EFFICIENCY OF RETENTION OF TWO ATTACHMENT DESIGNS USED FOR ALL ON FOUR MANDIBULAR INCLINED IMPLANTS ASSISTED OVERDENTURE

Abstract

Introduction: Reduction of retention should be considered when selecting an attachment for inclined implants following the all-on-four concept. Aim of the study: Evaluation the retentive force of mandibular implant-assisted overdentures with two different abutment designs following the all-on-four concept before and after cyclic loading. Material and methods: Two identical completely edentulous mandible models were made with epoxy resin. Anterior two implants were placed parallel to each other in the symphyseal area and two tilted implants were placed distally inclined with 25 degree angulation at canine-1st premolar region of each model by using a 3D Printed surgical guide. For group I (study group/1st model) OT-Equator abutment was connected to the anterior parallel implants and OT-Equator with smart box abutment was connected to the tilted implants. Group II (control group/2nd model) using OT-Equator abutment connected to the anterior parallel implants and angled positioner abutment connected to tilted implants. A universal testing machine was used to evaluatethe retentive force was of all overdentures with different attachments following the all-on-four concept before and after cycling loading then compared with control group. Results: When retentive forces of all overdentures with different attachments following the all-on-four concept before and after cyclic loading were compared, there was significant difference of retentive forces between different resilient caps which decreased after cyclic loading for both groups (p < 0.001). Conclusions: The OT-Equator with smart box attachment group showed greater value of retentive force compared with the Angled Positioner attachment group before and after cyclic loading.