Rodrigues Lidiany Karla Azevedo, Cury Jaime Aparecido, Nobre dos Santos Marinês
Department of Restorative Dentistry, Faculty of Dentistry, Federal University of Ceará, Fortaleza, Ceará, Brazil.
J Oral Sci. 2004 Dec;46(4):215-20. doi: 10.2334/josnusd.46.215.
Given the importance of sterilizing human teeth before using them in research, the effects of a 25 kGy dose of gamma radiation on the mechanical properties of enamel and its resistance to demineralization were evaluated. Thirty human teeth were sectioned longitudinally, and while one half of each tooth was irradiated, the other half was kept as a control. Abraded and unabraded enamel slabs were obtained from these halves. The surface microhardness (SMH) of abraded slabs of irradiated and non-irradiated enamel was determined to evaluate the effect of radiation on enamel structure. Further, both abraded and unabraded slabs, either irradiated or non-irradiated, were submitted to a pH-cycling model to evaluate enamel resistance to demineralization, which was quantified by mineral loss (deltaZ) using cross-sectional microhardness. The data for SMH and deltaZ were statistically analyzed by t-test and ANOVA, respectively. The difference in enamel SMH between slabs from irradiated teeth and non-irradiated teeth was not statistically significant (P > 0.05). The abraded enamel slabs showed higher values of deltaZ than unabraded enamel slabs (P < 0.05), but the irradiation effect was not statistically significant (P > 0.05). The results suggest that the medical gamma radiation dose of 25 kGy does not affect either enamel hardness or its resistance to demineralization.
鉴于在研究中使用人类牙齿之前进行消毒的重要性，评估了25千戈瑞剂量的伽马辐射对牙釉质力学性能及其抗脱矿能力的影响。将30颗人类牙齿纵向切开，每颗牙齿的一半进行辐照，另一半作为对照。从这些牙齿的两半获取了磨损和未磨损的牙釉质板。测定辐照和未辐照牙釉质磨损板的表面显微硬度（SMH），以评估辐射对牙釉质结构的影响。此外，将辐照或未辐照的磨损和未磨损板都置于pH循环模型中，以评估牙釉质的抗脱矿能力，通过使用横截面显微硬度的矿物质损失（deltaZ）进行量化。分别通过t检验和方差分析对SMH和deltaZ的数据进行统计分析。辐照牙齿和未辐照牙齿的牙釉质SMH差异无统计学意义（P>0.05）。磨损的牙釉质板显示出比未磨损牙釉质板更高的deltaZ值（P<0.05），但辐照效果无统计学意义（P>0.05）。结果表明，25千戈瑞的医用伽马辐射剂量既不影响牙釉质硬度，也不影响其抗脱矿能力。
