Balto K, Müller R, Carrington D C, Dobeck J, Stashenko P
Department of Cytokine Biology, Forsyth Institute, Harvard School of Dental Medicine, Boston, MA 02115, USA.
J Dent Res. 2000 Jan;79(1):35-40. doi: 10.1177/00220345000790010401.
Bacterial infections of the dental pulp result in tissue destruction and periapical bone resorption. The availability of genetically engineered mouse strains is a major advantage in the use of this model system for studies of periapical pathogenesis. The main limitation of the mouse model is its small size, and the necessity for laborious histologic analyses to quantify periapical bone destruction. In the present study, we evaluated the use of a new technology, high-resolution micro-computed tomography (micro-CT), for the rapid and non-invasive quantification of periapical bone destruction. Periapical lesions were induced in the lower first molars of mice by exposing the pulp to the oral environment. Mandibles were harvested on day 21 after pulp exposure, and were subjected to micro-CT analysis, with 17-microm-thick radiographic sections. Samples were then decalcified, embedded, and sectioned for histology. The cross-sectional area of periapical lesions was determined by image analysis of corresponding micro-CT and histologic sections. The results showed a highly significant correlation between micro-CT and histology (p < 0.0001), with mean differences of 4. 1% (range, 0.9 to 7.2%) between the two methods. The mean error associated with image analysis was 4.9% for images obtained by both micro-CT and histology. The variability of replicate (n = 5) independent micro-CT determinations was 3.4%, less than that associated with the image analysis error. These results demonstrate that micro-CT imaging is a rapid, reproducible, and non-invasive method, that gives results that are closely comparable with those obtained by histology. Micro-CT appears to have utility for the accurate quantification of changes in bone architecture in small biological specimens.
牙髓的细菌感染会导致组织破坏和根尖周骨吸收。基因工程小鼠品系的可用性是将该模型系统用于根尖周发病机制研究的一个主要优势。小鼠模型的主要局限性在于其体型小，且需要费力地进行组织学分析以量化根尖周骨破坏。在本研究中，我们评估了一种新技术——高分辨率微型计算机断层扫描（微型CT）用于快速、非侵入性量化根尖周骨破坏的情况。通过将牙髓暴露于口腔环境，在小鼠的下颌第一磨牙中诱导根尖周病变。在牙髓暴露后第21天采集下颌骨，并进行微型CT分析，获得17微米厚的射线照片切片。然后将样本脱钙、包埋并切片进行组织学检查。通过对相应的微型CT和组织学切片进行图像分析来确定根尖周病变的横截面积。结果显示微型CT与组织学之间具有高度显著的相关性（p < 0.0001），两种方法之间的平均差异为4.1%（范围为0.9%至7.2%）。与图像分析相关的平均误差在微型CT和组织学获得的图像中均为4.9%。重复（n = 5）独立微型CT测定的变异性为3.4%，小于与图像分析误差相关的变异性。这些结果表明，微型CT成像快速、可重复且非侵入性，其结果与组织学结果高度可比。微型CT似乎可用于准确量化小型生物标本中骨结构的变化。
