IN-VITRO AGING OF A HEAT PRESSURE-CURED COMPOSITE

Specimens of a heat/pressure-cured microfill composite were aged in sa line or distilled water at 37-degrees-C up to 12 mon to determine if t he flexure strength was affected by the aging media. No significant di fference in the flexure strength was observed between the controls and the 12 mon aged specimens. Cyclic testing in distilled water resulted in a lower flexure strength at fracture than that observed for the ag ed specimens. This lower strength is attributed to fatigue of the sila ne bond, the resin matrix, and/or the filler particles.