A 4-year clinical study on amalgam, resin composite and resin-modified glass ionomer cement restorations in overdenture abutments

Objective: To assess the performance of three different filling materials in overdenture abutment teeth. Methods: In 49 patients amalgam, resin composite and resin-modified glass ionomer cement were used to seal the root canal orifices of 155 overdenture abutment teeth. After initial preparation of the cavities, the three restorative materials were randomly assigned to the abutment teeth using a number of balancing criteria. All patients were reviewed every six months and received the same preventive regimen. Survival was assessed at two levels: S orig (survival of the restoration independent from eventual maintenance treatments) and S comp (restorations survived even without maintenance treatments). Results: The calculated overall survival percentage of the original restorations ( S orig) after four years was 63±6% (mean±SE). Calculation for the overall complete survival ( S comp) revealed a percentage survival of 57±6%. At both levels, the differences between the survivals of the investigated materials were not statistically significant ( p-values>0.05). Two abutments were lost, severe caries was the reason for one extraction and another abutment tooth was extracted for periodontal reasons. Conclusions: The results of this study did not point out a superior restorative material for the seal of root canal orifices of overdenture abutments. The distribution of failures over the patients indicates a certain patient dependency.