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. When extracting teeth, however, the prudent clinician will carefully examine X-ray films of the patient for this condition. A missed diagnosis can be serious business during an attempted extraction. It is a consequence excessive cementum deposition.