Surface roughness and translucency of glazed versus polished cubic ultra-translucent multi-layered zirconia: An in-vitro study

Abstract

Statement of the problem: The final surface finish after sintering or after adjustment procedure of monolithic zirconia restorations is an important issue. Currently, there is lack of evidence based recommendations regarding the best surface finishing protocols for achieving optimal surface roughness and translucency of cubic multi layered ultra-translucent monolithic zirconia. Aim: The purpose of this in vitro study was to assess the effect of surface finish protocols (glazing versus polishing) on the surface roughness and translucency of cubic ultra-translucent multi-layered zirconia. Materials and Methods: CAD/CAM fabricated ultra-translucent multi-layer cubic zirconia cylinders were cut into disc-shaped samples and sintered to end up with (16) discs of uniform dimensions 11mm diameter and 0.6mm thickness. Disc samples were divided into two equal groups according to the surface finish protocols. Group G: glazing surface finish. Group P: polishing surface finish. Surface roughness (Ra) was assessed by a non-contact profilometer and translucent parameter (TP) was assessed by spectrophotometer. Results: Surface roughness of studied samples of group 1 recorded (0.253±0.0009 µm) and (0.251±0.0024 µm) before and after glazing respectively. While for group 2 revealed (0.2547±0.0002 µm) and (0.2545±0.001 µm) respectively. While for translucent parameter of group 1 revealed (16.0553±2.659) and (15.3714±9.773) before and after glazing respectively. While for group 2 revealed (16.0553±2.659) and (14.242±8.325) respectively. There was a significant difference between both groups showing that glazing gave a smoother surface and more translucency than a polishing surface finish protocol. Conclusions: Glazing of cubic ultra-translucent multi-layered zirconia is better than polished surface finishing protocol regarding surface roughness and translucency.