Root length, crown height, and root morphology in Turner syndrome.

Root length, crown height, and root morphology were studied on intraoral and panoramic radiographs in 33 Turner syndrome patients aged 7.0-16.7 years, subdivided on the basis of karyotype. Thirty-three normal girls aged 10.2-16.4 years served as controls. In the 45X patients and, with the exception of a few teeth, also in the isochromosome and mosaic karyotypes, root length and crown height of incisors, canines, and premolars were significantly reduced. Some teeth showed altered crown-root proportions. Maxillary first premolars showed a significantly increased number of two-rooted and three-rooted variants. Mandibular premolars and molars had a complex root morphology, and a classification system was established including four premolar and six molar root types. Premolars had a significantly increased number of root components. Some of the variants, such as a molar-like second premolar, are apparently specific for these patients. On several first molars a radix entomolaris was identified. Two separate mesial and one or two separate distal roots were also frequently seen. Our investigation demonstrates that X-chromosome deficiency influences root formation.