798H
Fig. 13.8 Megadont tooth 11, absent
tooth 12.799H
Fig. 13.9 Isolated microdontia affecting
22 in a female. Gingival architecture
suggestive of occult cleft.13.4.2 Root size
Root length appears to be subject to some racial variation, with shorter roots being
seen in people of Oriental background and larger roots in patients of African origin.
Large root size
Larger than normal roots are most typically seen affecting the permanent maxillary
central incisors, with a population prevalence in one Swedish study of 2.3%. Males
were four times more likely to be affected than females.
Small root size
Short-rooted teeth in the primary dentition may be associated with other dental
abnormalities. Short roots may also be seen in a number of conditions affecting the
dentine and/or pulp. These will be considered in a later section.
Short roots may be seen affecting the permanent maxillary central incisors. The
shortening affects approximately 2.5% of children and some 15% of these may have
shortened roots on other teeth, most often premolars and/or canines. The cause is
often unknown, though this can occur as a result of orthodontic treatment.
In regional odontodysplasia (800HSection 13.7.1) there is typically abnormal root
formation as well as abnormalities of the crowns of the teeth.
Irradiation of the jaws, or chemotherapy, during the period of root formation may lead