Six-Year Survival of Single Crowns – a Massive Data Analysis

Objectives: Aim of this study was to evaluate the six-year survival of single crowns under practice conditions using a large insurance database.
Methods: This retrospective study based on claims data from the database of a major German national health insurance. The responsible research ethics board approved the study design. Fee codes and treatment dates allowed for tracing clinical courses. Only data from patients who had been members of the insurance for the whole six-year period 2012 to 2017 were included. The sample consisted of metal crowns on all teeth with optional ceramic veneering on the vestibular aspect of incisors, canines and premolars (except for teeth 35 and 45). Statistical Methods comprised Kaplan-Meier-survival-analyses. Primary Outcomes were crown removal and tooth extraction.
Results: A number of 193,704 teeth could be traced. The cumulative six-year survival rates were 92.2 % for the outcome crown removal and 92.3 % for the outcome extraction.
Conclusions: This study confirmed a good mid-term sustainability for single crowns under the terms and conditions of the German national health insurance system. Striking differences from results of clinical studies were not visible.