Effect of Locator and Telescopic Attachment on Retention value for Two-Piece and One-Piece Implant-Supported Palateless Maxillary Over Denture: An In-vitro study

Abstract

Objective: This study aims to evaluate the effect of two different implant designs (one-piece dental implant and two-piece dental implant) with attachment systems on retention value in implant-supported palate less maxillary overdenture. 
 Methods: Two edentulous maxillary models were fabricated from cold-cure polymethyl methacrylate resin. Four implants were inserted for each model as follows: Model I (Four one-piece implants were inserted, two implants in the canine region and two implants in the second premolar region), while Model II (Four two-piece implants were inserted, two implants in the canine region and two implants in second premolar region). The maxillary denture was constructed over each model. In model I, four ready-made titanium telescopic attachments corresponding to implant abutments were embedded in the inner surface of the overdenture. In contrast, in model II, four locator attachments corresponding to implant abutments were embedded in the inner surface of the overdenture. Initial anterior, posterior, and central retention values of overdentures were recorded and compared with the retention after 540 and 1080 cycles of insertion and removal using a digital force gauge. 
 Results: Statistical analysis revealed significant differences in the initial, secondary and tertiary retention values for anterior, posterior, and central retentions for both models (higher values were recorded before insertion cycles). The higher anterior and central retention values were recorded in Model II (44.93 and 25.9) N respectively, on the other hand, the higher posterior retention value was recorded for Model I 23.3N. 
 Conclusions: The type of attachment affects the retention value of maxillary overdenture. Continuous insertion and removal of the prosthesis lead to a decrease in the retention values.