Dystopic tooth

Among the numerous dental problems, there is one more - a dystopic tooth, that is, located incorrectly (from the Greek dystopia - incorrect location or lack of space) or erupted in the wrong place.

Epidemiology

As dental statistics show, almost a quarter of patients have dystopic teeth to varying degrees. And more than half of patients with dental anomalies have some kind of dental dystopia.

As for the delay in eruption (retention) of teeth, then, according to orthodontists, among patients of childhood and adolescence, this anomaly is observed in 15-20% of cases, and up to half of them accounts for canine retention.

Sandham and Harvie  [1] conducted a study of Scottish schoolchildren and concluded that 0.38% had dystopic teeth out of a sample of 800, which was confirmed by a study in India, where the incidence was 0.4%. Thilander and Jakobsson  [2] reported 0.26% prevalence among Swedish schoolchildren. According to Peck and Peck  [3] and Feichtinger et al. [4] dystopic teeth are equally found in both sexes.

Causes of the dystopic tooth

Most often, the causes of dental dystopia can be associated with:

• inconsistency with the age and physiological norms of the timing of teething and its sequence;
• early or premature loss of temporary (deciduous) teeth;
• intrauterine odontogenesis disorders -  dental anomalies ;
• underdevelopment of the alveolar processes of the jaws, narrowing of the dental arches and other  anomalies and deformities of the jaws , including those accompanying chromosomal syndromes;
• incomplete number of teeth (oligodentia);
• extra ( supernumerary ) teeth -  hyperdontia ;
• pathology of the dentition in the form of crowding of teeth, especially in the early period of the mixed dentition - due to the deficiency of the jaw bone and the inconsistency of its size with the permanent teeth, which are larger than the milk ones;
• anomalies in the size and shape of teeth: an increase in the width of the crowns of the teeth (upper central incisors or small molars) - macrodentia or an increase in the roots of the teeth - taurodontism (taurodontism). [5]

For example, frequent dystopia of wisdom teeth is due to both the late period of their eruption, and the localizations of the data by the molar - they are the last in the dentition. 

In addition, the result of a violation of the formation of teeth is considered to be retention (in Latin, retentio means retention) - a delay in the eruption of a tooth. If a tooth does not erupt, remaining in the bone of the alveolar part of the jaw or mucous tissues of the gums, or has erupted partially, it is called impacted (in the second case, partially impacted). This happens most often with the lower wisdom teeth, lower second premolars, and upper canines. [6]

There can also be an impacted and dystopic tooth at the same time, that is, both growing incorrectly and "stuck" in the jaw.

Risk factors

Experts call such risk factors for the appearance of dystopic teeth, such as:

• the presence of a genetic predisposition; [7]
• pathology of pregnancy;
• early extraction of milk teeth (leading to a delay in the eruption of permanent teeth);
• trauma to the jaw or its alveolar part;
• high levels of radiation;
• rickets ;
• endocrine insufficiency associated with disturbances in the hypothalamus (or pituitary gland);
• hypothyroidism;
• diabetes;
• violation of nasal breathing.

Pathogenesis

A person is characterized by diphiodontism, and when changing milk teeth (of which there are two dozen in children by the age of 2.5 years), permanent ones (which in adults should normally be 32), certain deviations may occur.

So, dystopia of canines, which are cut in children with a mixed bite (after 9-10 years), is often the result of a lack of space for their correct location in the alveolar part of the gum or already existing disorders of the dentition.

A dystopic wisdom tooth (third molar) is erupted at the age when the ossification of the skeleton is nearing completion (up to 25 years); in addition, it appears in a place where there was no milk tooth before it, and this leads to difficulties in erupting.

