Development of New Attachment System with Soft Lining Material for Implant-retained Complete Denture

Abstract

Purpose: The retention of complete dentures is frequently difficult in edentulous patients with a severely resorbed residual alveolar ridge. In such cases, implant overdentures having a stronger retention force are useful. Although there are various types of attachment systems for implant overdentures, they are frequently complicated. We are, therefore, developing a simple attachment system focusing on a soft lining material for the female connector. The purpose of this study was to evaluate the retention force of implant overdentures applying a soft lining material for the attachment. Materials and methods: The models in which seven male and female connector pairs were used. As the control, a rubber O-ring attachment system, in which a rubber O-ring female was paired with a metal ball anchor (male), having a diameter of 1.7 or 2.2 mm. In the attachment system with a soft lining material, a female component was made up of soft lining material paired with a male having a diameter of 1.7, 2.2, 2.5, 2.7 or 3.0 mm. In measuring the retention force, the maximum force required to dislodge the male from the female was recorded by a digital force gauge. Results: With the rubber O-ring, the retention force was 2.9 ± 0.2 N for the 1.7 mm male and 3.3 ± 0.3 N for the 2.2 mm male; these values were higher than the respective retention forces when using a soft lining material as the female and a male of the same diameter. However, with the female comprising soft lining material, the retention force exceeded 4 N for the 2.5, 2.7 and 3.0 mm males and was higher than the retention forces for the rubber O-ring. Conclusion: The proposed attachment system with soft lining material for implant overdentures provides a clinically sufficient retention force when the diameter of the male exceeds 2.5 mm.