Permanent molar teeth may also be affected. Typically there is a small tubercule on
the occlusal surface of the premolar in the central part of the fissure pattern. The
condition is more common in patients of Chinese descent and has been estimated to
occur in 1-4% of the group. The evaginations are typically fractured off or worn down
by virtue of normal wear, leading to pulpal exposure, pulpal pathology, and periapical
involvement.
Treatment
Careful radiographic evaluation is necessary to determine the extent of any pulpal
extension into the evagination. Restricted and repeated grinding of the tubercule can
be undertaken to promote reactionary dentine deposition on the pulpal aspect of the
evagination. However, this approach may only be applicable in a small number of
cases and, more commonly, removal of the tubercule and a limited pulpotomy are
required.
13.6 ABNORMALITY OF ROOT FORM
13.6.1 Taurodontism
The term taurodontism (literally⎯bull-like teeth, resembling a bull's neck) is used to
describe molar teeth in which the body of the tooth is enlarged vertically at the
expense of the roots. The normal constriction of a tooth at the level of the
amelocemental junction is frequently reduced or absent in affected teeth. The
mechanism leading to taurodontism is the late invagination (or failure) of Hertwig's
root sheath, which maps out the shape of root formation. The furcation is displaced
apically. Varying degrees of taurodontism are seen, with the most extreme example
being when only a single root is present rather than separate roots. Taurodont teeth
may also be described as pyramidal, cuneiform, or fused. The root canal morphology
may have implications when endodontic treatment or extraction is required.
Taurodontism is most commonly recognized in the permanent dentition. Although the
term is traditionally applied only to molars, in some patients with taurodontism of the
molar teeth the pulps of single-rooted teeth may be larger than normal. The
prevalence of taurodontism varies according to the criteria used. In British
schoolchildren a prevalence of 6% for mandibular first permanent molars has been
reported. Higher prevalences have been recorded in certain racial groups such as the
Bantu in South Africa. In some families taurodontism seems to follow an autosomal
dominant pattern of inheritance. Taurodontism has also been considered to be an
atavistic trait. It is found in association with amelogenesis imperfecta, the tricho-
dento-osseous syndrome, ectodermal dysplasias, and a number of other syndromes.
Taurodontism is also more common in X-chromosomal aneudoploidy.
13.6.2 Accessory roots
Accessory roots may occur in almost any tooth. In the primary dentition this most
commonly affects the molars but the primary canines and maxillary incisors can also
be affected. In the permanent dentition, accessory roots are occasionally seen in
maxillary incisors, mandibular canines, premolars, and molars. These accessory roots
are often situated on the distolingual aspect of the tooth, may vary in shape, and may