Force transmission in bar-retained implant-stabilised mandibular over-dentures: an in-vitro study.

The effects of attachment clips on force transmission in two implant-stabilised over-dentures with cantilever extensions were investigated, using a previously developed in-vitro model, which simulated functional mandibular deformation. Two retentive configurations were used: an avoid gold bar cranked anteriorly with 13 mm distal cantilevers and the same configuration without attachment clips on the distal cantilevers. The dentures were loaded at individual tooth positions with a strain gauge beam and the forces exerted on the implants were measured using strain gauges mounted on their trans-mucosal abutments. The difference between the two retentive configurations was significant (P < 0.05) as tested by ANOVA. It is concluded that the retentive configuration without clips on the distal cantilevers results in a significant decrease in compressive forces on the implants.