Qualitative and quantitative evaluation of Agnor staining in Odontogenic cysts and ameloblastoma

Background and Objective: Ameloblastoma was a benign odontogenic tumor that has more aggressive behavior in comparison to odontogenic cysts. The of aim the present study is quantitative and qualitative evaluation of silver nitrate staining in ameloblastoma and odontogenic cysts and to compare it with their clinical biologic behavior.  Materials and Methods: In this retrospective cross – sectional study, 60 paraffinized blocks of odontogenic lesions was stained with Agnor. Then for quantitative evaluation, 100 cells with (×100) were counted and their average was considered as NORs count. From qualitative aspect NORs are devided into normal (round- eliptical) to abnormal (large- cluster - bean shap). The results were analyzed statistically by T- Test and ANOVA.  Results: NORs count in ameloblastoma was 2.7± 7.26, in unicystic ameloblastoma 2.5± 7.2, in odontogenic keratocyst 1.8 ± 4.7 and in dentigerous cyst 1.52 ± 2.82. No significance statistical difference was observed in NORs expression between ameloblastoma and unicystic ameloblastoma (P=0.8), But significance statistical difference was observed in NORs expression between ameloblastoma and unicystic ameloblastoma with dentigerous cyst and keratocyst (p < 0.001) (p=0.001). In dentigerous cyst NORs arrangement was normal and intra-nucleous. In keratocyst, NORs were large to bean shape and cluster shapes were seen rearely. Pattern of NORs was seen cluster shape in ameloblastoma and unicystic amelobalstoma.  Conclusion: Number of NORs in ameloblastoma is higher than odontogenic cysts. Distribution pattern of NORs in ameloblastoma are different than odontogenic cysts. Qualitative and quantitative evaluation of silver nitrat staining reflect aggressive behavior of ameloblastoma than odontogenic cysts.