Re-interventions after restoring teeth-Mining an insurance database

Abstract

Objectives: The aim of this study was to examine re-interventions after restorative treatment.

Methods: The data was collected from the digital database of a major German national health insurance company. Only permanent teeth were observed. Placing a permanent restoration other than a crown regardless of involved surfaces and material was the study intervention. The data did not allow for a differentiation between fillings and inlays that were estimated only a very small portion of the restorations. Success was defined as not undergoing any restorative re-intervention with fillings or inlays on the same tooth (primary outcome) and assessed with Kaplan-Meier survival analyses over four years. An additional analysis was conducted rating "crowning" and "extraction" of respective teeth as target events. Differences were tested with the Log-Rank-test. A multivariate Cox regression analyses was carried out.

Results: A total of 17,024,344 restorations placed in 4,825,408 anterior teeth and 9,973,177 posterior teeth could be traced. Focussing on the primary outcome re-intervention, the cumulative four-year success rate was 69.9% for one surface restorations, 74.8% for two surface restorations, 66.6% for three surface restorations and 61.0% for four surface and more extended restorations. These differences were significant (p<0.0001). Focussing on all three target events re-intervention, crowning and extraction, the cumulative four-year success rate was 66.1% for one surface restorations, 67.5% for two surface restorations, 63.0% for three surface restorations and 55.8% for four surface and more extended restorations. The number of restoration surfaces as well as the tooth position remained significant in the multivariate Cox regression.

Conclusions: The sustainability of restorative dental treatment under the terms and conditions of the German national health insurance system shows room for improvement. From a public health perspective, special focus should be laid on primary and secondary prevention to minimize the restorative treatment need.

Clinical significance statement: This study shows that re-interventions are observed regularly after restorative treatment. Therefore, preventive and restorative strategies should be revisited and optimised.

Keywords: Dental restoration (permanent); General practice (dental); Health services research; Operative dentistry; Public health; Treatment outcome.