MTA修复犬牙髓室底穿孔的组织学评价

目的 用MTA、Dycal、GIC即时修复不同大小髓室底穿孔，从组织学角度评价三种材料对牙周组织的炎症反应和硬组织形成的影响。方法 选择3条成年杂种犬的42颗后牙，用随机法先将一侧牙分为小穿孔组，另一侧牙分为大穿孔组；每侧再分为三个亚组，分别用MTA、Dycal、GIC修复。4个月后处死动物，标本经处理，光学显微镜下观察材料下方牙周组织的炎症细胞及其程度、上皮增生以及硬组织形成情况。结果 MTA组的14例中5例无炎症反应，其余9例仅有轻度至中度的炎症反应，4例有牙骨质形成，周围可见成牙骨质细胞；Dycal组材料下方均引起牙周组织中度或重度的炎症反应，2例小穿孔处有不规则的钙化物沉积，同时伴有大量炎症细胞，上皮增生多见(6／14)；GIC组除1例大穿孔标本有少量散在的炎症细胞及纤维组织包绕，其余标本均可见中度或重度的炎症反应，有的伴有上皮增生(4／14)。上皮增生与穿孔大小有一定关系。结论 MTA用于即时修复犬牙髓室底穿孔，能诱导硬组织形成，对组织的刺激小，效果优于GIC和Dycal。

Histological Evaluation on Repair of Furcation Perforation in Dogs Using Mineral Trioxide Aggregate

Objective To investigate histological response to immediate repair of different sizes of furcation perforation using MTA,Dycal and GIC.Methods 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 sacrificed4months later,and the specimens processed and examined under the light microscope.Inflammation,epithelial proliferation,and formation of hard tissue over the material were evaluated.Results 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 inflammtory cells around the material.Four cases presented epithelial proliferation.There was some relation between epithelial proliferation and size of perforation.Conclusion 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.