A complete finite element model of a mandibular implant-retained overdenture with two implants: Comparison between rigid and resilient attachment configurations

PurposeThe aim of this study was to evaluate the influence of the retention mechanism on the behavior of a mandibular implant-retained overdenture (IRO) during the simulation of mastication. Therefore, a complete three-dimensional finite element model of a mandible with its IRO was developed.Materials and methodsThe geometry of the edentulous mandible and overdenture was generated from computed tomography. Two MKIII® implants (Nobel Biocare) with ball abutments and Dalbo Plus® (Cendres et Métaux) attachments were placed in the canine areas. Three foodstuff positions were analyzed for two retention mechanisms, “resilient” or “rigid”. Special attention was given to the modeling of the mandibular environment and of the existing contact between the different components. A probable muscular action was determined following the minimal work principle.ResultsThe food-crushing force was provided by masseters with a two-third/one-third ratio between working and non-working sides. The “resilient” configuration provided a wider contact area between the mucosa of the denture bearing area and the prosthesis. An increase of the mastication force transiting through the mucosa was also noted and lower stresses were observed in the bone surrounding implants.ConclusionResilient attachments allowed for an increase of the mastication load transiting through denture bearing surface. Furthermore, this study proposed an accurate model of the mandibular IRO, including its environment and faithful behavior reproduction.