The Impact of Distal Cantilever Extension on the Stress Around FourImplants Connected by a Bar Retained Palateless Overdenture (In VitroStress Analysis)

Aim: This in vitro research was aimed to compare the impact of distal cantilever extension on the stress around four implants retained palateless overdenture by means of a bar. Materials and methods: Four implants were placed bilaterally in lateral incisor and the first premolar positions of edentulous acrylic resin maxillary model; connected bar with 7 mm distal cantilever extension with soft liner female retentive element was used. Eight strain gauges were bonded to the acrylic resin at the mesial and distal surfaces of each implant, stress was measured, then the 7 mm cantilever extension was trimmed and the stress measured for the bar without distal cantilever extension. Results: Bar with distal cantilever extension demonstrate a significant increase in stress compared to the bar without distal cantilever extension in unilateral loading and bilateral loading. During unilateral loading in bar with distal cantilever extension and bar without distal cantilever extension the maximum stress was recorded at mesial side of posterior implant of loading side. Conclusion: The four implants connected with the bar without distal cantilever extension demonstrates lower stress than bar with distal cantilever extension.