[Histological evaluation on repair of furcation perforation in dogs using mineral trioxide aggregate]

To investigate histological response to immediate repair of different sizes of furcation perforation using MTA, Dycal and GIC.

Forty-two posterior teeth in three adult beagle dogs were randomly divided into two groups, small perforation group and large perforation group. Each group was then divided into three sub-groups which were repaired with MTA, Dycal and GIC respectively. The dogs were sacrificed 4 months later, and the specimens processed and examined under the light microscope. Inflammation, epithelial proliferation, and formation of hard tissue over the material were evaluated.

In teeth repaired with MTA, five cases were free of inflammation, and the other nine cases were associated with slight or moderate inflammation. There was formation of cementum with cementoblast cells around it in four cases. In the group of Dycal, all specimens had moderate or severe inflammation. The deposition of irregular calcified tissues as well as a large quantity of inflamed cells were found in two cases of small perforation. Six cases presented epithelial proliferation. In the group of GIC, moderate or severe inflammation was seen in all cases except for one case of large perforation with fibrous tissues and sparse inflammatory cells around the material. Four cases presented epithelial proliferation. There was some relation between epithelial proliferation and size of perforation.

MTA is superior to GIC and Dycal for immediate repairing furcation perforation in dogs owing to its less irritation to surrounding tissues and its ability to induce the formation of hard tissues.