Surface Roughness of Dental Porcelain Fused-To-Nickel Chromium Using Different Polishing Materials and Glazing Techniques

Background: Rough dental porcelain surface due to incorrect glazing technique or occlusal adjustment can cause wear of opposing teeth and tissue irritation. The aim of this study was to measure the surface roughness of low-fusing dental porcelain after treatment with different polishing materials and glazing techniques. Materials and Methods: Seventy metal-ceramic specimens were fabricated and divided into seven groups according to type of surface treatment. Group I: Unglazed porcelain (control group). Group II: Porcelain polished with sandblast powder and then autoglazed, Group III: Porcelain polished with sandblast powder and then applied glaze. Group IV: Porcelain polished with sandblast powder and then porcelain rubber wheels. Group V: Porcelain polished with sandblast powder, porcelain rubber wheel and then polishing paste. Group VI: Porcelain polished with sandblast powder, porcelain rubber wheels, polishing paste and then autoglazed Group VII: Porcelain polished with sandblast powder, porcelain rubber wheels, polishing paste and then applied glazed. The surface roughness averages “Ra” of the specimens have been determined using the profilometer. Results: One way – ANOVA showed highly significant differences among tested groups. Group I showed roughest group with highly significant differences among all tested groups. Followed by group II with highly significant differences, then group III which showed no significant differences with group VII, which is the smoothest group scored. Also group IV showed “Ra” values compared with group VI. While group V showed slightly significant differences with group VII (LSD test). Conclusion: Polished porcelain with (rubber wheel and polishing paste) can be considered a good alternative to applied glazed of porcelain restoration which is characterized by time consuming and sensitive technique. Moreover, autoglazing porcelain followed by polishing or without polishing , proved to be disadvantageous since it increases surface roughness