Is anterior guidance a key factor on planning implant treatment for free-end missing in the posterior mandible?

To perform safe implant treatment, the anatomical structure and bone quality at implant placement sites are evaluated based on a patient's CT data, but there is no definite method to determine placement sites and the appropriate number of implants. The objective of this study was to investigate the influence of the number and arrangement of implants on the stress distribution in 3-unit posterior fixed partial dentures for the posterior mandible by mechanical analysis using the finite element method. Three-dimensional finite element analysis models were constructed from the CT data of a patient with missing mandibular teeth (Nos. 35, 36, 37). Implant placement was simulated under various conditions. Superstructures were connected and fixed with a titanium frame. As the loading conditions, 400 N vertical and lateral loads (45 degrees on the lingual side and 45 degrees on the buccal side) were applied to the upper areas of Nos. 35, 36, and 37, and the stress distribution and frame displacement were evaluated...