Guided tissue regeneration in surgically-produced furcation defects. An experimental study in the beagle dog.

The aim of the investigation was to evaluate the potential for new attachment formation at various degree III furcation involvements in the beagle dog. 3 differently shaped furcation defects were prepared; one small and one large key-hole defect, and one furcation defect which was part of "circumferential" loss of attachment and bone. 15 beagle dogs were used in the experiments. The furcation defects were surgically created at mandibular premolars in the right and left side of the jaw. Test teeth were subsequently treated according to the GTR principle, while control teeth were treated without the application of membranes. The result from the histological examination of biopsy specimens revealed that GTR treatment may result in complete new attachment at surgically produced "through and through" furcation involvements in dogs. The study, however, also revealed that the size of the furcation defect as well as the shape of the surrounding alveolar bone were factors that determined the outcome of this kind of treatment. The treatment failures were consistently associated with flap recession during healing which resulted in the exposure of the furcation defect.