Tooth preparation for full-coverage restorations-a literature review.

Abstract

The objective of this review was to assess the current knowledge about tooth preparation for full-coverage restorations regarding the following aspects: biological parameters, preparation geometry, and technical conditions. A systematic literature search was conducted using three electronic databases (MEDLINE, DIMDI, and Cochrane databases) in order to identify relevant citations; additionally, the process was augmented by a hand search. A number of 117 citations were relevant; 11 of these were reviews, 23 were clinical studies, 82 were in vitro investigations, and one was animal research. The basic form of a preparation has not changed substantially over the years, although new materials like all-ceramic systems have their own demands with regard to the details of the preparation's geometry. Estimating how much of the tooth structure can be removed without harming the tooth remains one of the biggest problems, if not the main difficulty, during tooth preparation. As the periodontal tissues may be affected by the restoration margin, a supragingival position of the margin should be preferred whenever possible. No finish line design has yet proven to be superior with regard to the marginal accuracy of the subsequent restoration. Instead, good detectability of the margin for the dental technician or intraoral scanning devices appears to be of primary importance in order to achieve a good fitting restoration. A detailed look at the covered aspects regarding tooth preparations can help to improve clinical outcomes in daily practice.