Evaluation of resin composite materials. Part I: in vitro investigations

To evaluate different resin-based composites using a variety of in vitro investigation methods to predict their clinical behavior.

Materials selected for this study were Heliomolar radiopaque (microfilled), Tetric Ceram, Pertac II (minifilled hybrids), Ariston pHc (ion releasing hybrid), and Solitaire I (hybrid with porous fillers). The evaluated in vitro criteria were three-body wear according to the ACTA method, microtensile bond strengths to enamel and dentin, flexural strength (four-point bending strength), flexural fatigue behavior (flexural fatigue limit), and calcium ion release (for Ariston pHc).

Concerning wear resistance, Ariston pHc (20.5 microm after 200,000 cycles) was inferior to the other materials (13.7-15.9 microm). Microtensile bond strengths to dentin were similar for Heliomolar (32.0 MPa), Tetric Ceram (30.4 MPa; both bonded with Syntac Classic), and Pertac II (30.8 MPa; bonded with EBS Multi) being above Solitaire I (22.5 MPa; bonded with Solidbond) being above Ariston pHc (13.2 MPa; bonded with Ariston Liner). Enamel bond strengths for Heliomolar (40.0 MPa), Tetric Ceram (36.5 MPa), and Pertac II (38.9 MPa) were significantly higher than for Solitaire I (26.6 MPa) which was above Ariston pHc (7.2 MPa). Heliomolar, Tetric Ceram, and Pertac II revealed higher micro-TBS to enamel than to dentin, Ariston showed the contrary, and Solitare exhibited no difference between enamel and dentin micro-TBS. Solitaire I exhibited a lower initial flexural strength than the other materials, the computed fatigue strength of the material even dropped to the level of glass ionomer cements (17.9 MPa). Long-term calcium release data for Ariston exhibited a continuously high calcium release becoming lower at the end of the observation beyond 21 months.