Pressure Pain Threshold of Edentulous Oral Mucosa

When subjected to denture wearing, oral mucosa has to withstand load and engages in function as a mechanoreceptor. Denture treatment involves confounding problems derived from oral mucosal pain. Objective: This study investigated the pressure-pain threshold (PPT) of oral mucosa in edentulous patients. Methods: A hand-held pressure algometer consisting of a pressure sensitive strain gauge and a signal recognizing hold switch was specially developed for the assessment of PPT of oral mucosa. A connected personal computer allowed a visualization of magnitude and duration of applied force and their control. The PPT was measured at 9 regions (6 on the maxilla, 3 on the mandible) of 6 edentulous patients at 50 gf/s of the pressure rate. The regions of PPT measurement were determined based on anatomical landmarks and tooth location anticipated from the data of 20 dentate subjects. Results: One-factor ANOVA revealed a significant effect of the region on the PPT both in the maxilla and mandible (p<0.05). In the maxilla, the PPT was greater at the molar region than the incisor region and hamular notch. The PPT was over 2-fold higher at the hard palate than soft palate. In the mandibular ridge area, the PPT rate was in the order retromolar pad > molar region > incisor region. The retromolar pad exhibited a PPT twice as great as the incisor region. Conclusion: The edentulous oral mucosa shows region-specific PPT, suggesting a region-specific physiologic resistance of oral mucosa against mechanical load. Accumulating these data would serve as a basis for understanding roles of oral mucosa as a denture supporting tissue and mechanoreceptor.