Does treatment‐induced surface roughness of 3 mol% yttria‐stabilized tetragonal zirconia polycrystals influence the wear of opposing restorative materials? An in vitro study

Purpose This study aimed to investigate whether different surface treatments applied to 3 mol% yttria‐stabilized tetragonal zirconia polycrystals (3Y‐TZP), with comparable mean roughness ( R a ) values, result in comparable values of additional surface roughness parameters, and to evaluate the influence of zirconia surface topography on vertical substance loss of two opposing restorative materials: polymethacrylate‐based resin (PR) and lithium disilicate ceramic (LD). Materials and Methods Ninety‐six zirconia discs were assigned to 12 groups ( n = 8) according to surface treatment using airborne‐particle abrasion, diamond burs, or silicon‐carbide‐coated abrasive papers applied before and/or after sintering, resulting in defined R a surface roughness ranges ( R a = 0.3–0.8 µm). Linear roughness parameters were verified by laser scanning microscopy. Ninety‐six conical antagonist specimens (PR or LD; n = 48) were prepared. The zirconia specimens (agonists) were subjected to mechanical loading for 1.2 million cycles, and vertical material loss was evaluated. Statistical analysis was performed using Kruskal–Wallis and Mann–Whitney tests followed by Bonferroni–Holm correction at a significance level of α = 0.05. Results Despite comparable R a values, different surface treatments resulted in significantly different roughness parameters ( R p , R z , R c , R t ; p ≤ 0.05), with airborne‐particle abrasion exhibiting the roughest surfaces. Agonist's roughness did not influence antagonist wear ( p = 0.739). However, the antagonist material LD, with median values up to 460 µm, showed a greater vertical material loss ( p = 0.019) compared to PR. Conclusions Within the range of surface treatments investigated, the R a of 3Y‐TZP might be sufficient to characterize surface topography with regard to wear behavior. LD, when opposed to 3Y‐TZP, may exhibit greater vertical material loss than PR.