Tooth Gemination - Etiology, Clinical Features, and Management

What Is Gemination?

Gemination is termed a developmental dental anomaly wherein there is the formation of two crowns or a double crown that originates only from a single tooth. In this condition, two crowns or a double crown are observed in an individual, either in primary or permanent teeth. These anomalies originate embryologically due to aberrations between the ectodermal or mesodermal layers. Also, a double crown still signifies that the origin of the crowns is from a single tooth germ only.

What Is the Difference Between a Geminated and a Fused Tooth?

Gemination is very similar to fusion but it is still different as in fusion two different teeth unite or merge as one tooth. In fusion, when counting the teeth, there is one less than normal because two teeth have fused to form a single crown. Fusion is believed to occur as a result of physical force or pressure exerted on the adjacent tooth germ during its development, leading to the contact and subsequent fusion of two tooth buds just before the process of tooth bud calcification. Gemination and fusion may appear clinically similar which needs a clear dental assessment by a dentist to count the number of teeth in the arch, which can provide a correct diagnosis of this condition alone.

What Is the Prevalence Rate of Gemination?

Gemination is a condition that occurs more prevalently, especially in the anterior maxillary region. Globally, the prevalence rates of gemination occurring unilaterally or on a single segment are approximately 0.5 percent in deciduous or primary teeth. In adult or permanent dentition, the prevalence rates of this developmental disturbance are around 0.1 percent. There are also certainly case reports of observed bilateral gemination, although it is comparatively less common. The prevalence of bilateral cases in the primary dentition ranges from 0.01 percent to 0.04 percent, while in the permanent dentition, it ranges from 0.02 percent to 0.05 percent.

What Is the Etiology of Gemination?

Although the etiology of gemination is said to be unknown and has an elusive origin according to dental research, there is still some research evidence that demonstrates the potential familial tendency of gemination, indicating that this condition may run in families. There are multifaceted causes responsible for gemination, usually resulting from complex interactions among various genetic and environmental factors involved in this developmental disturbance.

This developmental anomaly not only causes clinical problems such as impaired appearance or aesthetic tooth appearance but can also lead to periodontal problems, dental caries in the affected teeth, and tooth crowding in the segment where gemination occurs. The etiology of geminated teeth can vary due to a broad range of factors associated with aberrations in the ecto and mesoderm layers. These factors may include:

• Nutritional deficiencies.

• Endocrine influences or endocrinal disorders.

• Infectious or inflammatory diseases or pathologies.

• Excessive systemic ingestion of drugs.

• Hereditary or congenitally linked disorders.

• Local trauma or infection.

• Ionizing radiation.

What Are the Other Terminologies for Tooth Gemination?

Other commonly used terminologies used for denoting gemination include:

1. Double teeth.

2. Double-formed teeth or double-formation teeth.

3. Joined teeth.

4. Fused teeth.

5. Dental twinning refers to the tooth crown in gemination condition only.

What Are the Clinical Features That Can Occur With Gemination?

The clinical problems that arise when twinning occurs, especially in the front or anterior teeth, are as follows:

• Tooth malalignment can occur.

• Noticeable interdental spacing or evident gaps between teeth.

• There may be potential tooth arch asymmetry.

• Individuals may experience social embarrassment due to aesthetic issues or an unpleasant appearance of the front teeth.

• Periodontal involvement of the affected tooth can lead to gum disease and bone loss in the affected tooth region.

• There may impede the eruption of the adjacent tooth next to the twinned tooth.

• Deep grooves are typically present in geminated teeth, making it easier for food to get lodged, resulting in complaints of food deposits. This also increases susceptibility to dental caries formation.

• If the defects or deep dental grooves present in the geminated tooth are deeper (extending to the gingival third of the tooth), there is a higher chance that the individual will develop severe consequences of gingival and subsequent periodontal disease. This is because it becomes a central point where bacterial ingress occurs, and dental plaque accumulates very easily.

How Can Gemination Be Managed?

The management of gemination involves several steps. The diagnosis plays a major role in treatment planning. As mentioned earlier, the dentist differentiates gemination from fusion by counting the number of teeth in the patient's arch. If the number of teeth is one less, then the tooth is fused, not geminated. The dentist will then obtain a thorough case history, medical history, and family history, and perform clinical and radiographic examinations to confirm the diagnosis.

The mainline treatment for gemination is endodontic treatment. In complicated cases with periapical lesions (pathological conditions that occur around the apex or tip of a tooth's root), orthograde treatment may also be performed on the geminated teeth. Understanding the morphological outline and internal anatomy of the root canal through radiographic examination is very important before initiating endodontic treatment. The dentist should adhere strictly to the biomechanical principles of root canal preparation. Simultaneously, the patient should be given instructions and advised to maintain strict plaque control in the affected region.

Conclusion

Gemination is thus a globally occurring dental anomaly and a morphological tooth alteration that can affect the patient's esthetics and functions. This condition can occur in both primary and permanent teeth and needs to be differentiated from fusion by the dentist. Clinical and radiographic examination plays a crucial role, and management is mostly done through endodontic therapy.