Surface Roughness of Lithia-disilicate-based Crowns after Two Year of Insertion

OBJECTIVES: The objective of this study was to evaluate the surface roughness of veneered lithia-disilicate-based posterior crowns after two year of insertion.

METHODS: Twenty posterior crowns were made using the heat-pressing technique and lithia-disilicate-based core ceramic. After try-in and occlusal adjustment, each crown was glazed before insertion. Patients were recalled after cementation for one year and two year. The quality of crowns and adjacent gingival tissues were examined and impressions were taken for replica models at baseline and each appointment. Surface roughness of replica models taken from ceramic crowns was measured using a profilometer. Statistical analyses of surface roughness values were performed using repeated measures ANOVA, and Tukey's multiple comparison test. RESULTS: The means surface roughness were 1.47 ± 0.32 ìm for baseline models, 2.1 ± 0.41 ìm for one-year recall, and 2.28 ± 0.43 ìm for two-year recall. The means surface roughness of replica models from two-year and one-year recalls were significantly higher than that of the baseline models. (p<0.05) CONCLUSION: The result from this study suggested a surface degradation of ceramic crowns over time. Increase surface roughness indicated the increase in surface irregularity that resulted from wear of ceramic surface.