The effect of tooth preparation design on the CAD/CAM all-ceramic coping crown's fitness / 中华口腔医学杂志

ABSTRACT

<p><b>OBJECTIVE</b>To study the effect of tooth preparation design on fitness of CAD/CAM all-ceramic coping crown.</p><p><b>METHODS</b>The tooth preparation comprised 2 types of occlusal convergence (10 degrees, 20 degrees), 2 margin forms (shoulder, chamfer). The MC coping were milled by Cerec 2 CAD/CAM system, cemented, embedded, sectioned, and measured at 10 sites to obtain the data of margin, shoulder, axial surface, occlusal surface fitness.</p><p><b>RESULTS</b>The coping's fitness was influenced by convergence angle and margin form. The coping's fitness was very nice (101.7 approximately 127.9) microm when the coping with 20 degrees occlusal convergence angle. Those coping with 20 degrees occlusal convergence and chamfer margin in tooth preparation provided the best fitness, its cement film thickness in margin was (40.1 +/- 11.8) microm.</p><p><b>CONCLUSIONS</b>The 20 degrees occlusal convergence and chamfer margin can be used for CAD/CAM all-ceramic crown in clinical application.</p>