Retention and Wear Evaluation of Locator Attachment and Novaloc Attachments for Two Implant-Supported Mandibular Overdentures (In Vitro Study)

ABSTRACT This study aims to compare the retention and wear changes between two stud attachments “Locator” and “Novaloc” used for implant supported mandibular overdenture. Two ready-made epoxy resin models represented completely edentulous patients were prepared to receive two implant analogues in the canine area and divided randomly into two groups. The first group represented the Locator attachment with its nylon matrix and metal housing; the second one was Novaloc with its PEEK matrix. Two overdentures were constructed for each group. The pick-up proceeded as conventional method. Universal testing machine was used to measure the retention of each attachment. Chewing simulator exerted multiple cycles mimicking the insertion and removal of the overdentures at the baseline, 500 cycles, 1000 cycles, 1500 cycles and 2000 cycles. Digital microscope was used to evaluate the wear behavior of each attachment during these different cyclic loading. Regarding retention was performed by using Independent t-test which revealed that retention of group I (Locator) was significantly higher (P<0.05) than group II (Novaloc) at baseline, 500 cycles, 1000 cycles, 1500 cycles and 2000 cycles. Comparison between mean difference of wear (wear changes) of both groups was performed by using Independent t-test which revealed in the overall changes group I (Locator) was significantly higher than group II (Novaloc). The Locator showed higher initial retention than Novaloc. Regarding wear behavior, Novaloc showed lesser wear and changes than Locator attachment. Keywords: Locator attachment, Novaloc attachment, Retention, Wear.