Effect of prophylaxis regimens on surface roughness of glass ionomer cements

This study investigated the surface roughness of conventional (Fuji II Capsulated [FC], GC Corporation, Tokyo, Japan), resin-modified (Fuji II LC [FL], GC Corporation) [FL] and highly viscous (Fuji IX GP Fast [FN], GC Corporation) glass ionomer cements [GICs] after exposure to five prophylaxis regimes. The surface roughness obtained was compared to untreated polished specimens (control). The prophylaxis regimes evaluated were rotating brush with pumice-water slurry [PB]; rotating rubber cup with pumice-water slurry [PC]; rotating rubber cup with prophylaxis paste [PP]; rotating rubber cup with prophylaxis gel [PG] and air-powder polishing [PJ]. Forty-eight specimens (3-mm long x 3-mm wide x 2-mm deep) were made for each material. The specimens were stored in distilled water at 37 degrees C for one month, polished with 1200 grit sandpaper using a lapping device and randomly divided into six groups (n=8). They were then stored for an additional two months in distilled water at 37 degrees C prior to exposure to the various prophylaxis regimens. The mean surface roughness value (Ra; microm) was measured with a profilometer. Data was subjected to ANOVA/Scheffe's tests at significance level 0.05. Mean Ra ranged from 0.30 to 1.70 microm for FC, 0.40 to 2.52 microm for FL and 0.36 to 1.79 microm for FN. Regardless of the type of glass ionomer, treatment with PJ resulted in significantly rougher surfaces when compared to the control group. For FC and FN, a significant increase in roughness was observed after treatment with PB and PP, respectively. Glass ionomer restorations may require re-polishing after exposure to some prophylaxis regimens.