Maria Isabel Anastacio Faria

Apical microleakage and SEM analysis of dentin surface after 980 nm diode laser irradiation

This study evaluated the effect of 980-nm diode laser on apical microleakage and intraradicular dentin morphology. Roots of 110 mandibular incisors were used in the study: 92 for microleakage test and 18 for scanning electron microscopy (SEM). Roots were randomly assigned to 3 groups according to the irrigating solution (water, NaOCl and NaOCl/EDTA) and were divided into 3 subgroups according to the laser irradiation protocol (without irradiation, irradiated at 1.5 W and irradiated at 3.0 W). Two specimens of each subgroup were prepared for SEM. The remaining roots were filled with AH Plus and gutta-percha. Apical leakage was assessed by ink penetration and data were analyzed statistically by ANOVA and Tukey-Krammer test (α=0.05). SEM analysis showed intensification of changes with increase of laser power as well as variations according to the irrigating solution. Modified smear layer was observed in specimens treated with water and irradiated with laser. Roots irrigated with NaOCl/EDTA had lower levels of infiltration (0.17 ± 0.18 mm) differing significantly (p<0.05) from those of roots irrigated with water (0.34 ± 0.30 mm), but similar (p>0.05) to those irrigated with NaOCl (0.28 ± 0.29 mm). Non-irradiated roots had lower levels of infiltration (0.10 ± 0.14 mm), differing (p<0.05) from those irradiated at 1.5 W (0.32 ± 0.22 mm) and 3.0 W (0.37 ± 0.32 mm). The 980 nm diode laser modified dentin morphology and increased apical microleakage.

Tensile Strength of Glass Fiber Posts Submitted to Different Surface Treatments

The aim of this in vitro study was to evaluate the tensile strength of glass fiber posts submitted to different surface treatments. Forty-eight maxillary canines had their crowns sectioned and root canals endodontically treated. The roots were embedded in acrylic resin and distributed into 3 groups according to the surface treatment: Group I: the posts were treated with silane agent for 30 s and adhesive; Group II: the posts were cleaned with alcohol before treatment with silane agent and adhesive; Group III: the posts were submitted to conditioning with 37% phosphoric acid for 30 s before treatment with silane agent and adhesive. Each group was divided into 2 subgroups for adhesive polymerization or not before insertion into the canal: A - adhesive was not light cured and B - adhesive was light cured. All posts were cemented with Panavia F and the samples were subjected to tensile strength test in a universal testing machine at crosshead speed of 1 mm/min. Data were submitted to one-way ANOVA and Tukeys test at 5% significance level. There was statistically significant difference (p<0.01) only between group GIII-B and groups GI-A and GI-B. No significant difference was found among the other groups (p>0.05). It was concluded that the products used for cleaning the posts influenced the retention regardless of adhesive light curing.

Endodontic treatment of dental formation anomalies

Purpose: Dental fusion is defined as the union of two dental germs at some stage of their development. The aim of this article is to report the endodontic treatment of two clinical cases of dental fusion. Case description: In the first case, the patient was referred by an orthodontist for endodontic treatment of tooth 12, which was fused to 13. Surgical separation and later replacement of the involved elements in the dental arch was indicated. In the second case, the patient sought dental attendance due to spontaneous pain. In the radiographic exam, gemination in tooth 11 and fusion of 21 with a supernumerary tooth was observed. The fused teeth were endodontically treated, and patients were referred to other dental specialties to reestablish esthetics and function. Conclusion: The dentist must be able to diagnose, differentiate and treat these dental anomalies adequately, with the goal of maintaining patients’ oral health.

In vitro evaluation of gutta-percha dissolution ability of different solvents

Introduction: The removal of the filling material during the Endodontic retreatment is essential, so a better action of solvents on the gutta-percha is desired. Objective: To evaluate in vitro the gutta-percha dissolution ability of different solvents. Material and methods: Four solvents (xylol, eucalyptol, citrol, and orange oil) were applied on gutta-percha points, which had been later submitted to the weight loss analysis at 2, 5, and 10 minutes. For each solvent, 30 size #60 main cones were used, divided into three groups. Distilled water was used as control group. The statistical test applied was Kruskal-Wallis. Results: No statistically significant difference occurred among the solvents at 2 minutes (p > 0.05); however, during this period, citrol had the best performance. In longer time intervals, the xylol showed differences compared to eucalyptol at 5 minutes and to eucalyptol and citrol at 10 minutes (p < 0.05). The worst results were found for eucalyptol. Conclusion: This xylol was the solvent with improved ability to dissolve the gutta-percha points, with better results at longer time periods.

Avaliação da capacidade de dissolução de tecido pulpar bovino pelo hipoclorito de sódio em diferentes concentrações

Introductionsodium hypochlorite is the most used auxiliary chemical substance in endodontic treatment due to its antimicrobial action and its ability to dissolve organic matter.Objectivethe objective of the present study was to compare the dissolution speed of bovine pulp tissue fragments in different concentrations of sodium hypochlorite.Material and methodbovine pulp tissue fragments, with determined weight, were immersed in Becker bottles filled with 20 ml of sodium hypochlorite and placed in an incubator/stirrer. Concentrations of 1%, 2.5% and 5%, with pH of 11, at 36°C. Each sample was evaluated visually during the stirring, with the aid of magnifying glass, until its complete dissolution. The speed of dissolution of each fragment was determined in milligrams per minute and by the average speed of each group was analyzed by Kruskal-Wallis and Dunns Multiple statistical methods.ResultThere were statistically significant differences between the concentration of 1%, with the lowest speed, and others.ConclusionThe dissolution speed of sodium hypochlorite of tested concentrations, becomes faster with the increasing of the concentration.