Repair restorations: Questionnaire survey among dentists in the Canton of Zurich, Switzerland.

The aim of this study was to carry out a representative survey on the implementation of and experience with repairs of single-tooth restorations among dentists in the Canton of Zurich, Switzerland. An anonymous questionnaire was sent to all 1,411 dentists registered in the Canton of Zurich; 38.9% of the delivered questionnaires were returned and 35.3% could be evaluated. The statistical analysis comprised Kendall’s rank correlation coefficient (tau), Wilcoxon signed-rank tests, and Kruskal-Wallis tests. The level of significance was set at p≤0.05. Repair restorations are frequently made (composite: 98.5%, ceramic: 88.9%, crowns: 86.5%, metal: 54.6%, amalgam: 51.5%). Main indications for repairs were the partial loss of an existing restoration or of the adjacent dental hard substance, while restoration failures due to secondary caries were repaired to a lesser extent. The decision to repair is largely dependent on the size of the defect (90%), the size of the original restoration (63%), and the material of the failed restoration (84%). Repair restorations are most frequently made with composite following adequate conditioning of the repair surface. A majority of the dentists rate the lifespan of repair restorations as reduced in comparison with newly made restorations. In summary, repairs of defective single-tooth restorations are frequently performed by dentists in the Canton of Zurich, Switzerland, and constitute a well-established treatment procedure.