The influence of the attachment type and implant number supporting mandibular overdentures on stress distribution: An in vitro study, part I

Objectives: The main goal of this study was to compare the stress distribution of mandibular overdentures (OVD) with different numbers of supporting implants and single versus splinted attachment types. Materials and Methods: Four different biting situations were simulated for the 2-, 3-, and 4-implant retentive anchor as well as bar attachment OVDs on a formalinfixed cadaver mandible, and strains were recorded under vertical loading of 100 N. Results: The calculated von Mises values from measured strains in all measurement sites and loading conditions for nonsplinted attachments (retentive anchor) were higher than splinted (bar) attachments. Conclusions: It may be concluded that in cases with low quality and quantity of bone, the increase in number of implants and the use of a splinted attachment should be preferred to reduce forces emerging around the implants during function. The use of 2 single attachments in cases with good bone quality and ideal size implants still seems to be a safe and sufficient solution for the treatment of mandibular edentulism with OVDs. (Implant Dent 2013;22:39–48)