Pressure stress area of mandibular alveolar mucosa under complete denture

Objective: To analyze and compare vertical (Z-axis) pressure stress areas of mandibular alveolar mucosa under linear and anatomic complete dentures at lateral occlusion.

Methods: Computer tomography and finite element analysis (FEA) were performed to set up 3-dimensional FEA models of maxillae and mandibles with severe residual ridge resorption (RRR), mucosa, and linear and anatomic occlusal complete dentures. Stress areas were calculated by FEA, and we compared the data of two occlusal schemes involving complete dentures loaded with imitative masticatory forces.

Results: At lateral occlusion, the anatomic working-side stress area between -0.07and ~ -0.1 MPa was larger than the linear one on the molar area. The linear working-side stress area between -0.03 and ~ -0.07 MPa was 1.33-fold that on the anatomic side. At the balancing side, the linear occlusal stress area between -0.03 and ~ -0.07 MPa was 2.4-fold the anatomic one. Considering the total stress distribution area of mandibular mucosa under vertical pressure, linear occlusion was 1.2-fold that on the anatomic side.

Conclusions: At lateral occlusion, the vertical stress area of mandibular mucosa under linear occlusal complete denture was larger than the anatomic one, which indicates that vertical stress distribution under the linear occlusal complete denture is more comprehensive, which may be of benefit for better denture stability.