Ultrasonic activation of calcium silicate sealers in single-cone obturation: A micro-CT study of voids and gaps formation.

Abstract

This study investigated the effect of ultrasonic activation (UA) on porosity formation in root fillings using two calcium silicate-based sealers. Forty single-rooted premolars were decoronated, and the roots were adjusted to a standardized length of 11 mm. Canals were shaped with the #F3 ProTaper Ultimate file system. Teeth were divided into two groups for single-cone obturation with two different sealers: Angelus Bio-C Sealer (n = 20) and TotalFill BC Sealer (n = 20). Each group was subdivided into two subgroups (with and without UA). In the UA groups, the tweezers holding the GP cone were contacted by a smooth ultrasonic tip for two to three seconds. After obturation, samples were scanned using micro-CT. Group differences in mean total porosity were analyzed with Mann-Whitney Z and Kruskal-Wallis tests, followed by Dunn-Bonferroni post-hoc tests. Interfacial gaps and internal voids were also quantified separately to assess distribution. TotalFill BC Sealer with ultrasonic activation demonstrated the highest mean total porosity, whereas Angelus Bio-C Sealer without ultrasonic activation exhibited the lowest, though this difference was not statistically significant (p  =  0.428). Quantitative analysis revealed that interfacial gaps were significantly higher than internal voids across all groups (p < 0.05). Total porosity varied significantly across root levels (p < 0.001), with the cervical third showing the greatest proportion of porosities, followed by the apical third, while the middle third consistently demonstrated the lowest porosity volume. No significant difference in total porosity was found between Bio-C Sealer and TotalFill BC Sealer, regardless of ultrasonic activation. However, interfacial gaps represented the majority of the total porosity volume, and significant differences in distribution were observed across different root levels.