Enamel matrix derivative and guided tissue regeneration in the treatment of dehiscence-type defects: a histomorphometric study in dogs

BACKGROUND: The goal of this investigation was to histologically and histometrically evaluate the healing process of dehiscence-type defects treated by enamel matrix derivative (EMD) and/or guided tissue regeneration (GTR). METHODS: Seven mongrel dogs were used. Buccal osseous dehiscences were surgically created on the mesial roots of the mandibular third and fourth premolars. The defects were exposed to plaque accumulation for 3 months. After this period, the defects were randomly assigned to one of the treatments: open flap debridement (OFD), enamel matrix derivative (EMD), GTR with bioabsorbable membrane (GTR), and the combination of both procedures (EMD + GTR). After 4 months of healing, the dogs were sacrificed and the blocks were processed. The histometric parameters evaluated included gingival recession, epithelial length, connective tissue adaptation, new cementum, and new bone. RESULTS: A superior length of new cementum was observed in the sites treated by EMD (3.7 mm) and EMD + GTR (3.8 mm) in comparison with OFD (2.4 mm) (P < 0.05). No statistically significant differences were found in the remaining histometric parameters. CONCLUSIONS: Within the limits of this study, it can be concluded that EMD alone or in combination with GTR barriers may effectively promote new cementum formation. The combination of both therapies may not provide additional benefits.