摘要
There is an increase in the mineral content of human dentin with aging. Due to the consequent changes in the mineral to the collagen ratio, this process may influence the degree of hydrogen bonding that occurs with the loss of water and the extent of shrinkage as a result of dehydration. Thus, the objective of this investigation is to quantify the differences in the dehydration shrinkage of human dentin with patient age. Specimens of coronal dentin are prepared from the molars of young （23 ~〈 age 34） and old （52 ~ age ~〈 62） patients, and then maintained in storage solutions of water or hanks balanced salt solutions （HBSS）. Dimensional changes of the dentin specimens occurring over periods of free convection are evaluated by using the microscopic digital image correlation （DIC）. The results distinguish that the shrinkage of the young dentin is significantly larger than that of the old dentin, regardless of the orientation and period of the storage. The strains parallel to the tubules increase with proximity to the dentin enamel junction （DE J）, whereas the shrinkage largest in the deep dentin （i.e., near the pulp）. increases from the pulp to the DE J, and is the strains in the transverse direction axe the The degree of anisotropy in the shrinkage largest in the young dentin.
There is an increase in the mineral content of human dentin with aging. Due to the consequent changes in the mineral to the collagen ratio, this process may influence the degree of hydrogen bonding that occurs with the loss of water and the extent of shrinkage as a result of dehydration. Thus, the objective of this investigation is to quantify the differences in the dehydration shrinkage of human dentin with patient age. Specimens of coronal dentin are prepared from the molars of young （23 ~〈 age 34） and old （52 ~ age ~〈 62） patients, and then maintained in storage solutions of water or hanks balanced salt solutions （HBSS）. Dimensional changes of the dentin specimens occurring over periods of free convection are evaluated by using the microscopic digital image correlation （DIC）. The results distinguish that the shrinkage of the young dentin is significantly larger than that of the old dentin, regardless of the orientation and period of the storage. The strains parallel to the tubules increase with proximity to the dentin enamel junction （DE J）, whereas the shrinkage largest in the deep dentin （i.e., near the pulp）. increases from the pulp to the DE J, and is the strains in the transverse direction axe the The degree of anisotropy in the shrinkage largest in the young dentin.
基金
supported by the National Natural Science Foundation of China (No. 11172161)
the Shanghai Leading Academic Discipline Project (No. S30106)
the Innovation Program of Shanghai Municipal Education Commission (No. 12ZZ092)
the State Key Laboratory of Oral Diseases in Sichuan University (No. SKLODSCU2009KF03)
the Science and Technology Commission of Shanghai Municipality (Nos. 10410701900,11195820900,and 10ZR1423400)
the National Institute of Dental and Craniofacial Research (No. R01-DE016904)
