Effect of placement of occlusive membranes on root resorption and bone regeneration during healing of circumferential periodontal defects in dogs

Previous studies indicate that root resorption is a frequent sequela to significant amounts of periodontal repair in animal models. A model was developed in labrador dogs to study periodontal wound healing in large circumferential defects in the absence of influence from the oral environment. A polytetrafluorethylene membrane of 1 micron pore size (GORE-TEX) was used to occlude cells from specific tissues from populating the healing dentin-connective tissue wound. 3 modalities were studied: (1) control, in which no membrane and therefore no cell occlusion was used, (2) flap occlusion, in which the internal surface of the flap was lined with the membrane preventing contribution of cells from the flap, (3) bone occlusion, in which the reduced alveolar bone was lined with the membrane preventing contribution from bone cells. Wound closure included total submergence of teeth and membranes. The membranes remained incorporated and no exposure of membranes or teeth occurred during the 3 months healing period. Histology revealed bone regrowth in all 3 treatment modalities. It is suggested that inductive elements in the connective tissue or dentin, or bone cells from periosteum were responsible for bone regrowth in the bone membrane treatment modality. No significant difference was seen for root resorption between the 3 treatment modalities. This study found that physical occlusion of cells from the inside of the surgical flap, or from the pre-existing bone, is not sufficient to prevent root resorption in periodontal wound healing.