Survival of Dicor glass-ceramic dental restorations over 16 years. Part III: Effect of luting agent and tooth or tooth-substitute core structure

Statement of problem. The influence of different types of restorative design features on the long-term survival of Dicor glass-ceramic restorations is only partially understood. Purpose. This study examined the effect of different types of luting agents and preparation core structures on the survival of Dicor glass-ceramic restorations functioning in vivo. Material and methods. A total of 1444 Dicor glass-ceramic restorations were placed on the teeth of 417 adults. Failure was defined as a restoration that required remake because of material fracture. The survival of restorations of different types, with different luting agents and preparation core structures, was described with Kaplan-Meier survival functions. The significance of differences in survival between different tooth or tooth-substitute preparation core structures and different luting agents was determined with the log-rank test. Results. The probability of survival of a typical acid-etched Dicor restoration luted to gold preparation core structures was 91% at 16 years compared with 75% for dentin preparation core structures (P < .01). The survival of acid-etched Dicor restorations luted to dentin preparations,vas significantly better than nonacid-etched restorations luted to dentin. Acid-etched Dicor restorations luted with resin composite exhibited a more favorable survival function than those luted with glass ionomer P < .01) and zinc phosphate ( P < .05). Differences between restorations luted with glass ionomer or zinc phosphate agents were not significant. Conclusion. Acid-etched Dicor restorations luted to gold preparation core structures exhibited significantly better intraoral survival than restorations luted to dentin. Acid-etched Dicor restorations survived better than nonacid-etched restorations when luted to dentin preparations. Acid-etched Dicor restorations luted with resin composite exhibited more favorable survivor functions than restorations luted with glass ionomer or zinc phosphate agents.