Department of Veterans Affairs Cooperative Studies Project No. 242. Quantitative and qualitative evaluation of the marginal fit of cast ceramic, porcelain-shoulder, and cast metal full crown margins. Participants of CSP No. 147/242.

The primary objective of Veterans Administration Cooperative Studies Program No. 242 was to evaluate, in vitro and in vivo, the suitability of new dental materials and techniques used in making crowns and fixed partial dentures. Because inaccurate margins can lead to changes in the periodontal tissues and/or to recurrent caries, it is important to assess the accuracy of margins resulting from the use of new, improved materials or techniques. This segment of the project compared the marginal fit associated with the use of Dicor Crowns, Cerestore crowns, and porcelain-shoulder metal ceramic full coverage restorations using both quantitative and qualitative methods. Statistically significant differences were found among these materials following analysis of the quantitative data. The ranking in mean marginal opening from smallest to largest was: metal margins (27.5 microns), Dicor crowns (63.5 microns), porcelain shoulder restorations (66 microns), and Cerestore crowns (75 microns). The rank order based on the qualitative evaluation method was the same.