Federal University of Uberlândia, Dept. of Operative Dentistry and Dental Materials, Brazil.
J Dent Res. 2010 Feb;89(2):159-64. doi: 10.1177/0022034509351251. Epub 2009 Dec 30.
The effect of gamma irradiation therapy on the ultimate tensile strength (UTS) of enamel and dentin in relation to prism orientation, dentin tubule orientation, and location is unknown. It was hypothesized that tubule and prism orientation, location, and irradiation have an effect on the UTS of dental structures. Forty human third molars were used, half of which were subjected to 60 Gy of gamma irradiation, in daily increments of 2 Gy. The specimens were evaluated by microtensile testing. Results showed that irradiation treatment significantly decreased the UTS of coronal and radicular dentin and of enamel, regardless of tubule or prism orientation. With or without irradiation, enamel was significantly stronger when tested parallel to its prismatic orientation. Coronal and radicular dentin of non-irradiated specimens presented significantly higher UTS when tested perpendicularly to tubule orientation. However, when the teeth were irradiated, the influence of tubule orientation disappeared, demonstrating that irradiation is more harmful to organic components.
伽马射线照射治疗对牙釉质和牙本质极限拉伸强度（UTS）的影响与棱柱体方向、牙本质小管方向和位置有关，但目前尚不清楚。本研究假设小管和棱柱体方向、位置和照射对牙结构的 UTS 有影响。本研究使用了 40 颗人第三磨牙，其中一半接受了 60Gy 的伽马射线照射，每天递增 2Gy。通过微拉伸测试对标本进行了评估。结果表明，无论小管还是棱柱体方向如何，辐照处理都会显著降低牙冠和牙根牙本质以及牙釉质的 UTS。无论是否辐照，当平行于其棱柱体方向测试时，釉质的强度明显更高。未辐照标本的牙本质冠部和根部当垂直于小管方向测试时，呈现出更高的 UTS。然而，当牙齿被辐照时，小管方向的影响消失了，这表明辐照对有机成分的危害更大。
