The Preliminary Development of a Friction-Based Lateral Screw-Retained Dental Crown—A Comparison between the Prototype Surface Treatment and the Retention Strength

Abstract

This study aims to develop a novel retention method combining the retrievability of the screw retention method with the ideal occlusal table and the aesthetic capability of cement retention. Coping was developed to have lateral screw access, allowing the screw to lock the coping using lateral forces from screw tightening and friction between the tip of the screw and the sandblasted surface of an abutment. Sandblasting parameters varied based on particle size. The results show a positive correlation to surface roughness and indicate a positive correlation to retention force. The highest surface roughness and retention force result was shown by groups that were sandblasted using 686 μm of aluminum oxide. Experiments on the tightening strength of 48 subjects measured in simulated conditions similar to the assembly conditions of lateral screw retention implants resulted in a mean of 69.75 Nmm with the highest and lowest values of 120.67 Nmm and 34.67 Nmm. This result became the basis of tightening torque variation. Each group’s retention capability is measured and compared to cement-retained dental implants. The results show that the tightening torque correlates positively with retention force, with the highest average retention score showed by lateral screws retained under a tightening torque of 200 Nmm—317.87 N higher than cement-retained screws.

Keywords

• lateral screw-retained
• retrievability
• retention
• dental implants