Periodontal regeneration in intrabony defects after application of enamel matrix proteins with guided tissue regeneration: An experimental study in dogs

The aim of this study was to evaluate the effects of enamel matrix proteins (EMP) at the early stage of wound healing in the periodontal tissues by a combination treatment with guided tissue regeneration (GTR). Intrabony defects were produced surgically at the distal aspects of both mandibles in six beagle dogs. At 12 weeks following the surgery, the defects were exposed using a full thickness mucoperiosteal flap procedure. Subsequently, the defects were treated by the following treatments: a control group treated with GTR alone, and an experimental group treated with a combination of GTR and EMP. After one, two, four and eight weeks of the treatment, the animals were sacrificed, and sections of the tissue were stained and evaluated microscopically. After one and two weeks, the proliferating cell nuclear antigen (PCNA)-positive cell ratios of the experimental group were significantly greater than that of the control group. After 2 and 4 weeks, new bone and new cementum formation in the experimental group were significantly greater than those in the control group (P < 0.05). However, after 8 weeks, no statistical difference was found between the two groups in new bone or cementum formation. The study results suggest that a maturation of periodontal ligament cells might contribute, during the early stage of periodontal healing, to stimulate a proliferation of periodontal ligament cells.