Time-Dependent Volumetric and Porosity Changes of Bioceramic, Silicone Bioactive Glass-Based, and Epoxy Resin-Based Root Canal Sealers: A Micro-CT Analysis

To evaluate and compare volumetric changes in sealers and porosity of root canals filled with bioceramic, silicone bioactive glass-based, and epoxy resin-based sealers over 60 days.Eighty extracted mandibular premolars were instrumented with ProTaper Next files (size 40/06) and randomly assigned to five groups (<i>n</i> = 16), each canal filled with one of the following sealers: AH Plus Jet (AHP Jet), GuttaFlow Bioseal (GFB), CeraSeal (CS), EndoSequence BC (ES BC), and AH Plus Bioceramic (AHP Bioceramic). All canals were obturated using the matched single-cone technique. The change in sealer volume and porosity was assessed by micro-CT (<i>n</i> = 10/group) at 2, 30, and 60 days post-obturation. Scanning electron microscopy (SEM) evaluated interfacial adaptation at each time point (<i>n</i> = 2/group/time).Sealer volumetric changes, open, and total pores were normally distributed (Shapiro-Wilk test, <i>p</i> > 0.05). Two-way repeated measures ANOVA evaluated the interaction between sealer type and post-obturation time on sealer volumetric change and porosity. One-way ANOVA compared differences among sealers at each time point. Changes within each sealer over time were assessed using paired <i>t</i>-tests for two time points or repeated measures ANOVA with Bonferroni post hoc tests for comparisons involving three time points. Kruskal-Wallis and Friedman tests analyzed the closed pores.After setting, AHP Jet exhibited volumetric shrinkage, whereas bioceramic and silicone bioactive glass-based sealers showed volumetric expansion; however, statistically significant volumetric changes beyond 30 days were observed only for GFB (<i>p</i> = 0.011). Regarding porosity, bioceramic and bioactive glass-based sealers demonstrated significant reductions from 2 to 30 days (<i>p</i> < 0.05), with reductions observed across all time points in GFB (<i>p</i> < 0.05), whereas AHP Jet showed a significant increase over time (<i>p</i> < 0.05). SEM showed good sealer-dentine adaptation, and a more homogeneous interface was found in GFB and bioceramic sealers over time.Within the limitations of this study, bioceramic and silicone bioactive glass-based sealers showed volumetric expansion and reduced porosity after obturation, whereas the epoxy resin-based sealer exhibited volumetric shrinkage with increased porosity.