EFFECTS OF CALCIUM INTAKE ON ALVEOLAR BONE

钙摄入量对牙槽骨的影响

• 批准号: 6145863
• 负责人: ANNE-MARIE BOLLEN
• 金额: --
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-08-01 至 2000-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6145863
• 关键词: animal old age; bone density; dental alveolus; dental radiography; dietary calcium; laboratory rat; nutrition related tag; osteoporosis; pathologic process; periodontitis

The benefits of sufficient levels of calcium intake in the prevention of osteoporotic fractures are well recognized. Since alveolar bone is influenced in the same manner as other bones, dietary calcium levels are assumed to also affect its density. It has been suggested that increased alveolar bone density may increased bone loss during periodontitis. The primary goal of this study is to evaluate the effects of calcium intake on alveolar bone, and its capacity to decrease periodontitis-induced bone loss at old age, in a rat model. Rats were chosen due to their previous extensive use in bone and periodontitis studies, and their relative short life span which allows evaluation of the effects of calcium intake at old age, when its benefits are of most value. Two calcium intake levels will be used: low, and high. The following aims will be addressed: 1. Test the difference in alveolar bone density at old age (20 months) between the two calcium intake groups. 2. Test the difference in periodontitis-induced alveolar bone loss at old age between the two groups. 3. Describe how bone density measures of cranial and post-cranial change during the study period in the two animal groups. Animals will be randomly assigned to one of the two calcium intake groups at age 1 month, and followed until the age of 20 months. At that time, some of the animals will be euthanized for invasive bone measurements for Aim 1. Periodontitis will be i induced in the remainder of the animals who will be followed until the age of 23 months. Non-invasive longitudinal data collected at the age of 1,3,8,13,20 and 23 months will include bone density measurements using dual x-ray radiography (cranial and non-cranial bones), as well as intra-oral radiographs of the molars (alveolar bone). The primary outcome variable for Aim 1 will be alveolar bone density, and for Aim 2 alveolar bone loss. Alveolar bone density will be measured on defleshed jaws using dual x-ray absorptiometry and pixel intensity on oral radiographs. Alveolar bone loss will be measured on the buccal of the molars using morphometry on defleshed jaws, and radiographically on intraoral radiographs. In addition, static and dynamic parameters of bone metabolism will be measured using histomorphometry. Power calculations indicate that 21 animals per group will be needed to detect a minimum of 5% in alveolar bone density (Aim 1). A total of 24 animals will be needed to detect a minimum of 10% difference in alveolar bone loss (Aim 2) between any of the two calcium intake groups with a power of 80% at a 0.05 significance level. To test the effect of calcium intake with equal precision in male and female rats, a equal sample size will be required for both genders. These calculations include an estimated 20% mortality rte in these elderly rats. This study may indicate the benefits of dietary calcium intake on dental/orofacial health. This additional benefit may help to promoter this preventive therapy.

充分摄入钙对预防骨质疏松性骨折的益处是公认的。由于牙槽骨受到影响的方式与其他骨骼相同，因此膳食钙水平也会影响其密度。有研究表明，牙周炎时牙槽骨密度增加可能会增加骨丢失。本研究的主要目的是在大鼠模型中评估钙摄入对牙槽骨的影响，以及其减少老年牙周炎引起的骨丢失的能力。选择大鼠是因为它们先前在骨骼和牙周炎研究中的广泛使用，以及它们相对较短的寿命，这使得可以评估老年时钙摄入的影响，此时钙的益处最有价值。将使用两种钙摄入水平：低和高。以下目标将被解决：1。测试两个钙摄入组之间老年（20个月）时牙槽骨密度的差异。2.比较两组老年人牙周炎引起牙槽骨丢失的差异。3.描述研究期间两个动物组的骨密度如何测量颅骨和颅骨后变化。在1月龄时将动物随机分配至两个钙摄入组之一，并随访至20月龄。此时，将对部分动物实施安乐死，以进行目标1的侵入性骨测量。将在其余动物中诱发牙周炎，并对其进行跟踪直至23个月大。在1、3、8、13、20和23个月龄时收集的非侵入性纵向数据将包括使用双X射线摄影（颅骨和非颅骨）的骨密度测量，以及磨牙（牙槽骨）的口内X射线照片。目标1的主要结局变量是牙槽骨密度，目标2的主要结局变量是牙槽骨丢失。将使用双X线吸收测定法和口腔X线片像素强度测量去死皮颌骨的牙槽骨密度。牙槽骨丢失将在磨牙的颊侧使用形态测量法测量去牙颌，并在口内X线片上进行X线检查。此外，将使用组织形态计量学测量骨代谢的静态和动态参数。功效计算表明，每组需要21只动物才能检测到至少5%的牙槽骨密度（目标1）。总共需要24只动物来检测两个钙摄入组之间的牙槽骨丢失（目标2）的至少10%差异，功效为80%，显著性水平为0.05。为了在雄性和雌性大鼠中以相同的精度检测钙摄入量的影响，两种性别需要相同的样本量。这些计算包括这些老年大鼠中估计的20%死亡率。这项研究可能表明膳食钙摄入量对牙齿/口面健康的好处。这种额外的益处可能有助于促进这种预防性治疗。