Periodontal repair in dogs: histologic observations of guided tissue regeneration with a prostaglandin E1 analog/methacrylate composite

Abstract

This report describes observations of healing following guided tissue regeneration (GTR) including surgical implantation of the prostaglandin E1 analog misoprostol with calcium-layered methacrylate particles. Critical size, supra-alveolar periodontal defects were surgically created around the 3rd and 4th mandibular premolar teeth in 4 beagle dogs. Wound management included soaking with a 24 microg/ml misoprostol solution and implantation of the misoprostol/methacrylate composite. One jaw quadrant per animal was prepared for GTR using expanded polytetrafluoroethylene membranes. The gingival flaps were coronally advanced and sutured to submerge the teeth. The tissues covering the surgical sites daily received topical misoprostol in an oral adhesive over the 4-week healing interval. Upon euthanasia, tissue blocks were prepared for histometric analysis of regeneration of alveolar bone and cementum, root resorption and ankylosis. The defect area underneath the membrane and the density of methacrylate particles were recorded for the GTR defects. The methacrylate particles appeared encapsulated in a dense connective tissue without signs of an inflammatory reaction, some in contact to newly formed bone. Alveolar bone regeneration height averaged (+/-SD) 1.2+/-1.0 and 1.0+/-0.6 mm for GTR and non-GTR defects, respectively. Corresponding values for bone regeneration area were 1.3+/-1.0 and 0.7+/-0.5 mm2. Cementum regeneration was confined to the apical aspect of the defects. Small areas of root resorption and ankylosis were observed for all teeth. Bone regeneration area correlated positively to the defect area and negatively to the density of methacrylate particles in the GTR defects. The histologic observations suggest that the methacrylate composite has marginal potential to promote bone and cementum regeneration under provisions for GTR.

Prostaglandin E2 enhances alveolar bone formation in the rat mandible

“…The duration of the remodeling cycle in the mandibular alveolar bone is shorter than in the long bones [18]. In the long bones, the remodeling cycle is 20-30 days [7], whereas in the alveolar bone, it is 6 days plus a 5-day resting period [17].…”

“…Particularly as local delivery of prostaglandin E1 (PGE1) has been shown to enhance the formation of mandibular alveolar bone, reorganization of adjacent cells in the periodontal ligament and cementum formation [11,13,18]. The positive effect of PGE 2 on bone deposition has been reported with doses as low as 1 mg/kg per day delivered subcutaneously into different animal models over extended periods of time [1,6,9,20].…”

Periodontal Repair in Dogs: A Bioabsorbable Calcium Carbonate Coral Implant Enhances Space Provision for Alveolar Bone Regeneration in Conjunction with Guided Tissue Regeneration

“…5,6,8,9 Collapse or compression of the barrier device into a periodontal defect or onto the root surface will necessarily compromise regeneration of alveolar bone and cementum following GTR procedures. [4][5][6][7][8][9] The space provided by the device at the time of surgery is lost and the device becomes a physical obstacle to bone and cementum regeneration. Thus, structurally reinforced GTR devices have been developed to safeguard wound stability and maintain necessary space provision.…”

“…2,3 Studies have also shown that alveolar bone and cementum regeneration is critically dependent on space provision by the GTR device. [4][5][6][7][8][9] With limited space provision by the barrier membrane, alveolar bone will fill the space provided by the device. 4,9 In presence of a larger space, the alveolar bone adopts a physiologic form along the entire root surface, the remainder of the space being filled by fibrous connective tissue.…”

“…These characteristics have been shown to support alveolar bone and cementum regeneration in the supraalveolar periodontal defect model. [4][5][6][7][8] ePTFE sutures** were used for membrane fixation and wound closure.…”