Dental development in children with mild-to-moderate hypodontia Emine S ¸ en Tunc ¸, a S ¸ ule Bayrak, a and Alp Erdin Koyut € urk b Samsun, Turkey Introduction: The aim of this study was to compare dental development in a group of children with mild- to-moderate hypodontia with a matched group. Methods: A study group of 70 children (43 girls, 27 boys) with hypodontia, aged 5.3 to 12.5 years, was matched for race, age, and sex with 140 healthy, normal control subjects. The children’s dental ages were calculated by using a modified dental-age estimation method. Differences between dental and chronologic ages were analyzed by t tests, and the correlations between differences in dental and chronologic ages and the numbers of missing teeth were analyzed with the Spearman correlation test. Results: Dental development in children with mild-to-moderate hypodontia was significantly delayed compared with the control group (P \0.05); however, the mean difference did not exceed 0.3 years in either sex. No correlation was observed between the differences in dental and chronologic age and the severity of hypodontia. Conclusions: Children with mild-to-moderate hypodontia had delayed dental development of a few months; this was statistically significant. Because of individual variations, each patient should be carefully examined. (Am J Orthod Dentofacial Orthop 2011;139:334-8) O ne of the most common polymorphisms is hypo- dontia, the absence of at least 1 tooth, excluding the third molar. 1 The prevalence of hypodontia in the permanent dentition has been reported to be 0.3% to 10.1%, depending on the population studied. 2,3 Hypodontia is classified according to the severity of the condition, with “mild-to-moderate hypodontia” used to denote the absence of 2 to 5 teeth and “severe hypodontia” denoting the absence of 6 or more teeth. 4 Early diagnosis and effective clinical management of hypodontia are important because the condition can lead to esthetic, physiologic, and functional problems such as malocclusion, periodontal damage, and inhibited alveolar growth. 5 The management of absent teeth generally involves a multidisciplinary approach. 6 The number, size, and development of the remaining teeth are significant factors in long-term treatment planning. 7 Hypodontia has been reported to be associated with other dental abnormalities, including microdontia, 8 transpositions, 9 and taurodontism. 10 Hypodontia can also be associated with delayed tooth formation 7,11-13 ; however, there is no consensus in the literature concerning this latter phenomenon. 7,11-14 In this retrospective, cross-sectional study, we aimed to compare dental development in a group of children with mild-to-moderate hypodontia and a matched group and to determine whether the severity of the hypodontia has an effect on dental development. MATERIAL AND METHODS Hypodontia subjects were selected based on radio- graphs of patients who previously applied to the Depart- ment of Pediatric Dentistry at the Ondokuz Mayis University Faculty of Dentistry in Samsun, Turkey. In most cases, the patients were referred to the pediatric dental clinic because of caries-related pain or traumatic dental injuries. Patients with developmental anomalies such as ectodermal dysplasia, cleft lip or palate, and Down syndrome, as well as patients who had undergone previous orthodontic treatment, were excluded from the study. In previous studies, panoramic radiograph examinations were found to be a reliable method of diagnosing hypodontia. 6,15,16 In this study, a tooth was diagnosed as congenitally missing when no mineralization of its crown could be identified on the panoramic radiographs, with no evidence of its having been extracted. Third molars were excluded. A total of 70 subjects (43 girls, 27 boys) were identified as From the Department of Pediatric Dentistry, Faculty of Dentistry, Ondokuz Mayıs University, Samsun, Turkey. a Assistant professor. b Associate professor. The authors report no commercial, proprietary, or financial interest in the products or companies described in this article. Reprint requests to: Emine S ¸en Tunc ¸, Ondokuz Mayıs University, Faculty of Dentistry, Department of Pediatric Dentistry, 55139 Samsun, Turkey; e-mail, sentunc@yahoo.com. Submitted, September 2008; revised and accepted, April 2009. 0889-5406/$36.00 Copyright Ó 2011 by the American Association of Orthodontists. doi:10.1016/j.ajodo.2009.04.024 334 ORIGINAL ARTICLE