Effect of position of single implant with two different attachments on stress distribution of mandibular complete overdenture (in-vitro study)

Abstract

Objective The aim of this in-vitro study was to evaluate the effect of position of single implant with two different attachments on stress distribution of mandibular complete overdenture using electrical resistance strain gauge. Materials and methods One acrylic mandibular edentulous model was constructed with 2 mm thickness of artificial mucosa. Four finished denture were obtained one denture for each group. Group 1: single implant at midline region with ball attachment. Group 2: single implant at midline region with locator attachment. Group 3: single implant at left canine region with ball attachment. Group 4: single implant at left canine region with locator attachment. Four strain gauges were cemented at distal, buccal, mesial, lingual aspect of midline and canine single implant to monitor the effect of the applied 50 N static. Unilateral vertical and oblique loads at three different sites central fossa of right first molar, midline and central fossa of left first molar over each implant inserted in the acrylic model. Results Midline single implant with locator attachment (group 2) during vertical and oblique load had lower stresses than ball attachment (group 1), but when implant at canine area with locator attachment (group 4) during vertical and oblique load had lower stresses than ball attachment (group 3). Comparing between midline and canine implant the lowest stresses obtained with (group 2). Conclusion (a) The locator attachment showed reducing stress on implant body ability to distribute the load than ball attachment in midline and canine region. (b) Single implant at midline region showed less stress than implant at canine region with both attachments. (c) Vertical load applied over mandibular overdenture retained by single implant showed less stress than oblique force for both attachments. Less strain value were recorded with the locator attachment in the midline region.