The Influence of Thermomechanical Compaction on the Marginal Adaptation of 4 Different Hydraulic Sealers: A Comparative Ex Vivo Study

Since there are no data in the literature regarding the comparison of the marginal adaptation of hydraulic sealers when used with a single-cone technique or through thermomechanical compaction, this study aimed to evaluate the behavior of four different endodontic sealers used with the two above-mentioned obturation techniques by evaluating the marginal gap existing between the obturation materials and the dentinal walls through scanning electron microscopy. Given this objective, a total of 104 single-rooted, straight canal teeth were selected and divided into four subgroups according to the selected endodontic sealer ((AH) Plus Bioceramic Sealer (AHP), EndoSequence BC Sealer HiFlow (ES), C-Root SP (CR), and GuttaFlow Bioseal (GF)). Each tooth was decoronated and instrumented with the HyFlex EDM/CM systematics up to 30.04. After irrigation procedures, the teeth of each subgroup were divided into two groups and obturated according to two different obturation techniques: the single-cone technique (SC) and the thermomechanical compaction technique (TC). After the required sealer setting time, each tooth was sectioned in three parts at 3, 6, and 9 mm from the apex, and each section was observed with a scanning electron microscope. The marginal gap of each sample was measured using G* Power Software v3.1, and the statistical analysis was performed using the Kruskal-Wallis test, followed by a post hoc Dunn's test. Results showed that there were not any statistically significant differences in terms of the marginal gap between the two different above-mentioned obturation techniques for each sealer, except for the middle third of root canals, where a statistically significant difference was found for AHP, ES, and GF sealers. In conclusion, the thermomechanical compaction of hydraulic sealers and gutta-percha guarantees better sealing than the single-cone technique when the root canal shape is not rounded.

Automated summary

This study evaluated the marginal gap between obturation materials and dentinal walls using scanning electron microscopy for four different endodontic sealers with the single-cone technique or thermomechanical compaction. The results showed no significant differences in marginal gap between the two obturation techniques for each sealer, except for the middle third of root canals for AHP, ES, and GF sealers. In conclusion, the thermomechanical compaction technique combined with hydraulic sealers and gutta-percha provides better sealing than the single-cone technique when the root canal shape is not rounded.