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 15min after curing for 20, 40 and 60s and after 1h, 24h, 7 d, and 30 d storage at 37°C in water. Volumetric changes (ΔV) 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

ΔV 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 ΔV≈+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.

Keywords: Dentistry, Resin-based filling material, Volumetric shrinkage, Water sorption, Physical properties