AIM This single-centre retrospective case-control study evaluated the fractal dimension (FD) changes in periapical lesion area using a fractal analysis in healthy individuals and type 2 diabetes mellitus (DM) patients following root canal treatment. METHODOLOGY The study data consisted of two groups: the DM group which contained a total of 46 mandibular molar teeth in 37 patients with no systemic disease other than type 2 DM, and the control group which contained a total of 52 mandibular molar teeth in 41 patients without any systemic disease. Periapical radiographs were obtained prior to root canal treatment and 1-year post-treatment. Fractal analysis was performed by selecting a region of interest (ROI) on the periapical radiographs. For both groups, the FD changes in lesion area were calculated and compared. In addition, periapical status was evaluated using the periapical index (PAI) scores on periapical radiographs for both groups. Data were analysed using dependent sample t-test, independent sample t-test, Wilcoxon signed rank test, and Mann-Whitney U-test. RESULTS In both groups, FD values were increased significantly 1-year post-treatment as compared with those prior to treatment (p<0.05). The time-dependent increase in FD was significantly greater in the control group (p<0.05). Time-dependent increases in FD did not differ between genders (p> 0.05). There was a significant decrease in PAI scores in both type 2 DM and control groups depending on time (p<0.05). No significant difference was found between the groups in terms of time-related decreasing in PAI scores (p>0.05). CONCLUSION An increase in the fractal dimension of the periapical lesion area was observed 1-year after root canal treatment. Diabetes Mellitus had a negative effect on fractal dimension increase.

中文翻译：

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2型糖尿病对根管治疗后牙齿根尖周病变的分形维数变化的影响：分形分析研究。

目的该单中心回顾性病例对照研究通过对健康个体和根管治疗后的2型糖尿病（DM）患者进行分形分析，评估了根尖周病变区域的分形维数（FD）变化。方法：研究数据包括两组：DM组共包含46例下颌磨牙，除2型DM以外，无系统性疾病；而对照组共包含52例下颌磨牙。没有任何全身性疾病。在根管治疗之前和治疗后1年获得根尖X光片。通过在根尖周片上选择感兴趣区域（ROI）来进行分形分析。两组均计算并比较了病变区域的FD变化。此外，使用两组的根尖周片上的根尖指数（PAI）评分评估根尖状态。使用相关样本t检验，独立样本t检验，Wilcoxon符号秩检验和Mann-Whitney U检验分析数据。结果在两组中，治疗后1年的FD值均较治疗前显着增加（p <0.05）。FD的时间依赖性增加在对照组中明显更大（p <0.05）。FD的时间依赖性增加在性别之间没有差异（p> 0.05）。在2型DM和对照组中，PAI评分均显着下降，这取决于时间（p <0.05）。在时间相关的PAI分数降低方面，两组之间没有发现显着差异（p> 0.05）。结论根管治疗1年后，根尖周病变区域的分形维数增加。糖尿病对分形维数增加具有负面影响。