Efficacy of enamel matrix proteins on apical periodontal regeneration after experimental apicoectomy in dogs

Adult dogs have a complex apical delta structure in all root apexes of teeth. This complex structure may affect the formation of apical lesions in the teeth such as apical abscesses. The purpose of this study was to evaluate the efficacy of enamel matrix protein (EMP) which was used for periodontal regeneration therapy after an experimental apicoectomy for an assumed apical lesions of the teeth in dogs. The maxillar canine roots and maxillar fourth premolar buccal mesial roots in five beagles were experimentally apicoectomized under general inhalation anesthesia. After the root apex was exposed and excised, EMP was applied on the surface of the exposed dentin. After 12 weeks, dogs were euthanized, and, the experimental teeth together with the surrounding soft and hard periodontal tissues were collected for histological evaluation under a light microscope. In the EMP group, the size of the defect where the root apex was removed was smaller than that of the control group. New cementum was dominantly achieved in the EMP group compared to the control group. Furthermore, new collagen fibers that bridged area between the new cementum and new alveolar bone were detected only in the EMP group. The present results demonstrated marked apical periodontal regeneration after apicoectomy in the EMP group. These results, therefore, suggest that the application of EMP can effectively induce the regeneration of periodontal structures in apicoectomized dogs.