HEALING RESPONSE TO ANORGANIC BONE IMPLANTATION IN PERIODONTAL INTRABONY DEFECTS IN DOGS .1. BONE REGENERATION - A MICRORADIOGRAPHIC STUDY

THE PURPOSE OF THE PRESENT STUDY was to explore the regenerative poten tial of anorganic bone plus collagen (AB-C) in experimental intrabony defects. Eight healthy female beagle dogs, 3 to 4 years old and weighi ng 15 to 16 kilos, were used. After extraction of the mandibular third premolars (P3), surgical defects were created and inflammation induce d by placement of cotton and steel braids. Eight weeks later, the brai ds were removed. The experimental lesions thus obtained were either tr eated by plain flap curettage (group 1: control) or were, in addition, implanted with AB-C (group 2: experimental). Blocks of AB-C alone wer e observed by scanning electron microscopy (SEM). The results show tha t the surface of the particles have the characteristics of a bone tiss ue. These particles are gathered together with a fibrillar network. Si x, 18, and 36 weeks postoperative (PO), non-decalcified specimens from both groups were examined histologically by contact microradiography. In group 1? no significant bone regeneration was observed at 6, 18, o r 36 weeks PO. In group 2, trabeculae undergoing mineralization and ci rcumscribing dense particles above the reference notch were seen at 6 weeks PO; 18 and 36 week specimens showed significant bone regeneratio n with more or less dense remaining particles, The periodontal ligamen t space was always clear and the only signs of ankylosis noticed were deep in the notch on one 18 week group 2 specimen and on one 36 week g roup 1 specimen.