3,5�C14,17,18,23 The data for hypodontia, excluding the third molars, in both genders combined varies from 0.3% Nilotinib molecular weight in the Israeli population3 to 11.3% in the Irish13 and 11.3% in Slovenian populations.20 The different findings could be explained by the variety in the samples examined in terms of age range, ethnicity and type of radiographs used for evaluation. Table 1 Comparison of findings of hypodontia in various populations. As a rule, if only one or a few teeth are missing, the absent tooth will be the most distal tooth of any given type24 i.e. lateral incisors, second pre-molars and third molars. In many populations, it has been demonstrated that, except third molars, the most commonly missing teeth are the maxillary lateral incisor, mandibular and maxillary second premolar.

3,10,15,20 According to Jorgenson24 the mandibular second premolar is the tooth most frequently absent after the third molar, followed by the maxillary lateral incisor and maxillary second premolar, for Europeans. In the literature, hypodontia was found more frequently in females than males.2,3,4,7,20 Most authors report a small but not significant predominance of hypodontia in females, but statistically significant differences have been found in some researches.2,3,4,7 Many studies have demonstrated that there is no consistent finding as to which jaw has more missing teeth. In the literature, few studies have compared the prevalence rates of tooth agenesis between the anterior and posterior regions and showed the distribution of missing teeth between the right and left sides.

Literature search in June 2006 revealed no previous studies about the prevalence of hypodontia in the permanent dentition in Turkish population and in Turkish orthodontic patients. The aim of this study was to document the prevalence of hypodontia in the permanent dentition among a group of Turkish sample who sought orthodontic treatment and to compare present results with the specific findings of other populations. The occurrence was evaluated in relation to gender, specific missing teeth, the location and pattern of distribution in the maxillary and mandibular arches and right and left sides. MATERIALS AND METHODS A total of 4000 orthodontic patient files from the Department of Orthodontics of Erciyes University, Kayseri and K?r?kkale University, K?r?kkale were reviewed.

The patient files (panoramic radiographs, specific periapical radiographs, dental casts, anamnestic data), were the only sources of information used to diagnose hypodontia.21 If an accurate diagnosis of hypodontia could not be made, the files were excluded. Moreover, radiographs of patients with any syndrome or cleft lip/palate were excluded from the study. The Dacomitinib patients had no previous loss of teeth due to trauma, caries, periodontal disease, or orthodontic extraction. A total of 2413 patients�� records of sufficient quality were selected.