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Background. The aim of this study was to evaluate the effect of acidic, neutral and alkaline environments on the solubility of white mineral trioxide aggregate (WMTA) and Biodentine (BD). Methods. Thirty-nine ring molds were randomly divided into three groups of A, B, and C (n = 12) with pH values of 7.4, 4.4 and 10.4, respectively, and an empty mold was used as a control. Each group was further divided into two subgroups (1 and 2) according to the material studied. The samples in groups A, B and C were transferred into synthetic tissue fluid buffered at pH values of 7.4, 4.4 and 10.4, respectively, and kept in an incubator at 37°C with 100% humidity. Daily solubility at 1-, 2-, 5-, 14-, 21-, and 30-day intervals and cumulative solubility up to 5-, 14-, and 30-day intervals were calculated. Statistical analysis was carried out with independent-samples t-test, two-way ANOVA and post hoc Tukey tests using SPSS 18. Statistical significance was set at P<0.05. Results. Both WMTA and BD exhibited the highest solubility in acidic pH with 5.4235±0.1834 and 10.7516±0.0639 mean cumulative solubility values at 30-day interval, respectively. At all exposure times, BD was significantly more soluble than WMTA (P<0.001). Conclusion. Acidic periapical environment jeopardized the solubility of both WMTA and BD, affecting their sealing characteristics in clinical applications like perforation repair procedures and blunderbuss canals.

Introduction:In cases of severe hard tissue loss, 2 mm circumferential ferrule is difficult to achieve which leads to incorporation of different ferrule designs.Aim:To compare and evaluate the effect of different crown ferrule designs on the fracture resistance of mandibular premolars restored with fiber posts, composite cores, and crowns.Materials and Methods:Fifty freshly extracted mandibular premolars were endodontically treated and divided into five groups: Group I - 2 mm circumferential ferrule above the cementoenamel junction (CEJ); Group II - 2 mm ferrule on the facial aspect above CEJ; Group III - 2 mm ferrule on the lingual aspect above CEJ; Group IV - 2 mm ferrule on the facial and lingual aspects above CEJ with interproximal concavities, and Group V - no ferrule (control group) and were later restored with fiber posts, composite cores, and crowns. Specimens were mounted on a universal testing machine, and compressive load was applied at a crosshead speed of 1 mm/min until fracture occurred.Results:The results showed that circumferential ferrule produced the highest mean fracture resistance and the least fracture resistance was found in the control group.Conclusion:Circumferential ferrule increases the fracture resistance of endodontically treated teeth restored with bonded post, core, and crown.

Background. Maximum sealing ability or adhesion of endodontic sealers can be achieved after effective removal of the smear layer. Endodontic irrigants assist in adequate removal of the smear layer, improving the retention mechanism. The aim of this study was to evaluate the effect of two different root canal irrigation solutions (5.25% NaOCl followed by 17% EDTA and QMix) on the apical sealing ability of two different root canal sealers (MTA Fillapex and Adseal).Methods. Forty-six single-canal teeth were divided into 4 experimental groups of 10 teeth each and a positive and negative group of 3 teeth each. The root canals were prepared using step-back technique. The teeth in groups 1 and 2 were irrigated with 5.25% NaOCl followed by 17% EDTA and the teeth in groups 3 and 4 were irrigated with QMix. Finally all the teeth were flushed with sterile saline and dried using paper points. Obturation was accomplished by gutta-percha using lateral condensation technique. MTA Fillapex sealer was used in groups 1 and 3 whereas Adseal was used in groups 2 and 4. Dye penetration method was used to evaluate apical leakage. Data were analyzed with Kruskal-Wallis and Mann-Whitney U tests using SPSS 14. Statistical significance was set at P < 0.05.Results. Group 3 showed maximum amount of apical leakage (3.7±0.3 mm) whereas group 2 exhibited the least amount of apical leakage (2.1 ± 0.4 mm) among all the experimental groups. Significant differences were found in the amount of apical leakage between all the groups (P = 0.00001).Conclusion. Within the limitations of this study, 5.25% sodium hypochlorite followed by 17% EDTA and Adseal resulted in the best apical seal.

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