牙体牙髓治疗材料对牙本质抗折性能的影响

目的　探究Biodentine和MTA对牙本质抗折性能的影响。 方法　选40颗中华田园犬尖牙，截冠、去除牙骨质并截去根尖，随机等分为5组。分别在根管内充填不同药物，3个月后行力学测试，得到标本3点弯曲强度和弯曲模量。 结果　各组标本3点弯曲强度分别: (154.77±16.51) MPa；(125.00±15.72) MPa； (140.81±11.99) MPa；(139.26±16.09) MPa； ( 120.17±14.21) MPa，单因素方差分析，F=6.74（P<0.05)。各组标本弯曲模量分别为:(19.50±1.03) GPa；(9.62±1.34) GPa；(17.08±1.14) GPa；(15.73±2.14) GPa；(7.63±1.11) GPa；单因素方差分析，F=102.94（P<0.05）。Biodentine和MTA对牙本质抗折性能的影响无统计学差异；与阳性对照组相比，Biodentine和MTA并不能提高牙本质抗折性能；与空白对照组和Vitapex相比，Biodentine和MTA能明显增加牙本质抗折性能。 结论　作为新兴生物性牙本质替代材料，与传统硅酸钙盐材料MTA相比，Biodentine在提高无髓牙牙本质抗折性能方面，并不具备明显优势。

Effect of materials in the treatment of endodontic diseases on the dentin’s fracture resistance

Objective　To investigate the effect of Biodentine and MTA on the dentin’s fracture resistance.　Methods　40 fresh extracted Chinese rural dogs’ canines were collected and randomly divided into 5 groups. The crowns and the cementum of the teeth were dissected. Each tooth was prepared with unity sample at the length of about 25 mm. Five groups’ samples were filled with different medicines. The three-point flexural strength and flexural modulus of the experimental specimens were determined by applying a vertical splitting load through a specially shaped steel rod. The maximum load value of root fracture was tested after three months. Results The average three-point flexural strength of the five groups was sequentially: (154.77±16.51) MPa; (125.00±15.72 ) MPa; (140.81±11.99) MPa; (139.26±16.09) MPa; (120.17±14.21) MPa. The average three-point flexural strength of the five groups were in order: (19.50±1.03)GPa ; (9.62±1.34) GPa ; (17.08±1.14)GPa ; (15.73±2.14) GPa ; (15.73±2.14) GPa; (7.63±1.11) GPa. The data were analyzed by one way ANOVA and LSD method (P<0.05). The risk of pulpless root fracture may increase obviously as time goes by. The differences of the effect of Biodentine and MTA on the dentin’s fracture resistance remains no statistically significant. Compared with the positive control group, MTA and Biodentine did not increase or restore the fracture resistance of dentin. But compared with the negative control group and Vitapex, Biodentine and MTA could significantly increase the fracture resistance of dentin.　Conclusion　As a new biological dentin substitute materials, compared with the traditional calcium silicate material-MTA, Biodentine did not have the obvious advantage in improving the flexural properties of dentine.