Updike Sophia Xiang, Nowzari Hessam
Department of Orthodontics, School of Dentistry, University of Southern California, Los Angeles, CA 90089-064, USA.
J Periodontal Res. 2008 Dec;43(6):658-64. doi: 10.1111/j.1600-0765.2007.01056.x. Epub 2008 Jun 24.
The aim was to evaluate fractal analysis as a tool to quantitatively measure the impact of periodontal disease on surrounding bone. The diagnosis of periodontitis is based on information obtained from clinical and radiographic examinations. The current standard use of dental radiographs is visual inspection, often with no quantitative analysis. Fractal analysis can be used to examine trabecular bone patterns among periodontal patients.
Patients (n = 108) from the University of Southern California School of Dentistry were classified into three groups: healthy, moderate and severe periodontitis. A region of interest was selected from periapical radiographs. Image processing was applied to correct for lighting irregularity, and the box-counting method was used to calculate a fractal dimension. ANOVA and ANCOVA were used to measure fractal dimension differences between all groups.
According to the statistical tests, significant differences in average fractal dimensions were measured between healthy and moderate periodontitis groups (p < 0.01) and between healthy and severe periodontitis groups (p < 0.001). Higher fractal dimensions were measured in healthy periodontal patients.
Fractal analysis evidenced significant differences between patients affected and not affected by periodontitis. The box-counting method quantitatively describes the severity of bone disease and can be used to improve current diagnostic techniques.
本研究旨在评估分形分析作为一种定量测量牙周疾病对周围骨组织影响的工具。牙周炎的诊断基于临床和影像学检查所获得的信息。目前牙科X光片的标准用法是目视检查,通常不进行定量分析。分形分析可用于检查牙周病患者的骨小梁模式。
南加州大学牙科学院的患者(n = 108)被分为三组:健康组、中度牙周炎组和重度牙周炎组。从根尖X光片中选取感兴趣区域。应用图像处理来校正光照不均,并采用盒计数法计算分形维数。方差分析(ANOVA)和协方差分析(ANCOVA)用于测量所有组之间的分形维数差异。
根据统计检验,健康组与中度牙周炎组之间(p < 0.01)以及健康组与重度牙周炎组之间(p < 0.001)的平均分形维数存在显著差异。健康牙周病患者的分形维数更高。
分形分析证明了牙周炎患者与未患牙周炎患者之间存在显著差异。盒计数法可定量描述骨疾病的严重程度,并可用于改进当前的诊断技术。