Controlled, prospective clinical split-mouth study of cast gold vs. ceramic partial crowns: 5.5 year results

To investigate the long-term clinical performance of cast gold partial crowns (CGPCs) as compared to partial ceramic crowns (PCCs). The null hypothesis tested was that CGPCs and PCCs would show similar clinical outcomes. In the present evaluation, the 5.5 year results are reported.

This was a controlled, prospective, clinical split-mouth study. In each patient, one CGPC (Degulor C) and one PCC (Vita Mark II ceramic/Cerec 3) had been inserted at baseline. After 5.5 years, 22 CGPC and 22 PCC restorations in 22 subjects attending the recall visit were clinically assessed using modified United States Public Health Service (USPHS) criteria. Kaplan-Meier survival rates were calculated for CGPCs and PCCs of the 29 subjects who had been originally enrolled in the study.

22 subjects (8 male, 14 female) participated in the 5.5-year recall with a total of 44 restorations. 22 CGPCs and 11 PCCs were placed in molars; 11 PCCs were placed in premolars. The median patient age was 37 years (32-44 years). All subjects revealed a papilla bleeding index (PBI) of < 20% (median: 7%). After 5.5 years, PCCs revealed a statistically significant, time dependant decrease of Alfa ratings for criteria anatomic form, marginal adaptation and marginal discoloration. Furthermore, PCCs as compared to CGPCs showed a statistically significant material-related decrease of Alfa ratings for criteria anatomic form and marginal discoloration. Kaplan-Meier survival analysis revealed a 93.3% cumulative survival rate for CGPCs and an 88.8% cumulative survival rate for PCCs after 5.5 years. Survival functions did not differ significantly across groups. At 5.5 years, CGPCs and PCCs exhibited satisfactory clinical outcomes. For PCCs, Bravo ratings increased significantly over time, however this did not compromise clinical survival of the restorations as compared to CGPCs.