Effect of diabetes mellitus on total amount of bone resorption in the tissues under denture base bearing masticatory pressure

糖尿病对义齿支持组织中骨动力学的影响尚未得到足够的研究。为探讨糖尿病对义齿基托承受咀嚼压力组织骨吸收的影响，选用Wistar系糖尿病雄性大鼠250只（n= 50 × 5组）。在22周龄时，将DALDENT基底应用于硬腭的磨牙区域。在加载组中，托座设计为分别向腭施加1.0、10.0或20.0 kPa的咀嚼压力。覆盖组设计义齿基托与腭部接触，不施加任何机械压力。不戴义齿组不接受任何治疗。每隔3或4天进行腭和活动义齿基托的清洁。实验组和对照组各取5只大鼠，每隔1周，于义齿戴入后切取腭部组织块。标本用Villanueva骨染色剂染色，包埋在甲基丙烯酸甲酯中，正面研磨至50μm厚。用二维图形分析系统计算破骨细胞表面和侵蚀表面。骨吸收量按（A）-（B）计算：（A）覆盖组戴入义齿前12周内形成的骨组织，（B）各实验阶段各骨吸收组骨吸收结束后的剩余骨组织，10.0和20.0 kPa组分别观察到戴入义齿后6周的骨吸收。骨吸收总量10.0kPa组为189±38μm，20.0kPa组为266±27μm。与正常大鼠在相同条件下的实验结果比较，表明糖尿病延长了骨吸收的时间，增加了骨吸收的总量。

The effect of diabetes mellitus on-bone dynamics in denture supporting tissue has not been investigated enough. The purpose of this study was to investigate the effect of diabetes mellitus on bone resorption in the tissues under denture base bearing masticatory pressure by using bone histomorphometry.Two-hundred and fifty streptozotocin-induced diabetic male rats (n=50X5 groups) of Wistar strain were used in this study. Denture base was applied to the molar region of the hard palate at 22 weeks of age. In loaded groups, the denture base were designed to load a masticatory pressure of 1.0, 10.0 or 20.0 kPa to the palate, respectively. In covering group, the denture base was designed to contact with the palate without any mechanical pressure. The non-denture-wearing group received no intentional treatment. The cleansing of the palate and removable denture base was carried out at 3 or 4 day intervals. Palatal tissue block was excised from 5 rats of each experimental group after the denture insertion at one week interval. The specimens were stained with Villanueva bone stain, embedded in methyl-methacrylate, and ground frontally to 50μm thickness. Eroded surface and osteoclast surface were calculated by using two-dimensional graphic analyzing system. Amount of bone resorption was calculated as (A)-(B) ; (A) Formed bone tissue during 12 weeks prior to the denture insertion in covering group, (B) Remained bone tissue after the end of bone resorption in each bone resorbed group at each experimental period.Bone resorption was observed in 10.0 and 20.0 kPa groups until 6 weeks after the denture insertion, respectively. Total amount of bone resorption was 189±38μm in 10.0 kPa group and 266±27μm in 20.0 kPa group. Comparing these results with results in normal rats in same condition as this study, it is showed that diabetes mellitus prolongs the period of bone resorption and increases total amount of bone resorption.