João Vicente Baroni Barbizam

Influence of endodontic irrigants on bond strength of a self-etching adhesive

The aim of this in vitro study was to evaluate the bond strength of a self-etching adhesive system to dentine irrigated with sodium hypochlorite (NaOCl), chlorhexidine solution (CX) and ethylene diamine tetra acetic acid (EDTA) by microtensile testing. Sixty human third molars were sectioned 3 mm below the occlusal level and then randomly divided into six groups: G1(control), without irrigant solution; G2, 1% NaOCl; G3, 1% NaOCl followed by the application of 17% EDTA; G4, 2% CX; G5, 2% CX followed by the application of 17% EDTA and G6, 17% EDTA. The specimens received the self-etching adhesive system were restored with composite resin, then sectioned and trimmed to obtain four hourglass-shaped slabs from each tooth. The specimens were submitted to the microtensile test in a Universal Testing Machine at a crosshead speed of 0.5 mm min(-1) until fracture. The results were submitted to statistical analysis by anova /Newman-Keuls. The means and standard deviations (MPa) were: G1, 26.88 (±3.81); G2, 19.08 (±3.89); G3, 18.16 (±2.21); G4, 18.14 (±4.32); G5, 34.30 (±3.32); G6, 13.61 (±1.21). It was concluded that the application of 2% CX followed by the application of 17% EDTA resulted in increasing the bond strength of the self-etching adhesive system to dentine, when compared with the results obtained for the other tested groups.

Bond strength of different endodontic sealers to dentin: push-out test

Objective The aim of this in vitro study was to evaluate the bond strength of different root canal sealers to dentin. Material and Methods Forty extracted single-rooted human teeth were examined and the coronal and middle thirds of the canals were prepared with a 1.50 mm post drill (FibreKor Post System, Pentron). The teeth were allocated in two experimental groups, irrigated with 2.5% NaOCl+17% EDTA or saline solution (control group) and instrumented using Race rotary files (FKG) to a size #40 at the working length. Then, the groups were divided into four subgroups and filled with Epiphany sealer (Group 1), EndoREZ (Group 2), AH26 (Group 3) and Grossmans Sealer (Group 4). After 2 weeks of storage in 100% humidity at 37ºC, all teeth were sectioned transversally into 2-mm-thick discs. Push-out tests were performed at a cross-head speed of 1 mm/min using a universal testing machine. The maximum load at failure was recorded and expressed in MPa. Results Means (±SD) in root canals irrigated with 2.5% NaOCl and 17% EDTA were: G1 (21.6±6.0), G2 (15.2±3.7), G3 (14.6±4.5) and G4 (11.7±4.1).Two-way ANOVA and Tukeys test showed the highest bond strength for the Epiphanys group (p< 0.01) when compared to the other tested sealers. Saline solution decreased the values of bond-strength (p<0.05) for all sealers. Conclusion Epiphany sealer presented higher bond strength values to dentin in both irrigating protocols, and the use of 2.5% NaOCl and 17% EDTA increased the bond strength values for all sealers.

Evaluation of the colour change in enamel and dentine promoted by the interaction between 2% chlorhexidine and auxiliary chemical solutions.

To evaluate the colour change in enamel and dentine, promoted by interaction of 2% chlorhexidine gluconate (CHX) with 5.25% sodium hypochlorite (NaOCl) and 17% ethylenediaminetetraacetic acid (EDTA). Fragments containing enamel and dentine were obtained from the crowns of extracted bovine incisors. Before and after immersion of the samples in the substances, they were evaluated with reference to the colour of the enamel and dentine. The values obtained in numerical scores were subjected to statistical analysis using Wilcoxon test. A colour change in the enamel and dentine in groups treated with CHX gel + NaOCl and CHX gel + NaOCl + EDTA, and a change in colour only in the dentine in groups treated with CHX solution + NaOCl and CHX solution + NaOCl + EDTA. When used prior to NaOCl, CHX has the ability to induce a colour change in dental structures.

Effectiveness of a silicon-based root canal sealer for filling of simulated lateral canals

The purpose of this in vitro study was to evaluate the ability of a silicon-based root canal sealer, compared to zinc oxide and eugenol and an epoxy resin-based sealers, for filling of simulated lateral canals. Thirty extracted single-rooted human teeth were selected, conventional access was made and the working length was established 1 mm from the apical foramen. Three simulated lateral canals, one in each root third (coronal, middle and apical) were prepared in both the mesial and distal surfaces of each tooth using a size 15 reamer adapted to a low-speed handpiece. Each root canal was instrumented using ProTaper rotary files up to file F3 at the working length, and then irrigated with 2.5% NaOCl followed by EDTA. The teeth were assigned to 3 groups (n=10), according to the root canal sealer: Roeko Seal (Group 1), Sealer 26 (group 2) and Grossmans sealer (Group 3). Gutta-percha cold lateral condensation technique was performed in all groups. Postoperative radiographs were taken and the images were projected for evaluation of the quality of lateral canal filling. Data were submitted to statistical analysis by Kruskal Wallis test at 5% significance level. The results showed that Grossmans sealer filled a larger number of lateral canals than Roeko Seal (p<0.05) and Sealer 26 (p<0.01). It may be concluded that Roeko Seal silicone-based root canal sealer was not as effective as the Grossmans sealer for filling of simulated lateral canals. The lateral canals localized in the apical third of the root were more difficult to be filled.

