Purpose: to examine histologically the tissue response to experimentally induced furcal perforations, repaired with amalgam or MTA either immediately or after salivary contamination
N= 28 mandibular premolars in seven dogs
Materials and Methods:
•30 perforations were made after the dogs were anesthetized.
•Root canals were cleaned, shaped and obturated with gutta percha and sealer.
•A trephine bur was used at low speed to make a perforation.
•In half the teeth, the perforation was filled immediately with amalgam or MTA after control of hemorrhage by saline and cotton pellets.
•In the rest of the teeth, the perforations were left open to salivary contamination for 6 weeks to allow for formation of inflammatory lesion in the furcation, then cleaned by sodium hypochlorite irrigation, dried and filled with amalgam or MTA.
•Access cavities were filled with MTA and the animals were sacrificed 4 months later.
•Sectioned jaws prepared for histologic examination with H&E, Masson’s trichrome, and by Brenn method
•Sections examined by 2 observers.
•MTA group, in five out of six teeth no inflammation and formation of cementum occurred.
•Amalgam group, always associated with inflammation that was often moderate to severe.
•3/7 filled with MTA were free from inflammation.
•Teeth repaired with amalgam were always associated with inflammation that was severe.
Clinical significance: MTA has a favorable response when used for immediate perforation repair