Influence of crowns on the extraction of root filled teeth

Objectives:

The purpose of this study was to compare the survival of root filled teeth which have been restored with direct restorations or crowns.

Methods:

For each patient on the database with a tooth restored with a direct or indirect restoration with or without a root filling, the subsequent history of intervention on that tooth was consulted, and the date of extraction, if this could be found in the data set, was obtained. Thus a data set was created of teeth restored with direct restorations or crowns and whether they have also received root fillings, with the dates of restoration and root filling placement and the dates, if any, of extraction.

Modified Kaplan-Meier statistical analysis was used to quantify the distribution of time to intervention.

Results:

Data for over 80,000 different adult patients were analysed, of whom 46% were male and 54% female. 491,404 teeth with direct restorations of the crown were identified of which 22,434 had root fillings, 47,563 with indirect restorations were identified, of which 7,639 had root fillings. In each group the root filled teeth performed less well, with crowned root-filled teeth surviving longer to extraction than root filled teeth with directly placed restorations (p<0.0001).

Conclusions:

Examination of the survival of teeth with and without root fillings has indicated that those with root fillings restored with direct restorations have shorter intervals to extraction than teeth with root fillings restored with crowns.

The support of the NHS Business Services Authority (Dental Practice Division) is acknowledged.