The inclusion criteria was type II diabetes mellitus and the exclusion criteria was illiterate patients and subjects who were unable to fill out the questionnaires. This project was approved by Ethics and Research committee of Deputy of Research and Technology, Babol University of Medical Science. Procedural steps and the aim of the study were explained to participants initially. Duration of diabetes and demographic information including age, gender, occupation were recorded; Moreover, questions were asked about wearing removable prosthetic appliances, smoking and 9 questions about xerostomia. In xerostomia context, if 5 questions had positive answers, xerostomia was confirmed [12,13]. Data about disease, including level of the control of diabetes (HbA1c), presence of other systemic diseases, medications used and type of anti-diabetic medication used, were recorded. Besides, each patient’s opinion about their self-perceived oral and general health and their need for dental treatments were asked and recorded. Subsequently, two questionnaires related to OHRQoL, GOHAI-Per and OHIP-14-Per which were validated by Motallebnejad et al. (9) and Motallebnejad et al. (10), were completed by patients.