Comparative wear resistance of reinforced glass ionomer restorative materials

This study investigated the wear resistance of three restorative reinforced glass ionomer cements (Fuji IX GP FAST [FJ], Miracle Mix [MM] and Ketac Si lver [KS]). Microfilled (Silux [SX]) and mini-filled (Z100 [ZO]) composites were used for comparison. Six specimens were made for each material. The s pecimens were conditioned for one week in distilled water at 37 degreesC an d subjected to wear testing at 20 MPa contact stress against SS304 counterb odies using a reciprocal compression-sliding wear instrumentation. Distille d water was used as lubricant. Wear depth (mum) was measured using profilom etry every 2,000 cycles up to 10,000 cycles. Results were analyzed using AN OVA/Scheffe's test (p<0.05). After 10,000 cycles of wear testing, ranking w as as follows: KS>ZO>MM>FJ>SX. Wear ranged from 26.1 mum for SX to 71.5 mum for KS. The wear resistance of KS was significantly lower than FJ, MM and SX at all wear intervals. Although KS had significantly more wear than ZO a t 2,000 to 6,000 cycles, no significant difference in wear was observed bet ween these two materials at 8,000 and 10,000 cycles. Sintering of silver pa rticles to glass ionomer cement (KS) did not appear to improve wear resista nce. The simple addition of amalgam alloy to glass ionomer may improve wear resistance but results in poor aesthetics (silver-black color). FJ, which relies on improved chemistry instead of metal fillers, showed comparable we ar resistance to the composites evaluated and is tooth-colored. It may serv e as a potential substitute for composites in low-stress situations where f luoride release is desirable and aesthetic requirements are not high.