Biomechanical Analysis of Denture Base Materials in Mandibular Complete Dentures

Objectives: The purpose of this study was to evaluate the stress distribution in the mandibular complete denture, mucosa, and bone under different loading conditions and denture base materials.
Methods: 3D finite element models were made of the mandible, soft tissue, mucosa, denture base, and denture teeth using CT, DICOM, and STL data. Models were created using a mesh generation program (Visual-Mesh; ESI Group). 18 simulations were designed each with a different denture base material [polymethylmethacrylate (PMMA), polycarbonate (PC), and polyamide (PA)], load direction [vertical and oblique (45°)] and static loads (50 N, 100 N and 150 N), respectively. Loads were distributed to the posterior teeth: buccal slope of the buccal cusp, lingual slope of the buccal cusp, and buccal slope of the lingual cusp, respectively. Maximum von Mises stress and displacement values were then compared and analyzed.
Results: Considering the stresses (MPa) in the cortical bone at 150 N (oblique), PMMA demonstrated having the least stresses at 6.0, with both PC and PA showing comparable values at 11.1 and 11.3, respectively. All materials exhibited maximum stresses anteriorly at 150 N (oblique) loads, whereas vertical loading displayed the highest stresses anterior to the right retromolar pad region – PMMA (6.2), PC (8.5), and PA (6.4). The extent of mucosal displacements (µm) at 150 N (oblique) for PMMA, PC, and PA were 55.4, 96.1, and 119.0, respectively. The degree of prosthesis displacements, likewise, followed the same trend, with maximum stresses all occurring at the denture’s most posterior flange on the right side.
Conclusions: In terms of stress distribution and displacement, PMMA performed superiorly than PC and PA. These two thermoplastic resin denture bases have lower modulus of elasticity which may be susceptible to dimensional instability, and may consequently affect biomechanical performance. However, both can be used as an alternative material for patients who are hypersensitive to PMMA.