Evaluation of the effects of clinical adaptationprocedures of two translucent, monolithic zirconium restoration manufacturedwith the use of CAD/CAM systems on the optical and mechanical properties of thematerial

Objective: In this in vitro study, it was aimed to examine the effect of surface treatments applied to monolithic zirconium restorations on the translucency, surface roughness, surface topography and bending strength of the material. Materials and methods: In accordance with ISO 6872, a total of 126 samples of 15mm in diameter and 1.2mm (group to be grinded- 1.3mm) in thickness, were prepared in disc form from monolithic zirconium with two different yttrium ratios using Computer-aided design (CAD) and Computer-aided manufacturing (CAM). The samples obtained from STML and UTML blocks were randomly divided into three groups (sintered, etched, etched-polished) and surface treatments were applied. The samples were aged in an autoclave at 134°C, under 2 bar pressure, for 1 hour, then translucency parameters, surface roughness values were determined, scanning electron microscope (SEM) images were taken and biaxial flexural strength test was performed on three balls. Data were evaluated with Kruskal Wallis test and Mann Whitney U test with Benjamini-Hochberg correction. Results: Comparing the subgroups for each of the STML and UTML groups, it was determined that the sintered subgroup had statistically significantly higher flexural strength than the grinding and grinding-polishing subgroups. In both the STML and UTML groups, griding increased the surface roughness, while polishing significantly decreased the surface roughness. In terms of other measures, no statistically significant difference was found between the STML and UTML groups. Conclusion: It was determined that the clinical adaptation procedures affected the surface roughness and bending strength of monolithic zirconium and did not affect. the translucency parameter. Keywords: monolithic zirconium, clinical adjustment, surface roughness, flexural strength.