Assessment of CAD-CAM zirconia crowns designed with 2 different methods: A self-controlled clinical trial

Abstract

Statement of problem: In computer-aided design and computer-aided manufacturing (CAD-CAM) dentistry, the correlation method is an efficient way to design complete crowns. However, the occlusal relationship and patient satisfaction with prostheses fabricated using this method remain unclear.

Purpose: The purpose of this clinical trial was to compare the occlusion of monolithic zirconia crowns designed using the correlation and library methods.

Material and methods: Twenty-three teeth of 21 participants received 2 monolithic zirconia crowns designed by using the correlation or the library method. Defective teeth were scanned using an intraoral scanner to obtain references and working casts from before and after the preparation. Before cementation, the occlusal relationship of both crowns and patient satisfaction were evaluated, and the occlusal adjustment time was recorded.

Results: The correlation method resulted in less lateral occlusal interference of the crowns than the library method (P<.01). The occlusal adjustment times of the correlation and library conditions were 455.8 ±357.1 seconds and 575.3 ±488.0 seconds, respectively (P>.05). Relative occlusal force was significantly higher in the correlation than in the library condition and was related to before preparation relative occlusal force (r=0.706, P<.01). The visual analog score before occlusal adjustment was higher in the correlation than in the library condition (P<.05). The occlusal contacts, occlusal contact distributions, and number of occlusal contacts did not differ between conditions (P>.05).

Conclusions: Better eccentric occlusion and reduced lateral occlusal interference were obtained when the correlation method was used to design crowns. The correlation method yielded higher relative occlusal force, which helped to restore the original occlusal force.