Number and Location of Mini-Implants Retaining a Mandibular Overdenture to Resist Lateral Forces: A Preliminary In Vitro Study

Purpose: The aim of this study was to determine the optimal number and location of miniimplants retaining an overdenture to resist lateral forces. Materials and Methods: A strain gauge was attached to a mini-implant and placed in an edentulous mandible model. The following different implant locations were evaluated: one mini-implant at the midline, two miniimplants in the lateral incisor regions, two mini-implants in the canine regions, and four miniimplants. Results: Lateral forces on mandibular overdentures retained by one mini-implant at the midline or two mini-implants in the lateral incisor regions appeared to be advantageous when compared with placing two mini-implants in the canine regions or four mini-implants. Conclusion: Fewer mini-implants resulted in less lateral stress, while four were associated with an unequal stress distribution.