ABSTRACT
The retention of a fixed prosthesis is one of the critical factors to prosthetic restoration long-term success. Obtaining a proper retention depends on several factors, such as the tooth preparation Convergence Angle (CA), which is formed by two opposite walls. The objective of this study was to measure the mesio-distal and bucco-lingual angles of tooth preparations for metal-ceramic crowns, performed by students from the Faculty of Dental Medicine, University of Porto, between 2013 and 2015. Study sample included 90 dies with preparations for metal-ceramic full crowns. Three groups were defined: anterior (43.3%), premolars (35.6%) and molars (21.1%). There were found statistically significant differences, between the three groups, in the mesial-distal CA (p<0.03) and also in buccal-lingual CA (p<0.001). Long-term studies are emergent to understand the influence of these larger CA values in the crown longevity.
