The use of crowns and fixed partial dentures to restore severely broken down teeth and replace missing teeth has increased dramatically over the last decade. Currently, the placement of these restorations accounts for almost 15 billion dollars of the total annual expenditures for dental care by the consuming public. However, the long term effects of the procedures involved in crown fabrication on the vitality of pulp tissue has not been evaluated.
The specific aims of this retrospective study are to determine the incidence of and factors contributing to pulpal necrosis in teeth that have been restored with crowns and/or fixed bridges. This will be accomplished by examining patients who have received these restorations in the under-graduate, graduate, and Faculty Practice clinics over the past decade. A sample size of 500 patients will be clinically examined by a Prosthodontist and an Endodontist in order to determine the prevalence of pulpal necrosis following permanent cementation of each prosthesis. Data will be collected regarding previous restorative history, previous materials utilized, and the experience level of the operator rendering the service. The condition of the dental pulp will be assessed on the basis of patient histories of painful symptoms, and to the response of crowned teeth to electric pulp tests, percussion, and CO2 ice pencil as compared to adjacent or contralateral non-crowned controls. Periodontal health will be assessed utilizing several indices. Periapical radiographs will be taken to confirm pathology. Standard statistical software packages (SAS) will be used to perform multivariate and univariate analyses which will be used to assess pulp pathology as a variable of crown type, materials used in the fabrication of the prosthesis, length of time required for completion of the restoration, experience level of the operator, and intra-observer reliability. It is anticipated that this investigation will provide a data base for establishing the incidence of pulp pathology resulting from crown and/or bridge placement. It is also anticipated that these data will provide a quantitative means for establishing prediction factors for determining which teeth will require endodontic intervention prior to crown preparation and placement. Additionally, these observations should reveal how teeth react to full coverage restorations over a period of time. This information will form the basis for future research involving the effect of microleakage under crowns and bridges on long term pulp vitality.
