Effect of hygiene maintenance procedures on surface roughness of composite restoratives

This study investigated the effect of various hygiene maintenance procedures on the surface finish of minifill (Filtek A110 [AO], 3M-ESPE), flowable (Filtek Flow [FF], 3M-ESPE) and poly-acid-modified (F2000 [FT], 3M-ESPE) composites. Procedures included pumice-water slurry with rotating brush (PB), pumice-water slurry with rotating rubber cup (PC), prophylaxis paste with rubber cup (ZC), prophylaxis gel with rubber cup (GC) and air-powder polishing (AP). Specimens not exposed to these procedures were used as the control group. For each material, 48 specimens (3-mm long x 3-mm wide x 2-mm deep) were made and stored in distilled water at 37 degrees C for one month. The specimens were then treated with 1200 grit sandpaper using a lapping device, stored for an additional two months in distilled water at 37 degrees C and randomly divided into six groups (n=8). The mean surface roughness (Ra, microm) of the specimens after exposure to the various hygiene procedures was determined using a surface profilometer. Data was subjected to ANOVA/Scheffe's test at significance level 0.05. Mean Ra values ranged from 0.09 to 2.17, 0.06 to 1.38 and 0.38 to 1.25 for AO, FF and FT, respectively. The effect of hygiene procedures on surface roughness was material dependent. Among the various procedures, the smoothest surface was observed after treatment with prophylaxis gel and the roughest with air-powder polishing. For all materials, the use of pumice-water slurry with brush also caused significant roughening. Composite restorations may require re-polishing after exposure to some hygiene maintenance procedures, as Ra values exceeded the critical threshold surface roughness for bacterial adhesion (0.2 microm).