Influence of endodontic access cavity design on the effectiveness of different retreatment protocols in mandibular molars obturated with bioceramic or epoxy resin-based sealer: a micro-CT analysis
Authors
Laila Gonzales Freire, Manuela Gimenes Lupi, Carla Regina do Carmo Della Libera, Samara Daher Teixeira Castro, Giulio GaviniFiles
Key Information
Journal
Published in Vol. 6 No. 1 (2026) of Brazilian Endodontic Journal.
About the JournalAbstract
Aim: To evaluate the influence of endodontic access cavity design on the volumetric percentage of remaining filling material after different retreatment protocols in mandibular molars, assessed using micro-computed tomography (micro-CT).
Methodology: Sixty-four mandibular molars previously prepared and obturated with either AH Plus (epoxy resin-based) or Bio-C Sealer (bioceramic) were distributed according to access cavity type: traditional (TAC, n=32) or conservative (CAC, n=32), and further subdivided by sealer and complementary retreatment protocol: ProTaper Retreatment + XP-Endo Finisher R (XPFR) or ProTaper Retreatment + Clearsonic Black ultrasonic insert (CLEAR). Micro-CT scans (SkyScan 1276) were performed after obturation, initial filling removal, and complementary filling removal. The volumetric percentages of the remaining filling material were calculated for each root (mesial/distal) and root third (cervical/middle/apical). Three-way ANOVA and Tukey's tests were performed (α = 0.05).
Results: TAC exhibited significantly higher initial filling material removal compared to CAC in the cervical and middle thirds of both mesial and distal roots (p < 0.05). AH Plus demonstrated greater retreatability than Bio-C Sealer in all groups (p < 0.05). The Clearsonic insert outperformed XPFR overall, especially in the distal canals (p < 0.05). The apical third showed the lowest removal efficiency, regardless of the protocol.
Conclusions: Initial retreatment efficiency was enhanced through traditional access. AH Plus demonstrated greater retreatability compared to Bio-C Sealer. The Clearsonic insert was particularly effective in removing filling material, especially from the distal canals. No protocol succeeded in achieving complete filling removal.
References
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Copyright (c) 2026 Laila Gonzales Freire, Manuela Gimenes Lupi, Carla Regina do Carmo Della Libera, Samara Daher Teixeira Castro, Giulio Gavini
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