Evaluation of healing with use of an internal matrix to repair furcation perforations

The purpose of this study was to evaluate healing responses following repair of furcation perforations, with and without an internal matrix. Two matrix materials, HAPSET (65% non-resorbable hydroxyapatite and 35% plaster of paris) and hydroxyapatite were compared. Four adult female baboons (Papio anubis) served as experimental models. Furcation perforations were made in the molar and premolar teeth, which were then randomly assigned to one of the five groups, according to the method of perforation repair: 1 Experimental group 1 (16 teeth): The matrix material was HAPSET and the sealing material, amalgam. 2 Experimental group 2 (16 teeth): The matrix material was hydroxyapatite and the sealing material, amalgam. 3 Experimental group 3 (16 teeth): No matrix was placed. The sealing material was amalgam. 4 Positive control group (16 teeth): The perforation was not sealed. 5 Negative control group (16 teeth): No perforation was made. The animals were sacrificed at 1 week and 1, 3 and 7 months. Specimens were prepared for examination with light microscopy. The data revealed that when amalgam was used alone without a matrix, there was marked extrusion of the material into the underlying bone with an associated severe inflammatory response, which continued throughout the observational period. When an internal matrix was used, there was an initial acute inflammatory response that diminished with time such that at 7 months, 75% of these specimens were free of inflammation. There was no difference in the tissue response to the different matrix materials. HAPSET and hydroxyapatite underwent connective tissue encapsulation in the early stages followed by new bone deposition in direct contact with the materials. Within this animal model healing responses are better when an internal matrix, whether HAPSET or hydroxyapatite, is used in the repair of furcation perforations.