Ridge Remodeling after Tooth Extraction in Rats

¹ University of Illinois College of Dentistry, Chicago, Illinois

The healing process and the resorption pattern of the edentulous ridge after tooth extraction was studied in 32 young hooded rats over 8 weeks. Several variables were analyzed: single tooth extraction as compared with multiple tooth extractions; healing in the maxilla as compared with healing in the mandible.

The rate of healing was the same when either one or two adjacent molar teeth were extracted. The rate of healing was slower in the maxilla than in the mandible.

The alveolar crest resorbed after tooth extraction, whereas the socket region within the residual basal bone filled in with new bone. The alveolar crest appeared to be delineated from the basal bone by the muscle attachment on the external bony surfaces. The muscle attachments involved were those of the buccinator on the buccal aspect of the maxilla and mandible, and of the mylohyoid on the lingual aspect of the mandible.

The shape of the residual bony ridge was determined by the location of the muscle attachments at the borders of the ridge.

The new epithelium covering the edentulous surface showed thinner and flatter rete pegs and a smoother keratinous layer than the old epithelium at the borders of the wound.

The surface contour of the edentulous ridge was determined by the amount of scar tissue located between the epithelium and the residual bone.