Assessment of Contact Pressures between a Mandibular Overdenture and the Prosthodontic Area

Abstract

In this paper, we assess the pressure between the overdenture located in the mandible and supported by a bar retained on two implants and the prosthodontic area. For testing, a model of an edentulous mandible was created using a mold by FRASACO with two implants and a “rider” bar inserted. A complete mandibular denture with polypropylene matrices was made. Three types of matrices of various stiffness were applied. The mandible and overdenture geometry was mapped using a digital image obtained with a Steinbichler Comet L3D 3D scanner. Finite element method calculations were performed in the Abaqus FEA software. The results demonstrate that the maximum contact pressure is observed when the loads are associated with canines. A critical case for the lower posterior is chewing performed by the molars. The pressure zone is the largest for POM-1 with Young’s modulus of 1.5 GPa and is reduced by 5.0% and 7.8% for POM-2 (E = 2.5 GPa) and POM-3 (E = 3.5 GPa), respectively. The stress distribution under the prosthesis mostly depends on the region loaded onto it. The applied load produces a slight contact pressure between the denture and the prosthodontic area in the anterior zone. A change in polypropylene matrix stiffness does not affect contact pressures.