Single median maxillary central incisor syndrome and its clinical importance.

Single median maxillary central incisor (SMMCI) is a rare dental anomaly. It may occur in association with other systemic abnormalities (short stature, pituitary insufficiency, microcephaly, choanal atresia, midnasal stenosis, and congenital nasal pyriform aperture stenosis) and may also be a feature of recognized syndromes or specific chromosomal abnormalities (2).The aim of this report is to introduce the syndrome of SMMCI to pediatricians and dentists. We try to remind the significance of SMMCI as an indicator of potential holoprosencephaly and other abnormalities in the next generation.A-9-year old girl was brought to our hospital because of growth retardation. She was bom from healthy, non-consanguineous parents in 38,h week of gestation after an uncomplicated pregnancy. Family history was unremarkable. Other relatives did not have single central maxillary incisors, or oral clefts. The height, weight, and head circumference at birth were normal. Shortly after birth, noisy breathing and respiratory distress owing to nasal obstruction were observed. Feeding was difficult, and there were episodes of cyanosis and apnea. A nasal suction catheter could pass on both sides through the nares and choanal atresia was not detected. On physical examination, she was of normal intelligence. Weight (18.3 kg) and height (122.4 cm) were below the 3rd percentile. Single central incisor teeth in the upper jaw were observed (Fig. 1). Physical, neurological, examinations revealed no further abnormalities. Laboratory investigations including complete endocrinologie workup were normal. Skeletal X-rays showed normal findings. Abdominal ultrasound, echocardiography, cranial (computerized tomography and magnetic resonance) imaging were normal. Genetic analysis revealed normal karyotype. She was diagnosed as SMMCI and was sent to Ankara University Faculty of Dentistry Department of Pedodontics and Orthodontics for dental evaluation. Dental examination showed only one maxillary central incisor situated exactly in the midline and had no history of tooth loss from trauma or extraction in the anterior region. The patient had early deciduous tooth loss because of decay and lack of oral hygiene. Needed extractions and restorations were made. However the patient did not come to the follow-up.The frequency of a SMMCI has been estimated as 1 in 50.000 newborns (2). Its clinical spectrum is highly variable. It may possibly occur as an isolated trait (5) or may be involved with midline structures of the head including the cranial bones, the maxilla and its contained dentition, the nasal airways (choanal atresia, midnasal stenosis or congenital pyriform aperture stenosis), and sometimes brain (holoprosencephaly), together with other midline structures of the body (2). Cardiac-skeletal-genitourinary tract abnormalities, endocrine disorders and malignancies may be accompanied (5). Holoprosencephaly spectrum is the most described association with SMMCI. From this point of view the dentists and pediatricians should be aware of the anomalies seen together with SMMCI and the importance of a multidisciplinary approach to rule out other craniofacial or midbrain abnormalities. …