Epithelial metabolism evaluation in radicular cysts by the AGNOR technique

Introduction: Radicular Cyst (RC) development is associated with the activation and proliferation of epithelial rests of Malassez. This occurs due to inflammatory stimuli resulting from bacteria proliferation in the root canal of a non-vital tooth. When the tooth is removed, the cyst becomes known as Residual Cyst (ReC). The RC common treatment is the endodontic therapy, with the aim of eliminating the inflammation in the periapical region. Nonetheless, this treatment is not always effective and the cyst may continue to grow, what happens in most cases of ReC.Objective: To evaluate the metabolism of the RC and ReC epithelial lining through the technique of AgNOR quantification and of the influence of the presence of inflammation in the growth of these cysts.Material and method: 20 cases of RC and 10 of ReC, were processed by the AgNOR technique. The AgNOR quantitative analysis was performed using the "Counting cells" software. The statistical post-hock Newman-Keuls test was applied to compare the RC and ReC mean number of AgNORs in inflamed and non-inflamed areas.Result: Statistically significant difference (p=0.0094) was observed between inflamed (1.86±0.26) and non-inflamed (1.65±0.20) areas. No statistically significant difference (p=0.37) was observed in the comparison between RC (1.81±0.28) and ReC (1.73±0.16).Conclusion: Inflammation interferes in the epithelial metabolism of RC and ReC, reflectings the action of growth factors in epithelial proliferation and contributing to the growth of the cyst, regardless the presence of the etiologic factor associated with the injury origin.

引言：根尖周囊肿（Radicular Cyst，RC）的发生与马拉塞上皮剩余的活化及增殖密切相关，该过程由无髓牙根管内细菌增殖引发的炎症刺激所介导。当患牙被拔除后，此类囊肿即被称为残余囊肿（Residual Cyst，ReC）。根尖周囊肿的常规治疗方案为牙髓治疗，目标是消除根尖周区域的炎症反应。然而，该治疗并非总能取得理想效果，囊肿仍可能持续生长，在多数残余囊肿病例中均存在此类情况。

目的：通过银染核仁形成区嗜银蛋白（AgNOR）定量技术，评估根尖周囊肿与残余囊肿上皮衬里的代谢状态，并探究炎症存在对这两类囊肿生长的影响。

材料与方法：选取20例根尖周囊肿标本与10例残余囊肿标本，采用AgNOR染色技术进行样本处理。使用"Counting cells"软件完成AgNOR定量分析。采用纽曼-基尔斯事后检验（Newman-Keuls post-hoc test）进行统计学分析，以对比根尖周囊肿与残余囊肿在炎症区域与非炎症区域的平均AgNOR计数。

结果：炎症区域（1.86±0.26）与非炎症区域（1.65±0.20）之间的差异具有统计学意义（p=0.0094）。根尖周囊肿组（1.81±0.28）与残余囊肿组（1.73±0.16）之间未观察到具有统计学意义的显著差异（p=0.37）。

结论：炎症可干扰根尖周囊肿与残余囊肿的上皮代谢，反映出生长因子在上皮增殖过程中的调控作用，并促进囊肿生长，且该效应与损伤起源相关的致病因素是否存在无关。