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

This report describes observations of healing following guided tissue regen eration (GTR) including surgical implantation of the prostaglandin E1 analo g misoprostol with calcium-layered methacrylate particles. Critical size, s upra-alveolar periodontal defects wen surgically created around the 3rd and 4th mandibular premolar teeth in 4 beagle dogs. Wound management included soaking with a 24 mu g/ml misoprostol solution and implantation of the miso prostol/methacrylate composite. One jaw quadrant per animal was prepared fo r GTR using expanded polytetrafluoroethylene membranes. The gingival flaps were coronally advanced and sutured to submerge the teeth. The tissues cove ring the surgical sites daily received topical misoprostol in an oral adhes ive over the 4-week healing interval. Upon euthanasia, tissue blocks were p repared for histometric analysis of regeneration of alveolar bone and cemen tum, root resorption and ankylosis. The defect area underneath the membrane and the density of methacrylate particles were recorded for the GTR defect s. The methacrylate particles appeared encapsulated in a dense connective t issue without signs of an inflammatory reaction, some in contact to newly f ormed bone. Alveolar bone regeneration height averaged (+/-SD) 1.2+/-1.0 an d 1.0+/-0.6 mm for GTR and non-GTR defects, respectively. Corresponding val ues for bone regeneration area were 1.3+/-1.0 and 0.7+/-0.5 mm(2). Cementum regeneration was confined to the apical aspect of the defects. Small areas of root resorption and ankylosis were observed for all teeth. Bone regener ation area correlated positively to the defect area and negatively to the d ensity of methacrylate particles in the GTR defects. The histologic observa tions suggest that the methacrylate composite has marginal potential to pro mote bone and cementum regeneration under provisions for GTR.