SURFACE-ROUGHNESS OF DENTIN AFTER TOOTH PREPARATION WITH DIFFERENT ROTARY INSTRUMENTATION

Although surface finish can be a critical variable in clinical perform ance, there is a dearth of information regarding surface characteristi cs of teeth prepared for artificial crowns, This study characterized t eeth prepared for complete cast restorations using three representativ e types of rotary instruments. One hundred and five standardized tooth preparations for complete crowns were performed using a modified mill ing machine on extracted human teeth with diamond, tungsten carbide, a nd tungsten carbide finishing burs of similar shape (n=35). The prepar ed dentin was analyzed with a surface profilometer and a scanning elec tron microscope (SEM). Differences between rotary instrument groups we re determined with parametric ANOVA and Tukey's Studentized Range (HSD ), Statistically significant differences in the surface topography of prepared teeth were seen, Mean surface roughnesses (Ra) were 8.6 and 6 .8 mu m for teeth prepared with diamond and tungsten carbide burs, Tee th completed with finishing burs appeared to result in a smoother surf ace (1.2 mu m).