Histologic studies on the structure of the residual ridge in the edentulous mandible

Abstract

Histologic observations of the mandibular bone and the overlying mucosa in the edentulous individuals were made. Sections of the premolar and molar regions of the edentulous mandible from ten cadavers ranging from 65 to 100 years old were microscopically observed. Buccolingual sections revealed that the shape of the residual ridge surfaces inclined in the middle at about the upper one-third portion of the mandibular bone. The buccal site of the mandibular bone consisted of the trabeculae and new bones around them, instead of the original cortical plate. The lingual site consisted of the corticis and new bones in the inner and upper portion. The direction of the trabeculae was parallel to the inner surface of the cortex and curved toward the middle of the mandibular bone. It was observed, however, that the trabeculae were mainly arranged from the lingual anterior portion to the buccal posterior portion in the horizontal section. Submucosa was not found at the crest of the residual ridge, and dense fibrous connective tissues and fiber bundles arranging mesiodistally were found in the lamina propria. On the other hand, submucosa and less dense fibrous connective tissues were observed in the buccal and lingual portion of the residual ridge.