Volumetric Alterations and Bond Performance of Epoxy Resin, Silicone Bioactive Glass, and Bioceramic Sealers...

The aim of this study is to evaluate the time-dependent volumetric changes, push-out bond strength (POBS), and dentine adaptation of epoxy resin, silicone bioactive glass and calcium silicate root canal sealers over 60 days.

One hundred and twenty-five mandibular premolars were instrumented using ProTaper Next (size 40/06) and assigned to five groups (n = 25). Each canal was obturated using the matched single-cone technique with one of the following sealers: AH Plus Jet (AHP Jet), GuttaFlow Bioseal (GFB), CeraSeal (CS), Endosequence BC (ES BC), or AH Plus Bioceramic (AHP Bioceramic). In each group, 20 samples were subdivided into two subgroups (n = 10) to assess POBS (push-out test) and dentine adaptation (scanning electron microscopy) of the filling materials at 2 and 60 days post-obturation. Micro-computed tomography (Micro-CT) was used to evaluate sealer volumetric changes over 60 days (n = 5).

Two-way ANOVA assessed the interaction between sealer type and post-obturation time on POBS. One-way ANOVA compared POBS and volumetric alterations among the sealers, while paired and independent t-tests evaluated differences within each sealer. Kruskal-Wallis and Mann-Whitney U tests were used to analyze interfacial adaptation.

For the POBS, AHP Jet, CS, and ES BC exhibited higher POBS values than GFB and AHP Bioceramic at 2 days post-obturation (p < 0.001). At the 60-day evaluation, CS and ES BC demonstrated higher POBS than the other sealers (p < 0.001), whereas GFB exhibited the lowest value. No significant difference in dentine adaptation was found among the sealers at either 2 days (p = 0.07) or 60 days (p = 0.08). After 60 days post-obturation, GFB, CS, ES BC, and AHP Bioceramic showed a significantly higher POBS (p < 0.001) and dentine adaptation (p < 0.05) than under the 2-day condition, whereas AHP Jet maintained consistent POBS (p = 0.87) and dentine adaptation (p = 0.76). Micro-CT revealed that silicone bioactive glass and bioceramic sealers expanded, whereas the epoxy resin sealer showed slight shrinkage after setting.

CS and ES BC demonstrated the most stable long-term POBS, whereas all sealers illustrated favorable dentine adaptation. The volumetric expansion might relate to improvements in bond strength and dentine adaptation post-obturation in silicone bioactive glass and bioceramic sealers.