Abstract
The purpose of this study was to investigate the effect of different post space preparation techniques and times on the apical seal of two types of gutta-percha obturation techniques. Materials and methods: Two hundred extracted human lower premolars were selected for this study. All teeth were decoronated to adjust the working length at 14 mm. The canals were instrumented with ProTaper rotary instruments to size F3. The (200) root canals were randomly divided into two groups (100) of each according to the obturating method. Then each group was sub divided into (10) sub groups (10) of each (2 control groups and 8 experimental groups). Nine mm segment of gutta-percha was removed from the roots in each of the experimental groups either immediately after obturation or 7 days later using either heated pluggers, or Gates-Glidden drills or ProTaper rotary instruments or peeso reamers. The roots in the control groups were left without any post space preparation. The canal orifice of the roots in the experimental groups was sealed with amalgam. The extend of linear dye leakage was measured in mm with a stereomicroscope at (X 20). One-way ANOVA and sheffe statistical analysis were performed to the data collected. Results: The groups with ProTaper rotary instrument prepared the post space immediately after obturation( gps 3,11), showed the lowest mean leakage, but the difference was not statistically significant than the other experimental groups. T-test represented no significant differences existed at either two time interval studied and the type of obturation techniques. Sheffe-test for the post space preparation techniques revealed that there were a significant differences occurred with the use of ProTaper rotary instruments regardless the time interval and the obturation techniques. Conclusions: ProTaper rotary instrument provided less microleakage comparing to the other instruments used to prepare the post space. The post space preparation did not affect the apical seal in comparison with that of the intact filling.
