Investigation of maxillofacial morphology and oral characteristics with Turner syndrome and early mixed dentition.

Turner syndrome is associated with an X chromosome abnormality in women and is characterized by infantilism, congenital webbed neck, and cubitus valgus. The aim of this study was to determine the maxillofacial morphology and oral characteristics of Japanese girls (mean age, 8.5 years) with Turner syndrome and early mixed dentition. Lateral cephalograms obtained at the first visit were used to analyze maxillofacial morphology. Oral characteristics were identified using orthopantomograms, intraoral photographs, and study casts. All patients received growth hormone. Lateral cephalograms showed a retrognathic maxilla and mandible and a small gonial angle. Nine patients had a high-arched palate. Nine patients had class II first molar relationship occlusion and one had mesial step-type occlusion. Three patients showed ectopic eruption of the maxillary first permanent molar accompanied by resorption of the maxillary second primary molar. Eruption of the permanent teeth tended to occur early. The median mesiodistal diameter of the maxillary central incisor was smaller than the Japanese norm. Ectopic eruption of the maxillary first permanent molar may be caused by lack of eruption space and a discrepancy between bone growth and timing of tooth maturation.