Six-year survival of single crowns - A massive data analysis

Abstract

Objectives: Numerous clinical trials have proven the long-term stability of metal and metal-ceramic crowns. However, data on their performance under practice conditions are rare.

Purpose: To evaluate the longevity of crowns by means of massive data analyses.

Methods: The data were extracted from the data warehouse of a major German national health insurance company (BARMER, Berlin, Germany). The analysis focused on crown types with the lowest deductibles. Metal crowns and metal-ceramic crowns with ceramic veneering on the vestibular aspects of teeth 15-25 and 34-44 placed from 2012 to 2017 were included. The placement of the crowns, crown removals and tooth extractions were identified using the corresponding fee codes. Kaplan-Meier survival analyses were conducted for the outcomes "crown removal or extraction" and for "extraction".

Results: The cumulative six-year survival rates were 88.0 % for the outcome "crown removal or extraction" and 92.5 % for the outcome "extraction" (N = 192,868). The survival functions had slightly steepening but close to linear courses.

Conclusions: The outcome of the treatment with metal and metal-ceramic crowns was moderately inferior in comparison to clinical trials. However, treatment with metal and metal-crowns is judged to be a reliable and safe option under practice conditions.

Clinical significance statement: Clinicians must inform patients about potential treatment outcomes. Therefore, additional knowledge about single crown outcomes under general practice settings based on large database analyses is important.

Keywords: Crowns; Data mining; General practice; Health services research; Prosthodontics; Treatment outcome.