Effect of enamel matrix proteins (Emdogain®) on healing after re-implantation of "periodontally compromised" roots -: An experimental study in the dog

Objective: The present experiment was performed to assess whether Emdogain(R) applied on the root surface of extracted teeth or teeth previously exposed to root planning can protect the tooth from ankylosis following re-implantation. Material and Methods: The experiment included two groups of dogs, including five animals each. The root canals of all mandibular third premolars (P-3(3)) were reamed and filled with gutta-percha. A crestal incision was placed from the area of the second to the fourth premolar. Buccal and lingual full thickness flaps were elevated. With the use of a fissure bur, the crown and furcation area of P-3(3) were severed in an apicocoronal cut. The distal and mesial tooth segments were luxated with an elevator and extracted with forceps. Group A: The mesial and distal segments Of P-3(3) were air dried on a glass surface for 60 min. The roots from the right side were conditioned and exposed to Emdogain(R) application. The roots from the left side received the same treatment with the exception of Emdogain(R) application. The mesial and distal tooth segments were re-implanted and the crown portions were severed with a horizontal cut and removed. The buccal and lingual flaps were mobilized and sutured to obtain complete coverage of the submerged roots. Group B: A notch was prepared in each root, 4-5 mm apical of the cemento-enamel junction. The area of the root that was located coronal to the notch was scaled and planned. The roots in the right side of the mandible were treated with Emdogain(R), while the roots in the left side served as controls. After 6 months of healing, the dogs were killed and blocks containing one root with surrounding tissues were harvested, and prepared for histological examination, which also included morphometric assessments. Thus, the proportions of the roots that exhibited signs of (i) replacement (ii) inflammatory and (iii) surface resorption were calculated. Results and Conclusion: It was demonstrated that healing of a re-implanted root that had been extracted and deprived of vital cementoblasts was characterized by processes that included root resorption, ankylosis and new attachment formation. It was also demonstrated that Emdogain(R) treatment, i.e. conditioning with EDTA and placement of enamel matrix proteins on the detached root surface, failed to interfere with the healing process.