Tooth gemination

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Tooth gemination
Specialty Dentistry

Tooth gemination is a dental phenomenon that appears to be two teeth developed from one. There is one main crown with a cleft in it that, within the incisal third of the crown, looks like two teeth, though it is not two teeth. The number of the teeth in the arch will be normal.


Signs and symptoms


The cause of gemination is still unknown. [3] However, there are a few possible factors contributing to gemination:


The phenomenon of gemination arises when two teeth develop from one tooth bud and, as a result, the patient has an extra tooth, in contrast to fusion, where the patient would appear to be missing one tooth. Fused teeth arise through union of two normally separated tooth germs, and depending upon the stage of development of the teeth at the time of union, it may be either complete or incomplete. On some occasions, two independent pulp chambers and root canals can be seen. However, fusion can also be the union of a normal tooth bud to a supernumerary tooth germ. In these cases, the number of teeth is also normal and differentiation from gemination may be very difficult, if not impossible. In geminated teeth, division is usually incomplete and results in a large tooth crown that has a single root and a single canal. It is an asymptomatic condition.

The prevalence of gemination or fusion is 2.5% in primary dentition, [1] and 0.1 - 0.2% in permanent dentition. [4] It is more frequently observed in primary than permanent dentition; anterior than posterior teeth; [5] unilaterally than bilaterally. [1] It commonly occurs in the primary upper incisors.



Before root canal treatment or extraction are carried out, the clinician should have thorough knowledge about the root canal morphology to avoid complications.

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Human tooth

The human teeth function to mechanically break down items of food by cutting and crushing them in preparation for swallowing and digesting. Humans have four types of teeth: incisors, canines, premolars, and molars, which each have a specific function. The incisors cut the food, the canines tear the food and the molars and premolars crush the food. The roots of teeth are embedded in the maxilla or the mandible and are covered by gums. Teeth are made of multiple tissues of varying density and hardness.


Hyperdontia is the condition of having supernumerary teeth, or teeth that appear in addition to the regular number of teeth. They can appear in any area of the dental arch and can affect any dental organ. The opposite of hyperdontia is hypodontia, where there is a congenital lack of teeth, which is a condition seen more commonly than hyperdontia. The scientific definition of hyperdontia is "any tooth or odontogenic structure that is formed from tooth germ in excess of usual number for any given region of the dental arch." The additional teeth, which may be few or many, can occur on any place in the dental arch. Their arrangement may be symmetrical or non-symmetrical.

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Hypodontia Developmental absence of one or more teeth excluding the third molars

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Human tooth development

Tooth development or odontogenesis is the complex process by which teeth form from embryonic cells, grow, and erupt into the mouth. For human teeth to have a healthy oral environment, all parts of the tooth must develop during appropriate stages of fetal development. Primary (baby) teeth start to form between the sixth and eighth week of prenatal development, and permanent teeth begin to form in the twentieth week. If teeth do not start to develop at or near these times, they will not develop at all, resulting in hypodontia or anodontia.


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Tooth fusion arises through union of two normally separated tooth germs, and depending upon the stage of development of the teeth at the time of union, it may be either complete or incomplete. On some occasions, two independent pulp chambers and root canals can be seen. However, fusion can also be the union of a normal tooth bud to a supernumerary tooth germ. In these cases, the number of teeth is fewer if the anomalous tooth is counted as one tooth. In geminated teeth, division is usually incomplete and results in a large tooth crown that has a single root and a single canal. Both gemination and fusion are prevalent in primary dentition, with incisors being more affected.

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  1. 1 2 3 4 5 6 7 8 Süha Türkaslan, Hasan Suat Gökçe and Mehmet Dalkız (July 2017). "Esthetic Rehabilitation of Bilateral Geminated Teeth: A Case Report". European Journal of Dentistry. 1 (3): 188–191. PMC   2638247 . PMID   19212565.
  2. 1 2 3 4 5 6 7 Nandini DB, Deepak BS, Selvamani M, Puneeth HK (2014). "Diagnostic dilemma of a double tooth: a rare case report and review". Journal of Clinical and Diagnostic Research. 8 (1): 271–2. doi:10.7860/JCDR/2014/6556.3928. PMC   3939503 . PMID   24596793.
  3. 1 2 3 4 5 6 "Tooth gemination in dentistry". DentaGama Dental Social Network. DentaGama. Retrieved 1 December 2017.
  4. E. Grammatopoulos (11 Aug 2007). "Gemination or fusion?". British Dental Journal. 203: 119–120. doi: 10.1038/bdj.2007.699 .
  5. Siavash Moushekhian, Masoud Shiehzade, Amir Shammas (June 2014). "Treatment Plan and Clinical Management of a Geminated Maxillary Lateral Incisor: A Case Report". JDMT. 3 (2): 87–90.
  6. Spuller RL, Harrington M (1986). "Gemination of a maxillary permanent central incisor treated by autogenous transplantation of a supernumerary incisor: case report". The American Academy of Pediatric Dentistry. 8 (4): 299–302. PMID   3472179.