The Effect of Cement- Versus Screw-Retained Implant Positioning in the Esthetic Zone on Emergence Angle: A Proof-of-Principle Study.

Abstract

Choosing between screw-retained and cement-retained restorations in the esthetic zone may significantly impact the restorative contour. This study analyzes the effect of facial-palatal implant positioning on the facial emergence angle of implant restorations in the anterior maxilla. A total of 133 maxillary anterior implant cases were captured with intraoral scans and used to create digital prosthetic designs. The restoration facial emergence angle and the implant depth were determined using images at the midfacial 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 in emergence angle was found between screw-retained and cement-retained groups, with averages of 37.3 degrees and 27.9 degrees, respectively. There was no difference in the mean depth between the two groups. A strong negative linear relationship between depth and emergence angle was seen 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 a screw-retained position. This may be partially alleviated by deeper implant placement.