The effect of different finishing & polishing protocols on the surface roughness & flexural strength of zirconia bars

Abstract

IntroductionThe aim of this study is to evaluate the effect of three different finishing and polishing protocols on the surface roughness and flexural strength of tetragonal zirconia. Materials and methods1: Surface roughness; One hundred and five bars of Y-TZP were prepared from Zenostar zirconia blocks (Ivoclar Vivadent). Fifteen bars were distributed into one of seven groups (n = 15/group). Three rotary systems were assessed for finishing and polishing zirconia. After surface preparation the surface roughness was measured using a non-contact profilometer (NPFlex Light interferometer, Bruker Corp., Tucson, AZ). 2: Flexural Strength; Flexural strength of the bars was determined using a three point bending test in a Universal Testing Machine (Instron). Results1: Surface roughness; A significant interaction was demonstrated between grinding condition and polishing kit (P = 0.001). 2: Flexural Strength; a statistically significant difference in flexural strength between groups was seen (p < 0.05). There was no significant interaction effect (P = 0.869). ConclusionsSurface adjustment with dry grinding conditions increased the surface roughness of Y-TZP using the Komet polishing kit compared to wet conditions. Dry grinding lowered the flexural strength compared to wet grinding, irrespective of the kit being used. Achieving a polished surface comparable to that of the control group can be possible by using Brasseler’s zirconia polishing kit under wet grinding conditions.