Polymerization shrinkage and hygroscopic expansion of contemporary posterior resin-based filling materials—A comparative study

Abstract

Objectives To investigate the polymerization shrinkage and hygroscopic expansion of contemporary posterior resin-based filling materials. Methods The densities of SureFil (SU), CeramXMono (CM), Clearfil AP-X (CF), Solitaire 2 (SO), TetricEvoCeram (TE), and Filtek P60 (FT) were measured using the Archimedes’ principle prior to and 15 min after curing for 20, 40 and 60 s and after 1 h, 24 h, 7 d, and 30 d storage at 37 °C in water. Volumetric changes (Δ V) in percent after polymerization and after each storage period in water were calculated from the changes of densities. Water sorption and solubility were determined after 30 d for all specimens and their curing times. Two-way ANOVA was calculated for shrinkage and repeated measures ANOVA was calculated for hygroscopic expansion ( p < 0.05). Results Δ V depended on filler load but not on curing time (SU ≈ −2.0%, CM ≈ −2.6%, CF ≈ −2.1%, SO ≈ −3.3%, TE ≈ −1.7%, FT ≈ −1.8%). Hygroscopic expansion depended on water sorption and solubility. Except for SU, all materials showed Δ V ≈ +1% after water storage. Conclusion Polymerization shrinkage depended on the type of resin-based filling material but not on curing time. Shrinkage was not compensated by hygroscopic expansion.