Introduction: The inter - relationship between ABO blood groups & infections has been extensively studied. In this investigation we studied this inter relationship.Methods: 103 patients of Isfahan dental faculty and some clinics that had removable prostheses were studied and the occurrence of denture stomatitis & angular chelitis, and sex & age of them were determined.Results: In this study 49 cases were male & 54 cases were Female. The ranges of their age were between 33-34 years. Among patients (D.S.+) 25 cases were male & 25 cases were female. 62% of patient (D.S.+) has "0" blood type, 50% had "B" blood type, 41% had "A" blood type & 20% had "AB" blood type. 48.5% of all cases had denture stomatitis but only all cases had angular chelitis. All the patients that had angular chelitis soffered from denture stomatitis, too.Discussion: The occurrence of denture stomatitis and angular chelitis varied depending on the blood type of the patients. Especially in blood group "O" compared with other types, both denture stomatitis and angular chelitis were found to be higher or more severe. In the "AB" blood group these infections were found to be less than other blood types.These results suggest that the ABO blood group is one of the etiologic factors of denture stomatitis and that denture wearers of blood group "O" are more susceptible to denture stomatitis.

Introduction: It is necessary to mention that 4% of malignancies include pharyngeal and oral cancers. One of the treatments is radiotherapy in addition with chemotherapy and surgery. Radiotherapy of head and neck can cause some complications with impression on mucos. Regarding this point, we decided to study different effects of radiotherapy on gingival and oral mucosa. Materials & Methods: This descriptive analytical study was performed on 30 patients with head and neck cancers referred to radiotherapy department of Ghaem Hospital. Data collection method included interview, clinical examination and patient’s medical file investigation. The data was collected through relevant forms. The relationship between deferent dosages of radiation on gingival health and oral mucosa was investigated. Data analysis was done with use of GLM, Cochran, MANOVA tests Via SPSS V. 11.5 software. Results: A significant relationship between irritation of oral mucosa ulcer development, mucositis and increase in radiation dosage was observed. But there wasn’s any significant relationship between candidosis, ANUG, PERLECHE and radiation dosage. Periodontal Index (PI), Gingival Index (GI) and Papilla Bleeding Index (PBI) showed on increase, but due to limited time of study, no changes on gingival recession was observed. Plaque Index (PlI) decreased during treatment process due to increase in oral hygiene. Conclusion: There was a direct relationship between oral radiotherapy complications and increase in radiation dosage. With attention to this point that some complications such as ANUG and PERLECHE were not observed, doing a study with longer duration is recommended.