Hijawi and Mohammad, 2015 Journal of Basic and Applied Research 1 (2): 48-54 www.jbaar.com 48 INTRODUCTION Supernumerary teeth (Hyperdontia) is the condition of having extra teeth that develop in addition to twenty deciduous, and thirty two permanent.(Rallan, Rallan et al. 2013) The etiology of supernumerary teeth is not well known. Supernumerary can occur anywhere in the dental arch as a result of a rare alteration in odontogenisis. Many theories exist for hyperdontia, One theory states that hyperdontia is formed as a result of a dichotomy of the tooth bud is split to create two teeth. The second is the hyperactivity theory, most accepted worldwide, which proposes that hyperdontia is initiated as a result of local, independent, conditioned hyperactivity of the dental lamina. Furthermore, Heredity plays an important role in the occurrence of hyperdontia, but does not follow a simple Mendelian pattern. A familial tendency and linked to the X chromosome. (Brook 1984; Liu 1995) Above all, cleidocranial dysplasia, cleft lip/palate and other syndromes are associated with multiple supernumerary teeth, where develop but fail to erupt. Supernumeraries complications like crowding, delayed eruption, dilacerations, rotation, malalignment, or displacement of permanent tooth, impaction, abnormal diastema, cystic lesions, ectopic eruption, root resorption of adjacent teeth. As a consequence an early diagnosis allows an early intervention leading to better prognosis.(Sharma and Singh 2012). Abstract: The purpose of the present study was to investigate the incidence of the supernumerary teeth among Palestinian according to sex, location and morphology. This retrospective study was carried out using 1683 panoramic radiographs (719 males, 964 females) aged seven and older. The supernumerary teeth were observed in 11 (0.65%) panoramic (4 males, 7 females) with (1:1.75) male female ratio. two cases of them showed bilaterally hyperdontia. The premolar was found to be the most common supernumerary, followed by mesiodens and distomolar. The incidence of supernumerary teeth was found to be 0.77%, and we demonstrate that parapremolar the most common in the mandible. Received: 15-5-2015 Revised: 9-6-2015 Published: 15-6-2015 Keywords: Hyperdontia, Incidence, Panoramic radiography, Supernumerary teeth, Tooth morphology. Radiographic Assessment of the Incidence of Supernumerary teeth in a population of 1683 patients (Preliminary study) Saleh I. Hijawi * , Ziyad K.M. Mohammad 1 Conservative and Prosthodontic Department, Faculty of Dentistry, Arab American University, Jenin, Palestine. *corresponding author: saleh_hijawee@hotmail.com; hijawis@gmail.com