Three-year retrospective clinical evaluation of pulp-less molars with defects of varying degree repaired by cast ceramic onlays of three marginal types

Abstract

This study aimed to evaluate the clinical effect of pulp-less molars with defects of different degrees repaired by cast ceramic onlays of three marginal types. A total of 165 endodontically treated molars of 105 patients were included in this study and were divided into three kinds of defect (mild, moderate, severe) according to the number of remaining axial walls. Each defect was divided into three groups according to the shape of edge to edge, bevel edge, and concave shoulder. After tooth preparation, the casting of ceramic onlays was performed. Treatment follow-up was done for the evaluation of the success and survival rates of three groups under the same defect. The average follow-up was 925.44 days. Under the mild defect, the success and survival rates of the edge to edge onlays were respectively 100% and 100%; bevel edge onlays, 100% and 100%; and concave shoulder onlays, 94.4% and 100%. Under the moderate defect, the success and survival rates of the edge to edge onlays were respectively 96.0% and 100%; bevel edge onlays, 80.0% and 93.3%; and concave shoulder onlays, 95.2% and 95.2%. Under the severe defect, the success and survival rates of the edge to edge onlays were respectively 95.2% and 100%; bevel edge onlays, 73.7% and 89.5%; and concave shoulder onlays, 73.3% and 80.0%. Under different defects, the success or survival rates of the three kinds of onlays had no significant difference (P>0.05). The edge to edge type is the most preferable way of onlay tooth preparation and can achieve good clinical results in the mild, middle, and severe tooth defection with root canal treatment.