This study compared the effect of an activator, intermediate bonding resin and low-viscosity flowable resin on the microtensile bond strength of a self-curing composite resin used with two-step total etching adhesives. Twenty extracted permanent molars were used. The teeth were assigned randomly to nine groups (n=10) according to the adhesive system and application of additional methods (activator, intermediate adhesive, flowable resin). The bonding agents and additional applications of each group were applied to the dentin surfaces. Self-curing composite resin buildups were made for each tooth to form a core, 5mm in height. The restored teeth were then stored in distilled water at room temperature for 24h before sectioning. The microtensile bond strength of all specimens was examined. The data was analyzed statistically by one-way ANOVA and a Scheffe's test. The application of an intermediate bonding resin (Optibond FL adhesive) and low-viscosity flowable resin (Tetric N-flow) produced higher bond strength than that with the activator in all groups. Regardless of the method selected, Optibond solo plus produced the lowest µTBS to dentin. The failure modes of the tested dentin bonding agents were mostly adhesive failure but there were some cases showed cohesive failure in the resin.

The purposes of this study were to compare the efficacy of irrigation systems by removing a calcium hydroxide (Ca(OH)₂) paste from the apical third of the root canal and the effect of the patency file. Sixty single rooted human teeth were used in this study. The canals were instrumented by a crown-down manner with .04 taper ProFile to ISO #35. Ca(OH)2 and distilled water were mixed and placed inside the root canals. The teeth were divided into 6 groups according to the root canal irrigation system and the use of patency file as follows: group 1 - conventional method; group 2 - EndoActivator^®; group 3 - EndoVac^®; group 4 - conventional method, patency; group 4 - EndoActivator^®, patency; group 6 - EndoVac^®, patency. All teeth were irrigated with sodium hypochlorite. After the root canal irrigation, the teeth were split in bucco-lingual aspect. Percentage of the root canal surface coverage with residual Ca(OH)2 until 3 mm from working length was analyzed using Image Pro Plus ver. 4.0. Statistical analysis was performed using the One-way ANOVA, t-test and Scheffe's post-hoc test. Conventional groups had significantly more Ca(OH)2 debris than EndoActivator^®, EndoVac^® groups. There was no significant difference between EndoActivator^® and EndoVac^® groups. Groups with patency file showed more effective in removing Ca(OH)₂ paste than no patency groups, but, it was no significant difference. This study showed that EndoActivator^® and EndoVac^® systems were more effective in removing Ca(OH)2 paste from the apical third of the root canal than conventional method.

The aim of this study was to evaluate endodontic irrigation methods with EndoVac^® and EndoActivator^® in the elimination of Enterococcus faecalis from the root canals. Extracted 70 human single-rooted teeth were used. The canals were instrumented by a crown-down technique with .04 taper ProFile to ISO size 40. After the teeth were autoclaved, the canals were inoculated with E. faecalis and incubated for 48 h. The teeth were randomly divided into three experimental groups of 20 teeth each according to canal irrigation methods and two control groups as follows: group 1 - EndoVac^®; group 2 - EndoActivator^®; group 3 - Conventional needle irrigation method. After canal irrigation using 2.5% NaOCl, first samples (S1) were taken using sterile paper point. And the canals were filled with sterile brain heart infusion (BHI) broth and incubated for 24 h, then second samples (S2) were taken. The samples were cultured on BHI agar plate to determine the numbers of colony forming units (CFU). In first sampling (S1), only one canal of conventional method among the all experimental groups was positive cultured. In second sampling (S2), EndoVac^® group showed the least positive culture numbers of E. faecalis. There was statistically significant difference between the EndoVac^® and conventional needle irrigation methods in the mean value of Log CFU. According to the results of this study, EndoVac^® showed better efficacy than conventional needle irrigation method in the elimination of E. faecalis from the root canal.