Abstract: Objective  To compare the changes of biomechanical properties of mucosa and inferior alveolar bone of Class Ⅳ edentulous jaw of complete denture corresponding to anatomical occlusion and lingualized occlusion under two different load conditions of median occlusion and lateral occlusion. 
Methods The finite element model of the Class Ⅳ edentulous mandible was established, anatomical occlusion and lingualized occlusion were supplemented to the mandible, to simulate the median occlusion and lateral occlusion respectively. The biomechanical changes of the mucosa and alveolar bone were analyzed. 
Results Under the condition of median occlusion, the mucosal compressive stress of lingualized occlusion was smaller than of anatomic occlusion, and the decrease of mucosal compressive stress was about 0.6%-31.2%. The compressive stress on the upper surface of alveolar bone in the left molar area and anterior tooth area of lingualized occlusion was smaller than that of anatomic occlusion, and the decrease of alveolar bone stress was about 35.1%-19.0%, On the contrary, the alveolar bone compressive stress in the right molar area was 53.3% higher than that of anatomic occlusion. In the left lateral occlusal state, the compressive stress of lingualized occlusal on mucosa and alveolar bone decreased by 70.2%-41.1%. In the right lateral occlusal state, the compressive stress of lingualized occlusal on mucosa and alveolar bone decreased by 63.8%-24.4%. 
Conclusion In the restoration of Class Ⅳ edentulous jaw, the lingualized occlusion reduces the mucosal and alveolar bone compressive stress in the anterior tooth area and left molar area of the low flat alveolar bone of median bite compared with the anatomic occlusion type. And it is reduced in the anterior tooth area and bilateral molar area in the lateral bite, so as to provide a theoretical reference for clinical patients with severe mandibular alveolar bone resorption.

Key words: three-dimensional finite element, lingualized occlusion, anatomic occlusion