The effect of cement versus screw-retained implant positioning in the esthetic zone on emergence angle: A proof of principle.

Abstract

Choosing between screw-retained and cement-retained restorations in the esthetic zone may have a significant implication on the restorative contour. This study analyzes the effect of facial-palatal implant positioning on the facial emergence angle of implant restorations in the maxillary anterior region. 133 maxillary anterior implant cases were captured with intraoral scans and used to create digital prosthetic designs. The facial emergence angle of the restoration and the depth of the implant were determined using images at the mid-facial cross-section. Simple logistic and linear regression models were used to analyze the interrelation between the emergence angle, depth, and retention methods. The average facial emergence angle for all restorations in this study was 34.4 degrees. A significant difference was found in emergence angle between screw-retained and cement-retained groups, with an average emergence angle of 37.3 degrees and 27.9 degrees, respectively. There is no difference in the mean depth between those two groups. There is a strong negative linear relationship between depth and emergence angle for the screw-retained group. Overall, implant positioning in the anterior maxilla has a significant influence on emergence angle. Facial emergence angle is significantly greater for implants in screw-retained position. This may be partially alleviated by deeper implant placement.