Effect of aging on deformation behavior of dentin in small area.

在本研究中，我们试图评估老化对小面积牙本质变形行为的影响。对激光散斑应变测量方法应用于牙本质标本的可行性进行了研究，认为该方法适用于牙本质小标本的应变测量。将牙本质材料浸入根管内药物中，分别置于5ﾟC或55ﾟC水中保存，并进行热循环实验，评价牙本质老化效应的模拟过程。加入某种根管内药物后，牙本质抗拉强度显著增加，但浸入根管内药物对牙本质性能的影响不同。在5ﾟC和55ﾟC之间放置2周的水对牙本质的抗拉强度没有显着影响，但热循环2周后获得的威布尔模数有下降的趋势，因此，更长的水浸泡时间对牙本质的影响可能与老化相似。牙本质的衰老机制尚需进一步研究。

In this research, we tried to evaluated effects of aging on deformation behavior of dentin in small area. A laser speckle strain measurement was examined for possibility of dentin specimen application ; this method was considered to be suitable for strain measurement of small dentin specimen. Simulation procedure of aging effect on dentin were evaluated after immersion into intercanal medicaments and storage in 5ﾟC or 55ﾟC water and thermocycling test. Dentin tensile strength after a certain intercanal medicament significantly increased, however immersion into-intercanal medicaments was not similar effects of aging on dentin properties. Water storage for two week between 5ﾟC and 55ﾟC did not significantly effect on dentin tensile strength ; however obtained Weibull modulus after two week thermocycling had a tendency to decreased ; therefore longer water immersion might be similar effect of aging on dentin. Further investigation is necessary to clarify the aging mechanism of dentin.