Effect of incorporating long polyethylene fibers in resin composite on polymerization shrinkage strain and degree of monomer conversion (An In-vitro Study)
摘要
Polymerization shrinkage remains a significant drawback of resin composites, potentially leading to deformation of the restoration. Recent advances in biomimetic dentistry have produced dentin-like materials. This study will evaluate polymerization shrinkage strain (PSS) and degree of conversion (DC) of a biomimetic approach using long polyethylene fiber to two short-fiber-reinforced resin composites (SFRCs).
MethodsPolyethylene long-fiber-reinforced nanohybrid resin composite (Tetric N Ceram) and short-fiber-reinforced composites (EverX Posterior [EXP] and EverX Flow [EXF]) were prepared and divided into four groups (n = 20/group). The test divided each group into two subgroups (10 specimens per test). Polymerization shrinkage strain (PSS) was measured pre- and post-gel during the 20-second curing of the resin composite. DC was measured using Fourier transform infrared spectroscopy (FTIR). Data was analyzed using a one-way ANOVA and Tukey’s post hoc test. Statistical significance was set at p < 0.05 for all analyses.
ResultsThe post-gel shrinkage strain difference between polyethylene fiber-reinforced Nanohybrid resin composite (TNCF) and SFRC (EXP) was not statistically significant. The EXF exhibited significantly higher shrinkage strain pre- and post-gel compared to other materials (p < 0.001). Nevertheless, EXF achieved the highest DC (73.14%), with no significant differences between EXF and TNCF or between EXP and TNCF.
ConclusionsCombining conventional resin composite (Tetric N Ceram) with long polyethylene fibers results in a polymerization shrinkage strain comparable to that of a short-fiber-reinforced bulk-fill composite (EverX Posterior). Additionally, neither short nor long fibers compromises the degree of monomer conversion, which remains within clinically acceptable limits and shows no direct correlation with post-gel shrinkage strain.
Clinical significanceResearchers seek restorative materials with minimal polymerization shrinkage to reduce marginal leakage and postoperative sensitivity, and high monomer conversion to enhance strength and biocompatibility. Resin composites with polyethylene fibers and EverX Posterior seem promising.