contact, but cell viability was recovered. Thus, these findings suggest that ozone might be useful to improve root canal results.

Effectiveness of photodynamic therapy against Enterococcus faecalis, with and without the use of an intracanal optical fiber: an in vitro study.

BACKGROUND AND OBJECTIVE: Photodynamic therapy (PDT) is a new technique introduced in endodontics that combines the action of a photosensitizer (dye) and a low intensity light source. Currently, there are no PDT studies evaluating the microbial disinfection of root canals in order to compare the effects of light delivery systems in the photosensitizer activation. The aim of this study was to evaluate the PDT effectiveness in reducing Enterococcus faecalis, with and without the aid of an intracanal optical fiber. METHODS: Extracted single-rooted teeth were selected, instrumented, inoculated with E. faecalis and divided into six groups: one control group (untreated), one conventionally-treated group (1% NaOCl irrigation) and four PDT-treated groups. Irradiation (diode laser) was performed with (OF) or without an intracanal optical fiber (NOF) using two different irradiation times: 1 min and 30 sec (IT(90)) or 3 min (IT(180)). Samples were collected before and after testing procedures and CFU/mL was determined. RESULTS: The greatest reduction of E. faecalis (99.99%) was achieved with irrigation with 1% NaOCl. PDT also significantly reduced E. faecalis in the following decreasing order: OF/IT(180), NOF/IT(180), OF/IT(90) and NOF/IT(90), with no significant statistical difference among the groups. CONCLUSIONS: These results suggest that PDT was effective against E. faecalis, regardless of the use of an intracanal optical fiber.

Time- and concentration-dependent cytotoxicity of antibiotics used in endodontic therapy.

OBJECTIVE: New drugs have to be assessed in endodontic therapy due to the presence of microorganisms resistant to therapeutic procedures. Thus, this study evaluated the time- and concentration-dependent cytotoxicity of different antibiotics used in endodontic therapy. MATERIAL AND METHODS: Human gingival fibroblasts were treated and divided into the following experimental groups: Group I - control; Group II - ciprofloxacin hydrochloride; Group III - clyndamicin hydrochloride; and Group IV - metronidazole. Each drug was used at concentrations of 5, 50, 150, and 300 mg/L for 24, 48, 72, and 96 h. Cytotoxicity was evaluated by the MTT assay [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] and spectrophotometric reading of ELISA plates. The results were analyzed by BioEstat 4.0 software using Kruskal-Wallis and Dunn's tests at a significance level of 5%. Cell viability was assessed for the different concentrations and times. RESULTS: All drugs presented dose-dependent cytotoxicity. Concentrations of 5 and 50 mg/L produced viable fibroblasts at all experimental times in all groups. CONCLUSIONS: Cell viability at 24 h was greater than in the other experimental times. Comparison between the same concentrations of antibiotics at different times showed that metronidazole presented the highest cell viability at 72 and 96 h compared to the other antibiotics, whereas clyndamicin hydrochloride showed higher cell viability at 72 h than ciprofloxacin hydrochloride.

Attachment of cultured fibroblasts and ultrastructural analysis of simulated cervical resorptions treated with high-power lasers and MTA.

OBJECTIVE: The present study evaluated the fibroblast attachment and the morphologic changes of simulated cervical root resorptions after irradiation with high-power lasers and the use of mineral trioxide aggregate (MTA). STUDY DESIGN: Standardized cavities were done on the coronal third of 40 single-rooted teeth and assigned into 4 groups according to the treatment applied: (1) untreated control, (2) use of MTA, (3) irradiation with Er:YAG laser (42 mJ, 10 Hz, 10 s), and (4) irradiation with high-power diode laser (1 W, 10 s). Fragments were prepared for SEM analysis: 6 samples of each group were plated with human gingival fibroblasts and 4 samples were used for ultrastructural analysis. RESULTS: The cells' attachment was in decreasing order: G3 > G4 > G1> G2, with statistical differences among all groups (P < .05). The samples irradiated with Er:YAG exhibited roughness on the dentinal surface, no smear layer, and open dentinal tubules; those irradiated with diode laser exhibited a smooth surface, more smear layer, and closed dentinal tubules; and the control group showed high amount of smear layer and closed dentin tubules. CONCLUSIONS: Irradiation with Er:YAG and diode lasers caused morphologic changes on the dentinal surfaces of simulated resorptions that favored cells' adhesion. MTA showed lower biocompatibility than irradiated groups but allowed cells' adhesion.

High-power diode laser in the disinfection in depth of the root canal dentin.

OBJECTIVE: The objective of this study was to evaluate the disinfection degree of dentine caused by the use of diode laser after biomechanical procedures. STUDY DESIGN: Thirty teeth were sectioned and roots were autoclaved and incubated for 4 weeks with a suspension of Enterococcus faecalis. The specimens were randomly divided into 3 groups (n = 10): G1, instrumented with rotary files, irrigated with 0.5% sodium hypochlorite and 17% EDTA-T, and then irradiated by 830-nm diode laser at 3 W; G2, the same procedures as G1 but without laser irradiation; and G3, irrigation with saline solution (control). Dentin samples of each third were collected with carbide burs and aliquots were sowed to count viable cells. RESULTS: The disinfection degree achieved was 100% in G1 and 98.39% in G2, when compared to the control group (G3). CONCLUSION: Diode laser irradiation provided increased disinfection of the deep radicular dentin in the parameters and samples tested.