Degradation resistance of ormocer- and dimethacrylate-based matrices with different filler contents

To investigate the influence of matrix and filler content on degradation resistance of an experimental pure-ormocer and an dimethacrylate-based composite derived from a commercially available material.

A dimethacrylate- Grandio (GR) and a model pure ormocer-based-matrix ORMOCER (ORM) were used. Each material had three different types according to their filler content (% w/w): regular (87% and 86%), flowable (80% and 79%) and fissure sealer (70% and 69%) for GR and ORM respectively. Disc-shaped (1 mm thickness×10 mm diameter) samples were prepared for each material (n=6). Water sorption and solubility tests were adapted from ISO4049. To evaluate porosity, specimens were scanned at a resolution of 19.4 μm and 3D reconstructions were made. The volume ratio of pores in the specimens were calculated and expressed as percentages. The results were submitted to 2-way ANOVA (factors: matrix and filler content) and Tukey post-hoc statistic test (p=0.05).

Filler content influenced the water sorption for the ormocer-matrix and the water solubility for the dimethacrylates. ORMOCER regular was a less porous material compared to flowable and sealer formulations. On the other hand, the filler content had no effect on porosity for Grandio.

Modifications made in the pure ormocer-matrix formulation were not significantly important to produce a more water-stable material compared to the dimethacrylate-matrix composite materials.