ENAMEL WEAR CAUSED BY MONOLITHIC ZIRCONIA CROWNS FOLLOWING THREE MONTHS OF CLINICAL USE

G. Zenunaj¹ , E. Qorri² , D. Iannaci¹ , E. Pieslinger³ , B. Hassan¹

¹ Clinical Division of Prosthodontics, Medical University of Vienna, Vienna, Austria
² Dental School, Albanian University, Tirana, Albania
³ Head of the Clinical Division of Prosthodontics, Medical University of Vienna, Vienna, Austria

Correspondence to:

Annals of Stomatology 2025 January-April; 5(1): 48-55

Received: 27 February 2025 Accepted: 3 April 2025

Download PDF

Abstract

To compare the amount of tooth wear induced by monolithic zirconia crown restorations placed in the posterior region with natural tooth wear on the contralateral side. Twenty-five patients in need of single crown restoration were included in this study. Crown preparation was performed according to clinically indicated guidelines, and definitive crown impressions were obtained using PVS material. Gypsum master cast models were fabricated, and single crown dies were sectioned. Crowns were milled using a CAD-CAM procedure from monolithic zirconia blocks, Prettau Anterior Multistratum (ZirconZahn, South Tirol, Italy), by the ZirconZahn method. The crowns were cemented and adapted intraorally. An impression was obtained immediately following crown insertion of both dental arches. Following three months of functional loading, the patients were recalled to obtain a second impression using the same procedure. The cast models were then optically scanned using a lab scanner (ZirconZahn S600 Arti scanner), and the resulting 3D surfaces were exported in STL file format and imported into CloudCompare reverse engineering software for analysis. The zirconia crown antagonists, as well as the contralateral tooth antagonists for all 25 cases, were segmented, and tooth wear was assessed as the negative space (wear surface difference) between the two surfaces. The root mean square (RMS) surface difference in millimeters between the two impressions was quantified. The resulting tooth wear was quantified in an Excel sheet and saved for statistical analysis. All patients presented for recall with no dropouts. SPSS statistical analysis software was used for analysis. Mean tooth wear of the zirconia crown antagonist was (10µm±1.05µm) and in the contralateral was (8µm±1.4µm) following three months of functional loading, and the differences were statistically significant at P=0.48. No crowns were lost, chipped, or dislodged at the follow-up visit. Within the limitations and the short follow-up period of this study, it can be concluded that tooth wear induced by monolithic zirconia restoration did not differ from naturally induced wear on the contralateral side. Further research is needed to corroborate the findings of this investigation.

Keywords: dentistry, lab scanner, monolithic zirconia, three-dimensional models, tooth wear