In upper third molars, and on occasion with fused roots, second molars, the roots can be fused together. This is a variation, not a pathological condition. Shovel shaped incisors display enhanced marginal ridges and present with a distinctive shovel-shaped appearance on the lingual aspect. They appear frequently in many persons of Asian origin, including many Native American Indians. The diagnosis can be confirmed if there is a reduction in the number of teeth that are present in the dental arch.
Some authors refer to fusion as 'syndontism'.
It is an incomplete twinning of the gooth germ. In gemination, there is a shared pulp and root. Some writers refer to gemination as 'schizodontism'. It occurs after tooth formation is complete. Usually this condition is 'silent' without clinical significance.