Influence of finish-line geometry on the fit of crowns.

Previous studies on the fit of complete crowns have neglected to assess the internal adaptation of castings prior to cementation. Theoretical arguments and laboratory studies have failed to clarify which is the most desirable finish-line configuration in terms of marginal fit. This study evaluated axial and marginal fit of crowns made for three tooth preparations that had different labial finish-line configurations: shoulder, shoulder-bevel, and chamfer. The crowns were not cemented, but were sectioned and examined on their respective dies. There were no significant differences (P < or = .05) among groups for marginal or axial gaps. Crown fit was not influenced by any of the three finish lines tested, and castings with well-fitting margins exhibited measurable axial wall space.