Micro-computed tomographic evaluation of the apical seal of endodontically treated teeth by two obturating techniques and two post space preparation techniques

Aim: This study evaluated apical seal of teeth obturated by two techniques and gutta-percha (GP) removed by two methods for post space preparation, using micro-computed tomography (micro-CT). Materials and Methods: Fifty-six single rooted teeth were decapitated at 15mm from the apex and prepared using ProTaper Universal System. Specimens were divided into two main groups of 28 each according to technique of GP Removal and post space preparation: Group A1, GP removed by a penetrating drill and Group A2, GP removed by hot plugger. Each main group was divided into two subgroups according to obturation technique: single cone (SC) and System B. Each subgroup was further divided into two minor subgroups according to storage time-immediately and one-week post-obturation. Approximately 9mm of GP was removed for post space preparation. All specimens were scanned three times by micro-CT: post-preparation, post-obturation, and after post space preparation. Total mean percentage of voids/gaps in the apical portion was calculated at 1, 3, and 5mm from the apex. Data were explored for normality using Kolmogorov-Smirnov and Shapiro-Wilk tests. Paired sample t-test was used to compare between two groups. Independent sample t-test was used to compare between two groups in non-related samples (significant P <= 0.05). Results: It showed that group A2 recorded significantly lower voids than group A1 at the two investigation periods. Voids associated with System B technique were lower than those with SC. Conclusion: An immediate removal of GP by hot plugger would not affect the apical seal.