In vitro evaluation of filling of lateral root canals with different filling materials by using digital radiography

PURPOSE: To evaluate the ability of different endodontic systems to fill simulated lateral canals using resources of digital radiography. METHODS: Seventy extracted single-rooted human teeth were selected, the coronal access was performed, and the working length was established 1 mm short of the foramen. Two lateral canals were created, one in the middle third and one at the apical third, in each root canal. After chemo-mechanical preparation the teeth were divided into 7 groups (n=10) according to the filling material used: G1 Epiphany, G2 AH Plus, G3 EndoRez, G4 EndoFill, G5 Endomethasone, G6 Sealapex and G7 Sealer 26. In the G1 Epiphany system, Resilon cones were used. In all other groups gutta-percha cones were used. After seven days of storage, digital radiographs were taken to assess the results. The program DBSWIN measured the total length, in mm, of each lateral canal and the length, in mm, that each filling system was able to obturate the canals. Data were analyzed by ANOVA and Tukeys test at the 5% significance level. RESULTS: The filling system Sealer 26/gutta-percha showed less capacity to fill lateral canals than the other filling systems tested (P 0.05). CONCLUSION: The system Sealer 26/gutta-percha was less effective in the filling of simulated lateral canals.

Effect of endodontic irrigating solutions on the adhesive bond strength to dentin

PURPOSE: To evaluate the bond strength of a total-etching adhesive system to dentin irrigated with 1% sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid 17% (EDTA). METHODS: Thirty human molars were sectioned 3mm below the oclusal surface and were randomly divided into 3 groups (n=10): G1, no treatment (control); G2, 1% NaOCl; G3, NaOCl followed by EDTA. The specimens received the total-etching adhesive system, restored with microhybrid composite resin, sectioned and trimmed to create 4 hourglass-shaped slabs of each tooth. The slabs were tested in microtensile bond strength in a universal testing machine (Emic DL 2000) at a crosshead speed of 0.5 mm/min until fracture. The results were analyzed statistically by ANOVA and Newman-Keuls test. G2 samples were not submitted to the test because they fractured just before testing, and its values were considered zero to the statistical analysis. RESULTS: The means and standard deviations (MPa) were: G1, 8.41 (±3.51); G2, 0.0 (±0.00); G3, 8.47 (±3.53). CONCLUSION: It was concluded that the application of the NaOCl irrigating solution significantly decreased the bond strength values. The use of NaOCl followed by EDTA resulted in bond strength values not statistically different from control group.

In vitro evaluation of radiopacity of different filling materials by resources of digital radiography

Aim: the purpose of this study was to evaluate the radiopacity of different filling materials, using resources of digital radiography in a human tooth model. Methodology: seventy extracted single-rooted human teeth were selected, the coronal access was performed, and the working length was established 1 mm short of the foramen. After chemo-mechanical preparation the teeth were divided into 7 groups (n = 10) according to the filling material used: G1 Epiphany, G2 AH Plus, G3 EndoRez, G4 EndoFill, G5 Endomethasone, G6 Sealapex and G7 Sealer 26. In the G1 Epiphany system, Resilon cones were used; however, in all other groups gutta-percha cones were used. After seven days of storage, digital radiographs were taken to assess the results. To evaluate the radiopacity, the digital software DBSWIN generated a colorimetric graphic for each sample, correlating the color gradient observed in the sample with a corresponding numerical score. The data were statistically analyzed by ANOVA and Tukeys test at 5% significance level. Results: the system Epiphany / Resilon was statistically superior to the AH Plus, EndoRez, Sealapex and Sealer 26 groups associated with gutta-percha in terms of radiopacity (P <0.05). Conclusion: the root canal sealer Epiphany, associated with Resilon cones, showed the highest values of radiopacity.

Mineral trioxide aggregate as an apical plug in infected immature teeth: a case series

OBJETIVO: O objetivo desse artigo e descrever tres casos clinicos de dentes com rizogenese incompleta e necrose pulpar tratados com agregado trioxido mineral (MTA) para obtencao de barreira de selamento apical. DESCRICAO DOS CASOS: Todos os casos relatados apresentaram interrupcao da formacao radicular como consequencia da necrose pulpar. Os canais foram instrumentados utilizando gel de clorexidina a 2% como substância quimica auxiliar e medicados com pasta de hidroxido de calcio e clorexidina, a qual foi mantida nos canais por uma semana. Em uma segunda consulta, a porcao apical dos canais foi selada com barreira apical de MTA, com espessura de aproximadamente 3-4 mm. As demais porcoes dos canais foram obturadas com tecnica de plastificacao termomecânica da guta-percha, utilizando cimento a base de oxido de zinco e eugenol. Controle pos-operatorio de 6 meses e 1 ano mostraram resposta radiografica satisfatoria e ausencia de sintomas. CONCLUSAO: Atualmente, MTA apresenta-se como uma opcao interessante para casos de rizogenese incompleta e necrose pulpar, apresentando como vantagem o menor tempo de tratamento requerido.