Adhesively luted, metal-free composite crowns after five years

The effect of location and preparation design of abutment teeth and of preparation design on the survival and complication rate of metal-free, adhesively luted composite crowns (Artglass, Heraeus Kulzer) and their clinical performance was investigated in this controlled, randomized, prospective clinical study.

After randomization, 114 single crowns (68 posterior, 46 anterior) were prepared either with a 0.5 mm chamfer finishing line or with a 0.5 mm shoulder combined with occlusal reduction of at least 1.5 mm. Buildups were made with a composite material, using the corresponding dentin adhesive. Crowns were manufactured on stone dies and intraorally adhesively luted with resin cement. Follow-up examinations were conducted after 1 month and 1, 2, 3, and 5 years. Documentation included failures and complications, occlusal contacts, plaque accumulation and patients' rating of esthetics and functionality. After 5 years, data for 83 single crowns had been obtained.

Within an observation period of 5 years, 18 complications occurred, including 13 major failures which resulted in replacement of the crowns, and 5 minor complications which could be repaired. All loosened crowns (n = 2) were successfully re-cemented. The Cox Regression did not reveal any effect of location or preparation design on complication rate. Calculation of the Kaplan-Meier survival curve on the basis of major failures indicated a probability of survival of 96% after 3 years and 88.5% after 5 years. Four Artglass crowns had no contact in static occlusion after 5 years and plaque accumulation was significantly higher than for control teeth. esthetic and functional evaluation by patients revealed that acceptance was high.

Metal-free composite crowns may be recommended for long-term temporary use. However, the complication rate and the increased plaque accumulation restrict the indication for permanent restorations.