The exact mechanism of dental dystopia in the process of odontogenesis is unknown, but researchers associate it with hereditary features of the formation of dental germs during intrauterine development (from the fifth week of gestation), as well as teratogenic effects (ionizing, chemical) on the fetus - since not only milk buds are formed, but and permanent teeth such as first molars, incisors, and canines. The formation of the rudiments of the remaining permanent teeth occurs in childhood, and the pathogenesis of dystopia may be due to impaired intestinal calcium adsorption in rickets; a possible deficiency of the pituitary growth hormone somatotropin (which ensures the maturation of tooth buds and their eruption); insufficient level of thyroid hormones in its pathologies (thyroid-stimulating hormones in a certain way affect the secretion of growth hormone); excess glucose in the blood (hyperglycemia) in diabetes mellitus. [8]

Teeth retention is most often explained by the fact that the tooth germ is abnormally located, it can be pinched between the converging (or accrete) roots of already erupted adjacent teeth, or it is blocked by a gingival cyst or odontogenic tumor.

Symptoms of the dystopic tooth

Symptoms of teeth dystopia depend on the type of their abnormal position:

• with vestibular dystopia, the tooth erupts in front of the dentition;
• with the oral - behind the dentition with the displacement of the tooth into the oral cavity;
• with mesial - the tooth grows in the dentition, but has an inclination forward (outward);
• with distal - the tooth is deflected posteriorly (inside the dentition).

Localization of a dystopic tooth above the dentition is a sign of its supraposition, and eruption below the dentition is called infraposition. Also, a tooth during eruption can turn around its axis, and in this case we are talking about cake position. And when the teeth "change places" (that is, the tooth erupts in place of the adjacent tooth), then the anomaly is defined as transposition. [9]

A long enough impacted and dystopic tooth does not manifest itself in any way, and it is detected only during radiography. [10]

But a dystopic wisdom tooth (especially often the lower one) can erupt with pain and restriction of opening the mouth, hyperemia and swelling of the surrounding tissues, as well as the development of their inflammation -  pericoronitis  (pericoronitis). [11]

Complications and consequences

Dystopia of the teeth has serious consequences and complications in the form of:

• malocclusion ;
• traumatic damage to the gums and mucous membranes of the oral cavity with the formation of tissue erosion and painful ulcers;
• the formation of gingival pockets;
• increased plaque formation;
• enamel lesions by caries;
• the development of inflammation of the periosteum of the jaw (with the formation of submandibular phlegmon), the pulp of the tooth or the shell of its root (with possible abscess);
• formation of basal cysts. [12]

Diagnostics of the dystopic tooth

A routine examination of the teeth and oral cavity and fixing the patient's complaints, with which any diagnosis in dentistry begins, is not enough to identify a dystopic tooth. [13]

The maximum information is provided only by visualizing instrumental diagnostics -  orthopantomogram - panoramic radiograph of the maxillofacial region .

In cases of impacted dystopic tooth, computer or MRI  tomography of the maxillofacial region is used .

Differential diagnosis

To determine only dystopia or only retention of teeth, differential diagnosis is carried out. 

Treatment of the dystopic tooth

Is orthodontic treatment of dystopic teeth possible? It depends both on the localization of the incorrectly grown tooth and the type of its abnormal position, and on the nature of the arisen violation of the dentition.

Such treatment is carried out with a permanent bite (that is, after changing all milk teeth), installing braces, special retention plates, splints and arcs; using aligners and aligners  to straighten teeth . More information in the material -  Tooth alignment: basic types . [14]

But surgical intervention - the removal of a dystopic tooth - is sometimes necessary when the correction of dentition disorders is extremely difficult, for example, due to the lack of space in the dental arch. [15]

If there is a high likelihood of a subsequent violation of the location of adjacent teeth and the presence of severe pain or inflammation that has taken on a chronic form, the impacted dystopic tooth is removed (which may require this operation to be performed by a maxillofacial surgeon). [16]

In almost all cases, it is necessary to remove the impacted dystopic wisdom tooth, how this is done, read in the publication -  Removal of a wisdom tooth .

Prevention

To date, there are no special measures to prevent the appearance of incorrectly erupted teeth, as well as anomalies of the dentition. And the early detection of this pathology is facilitated by regular visits to the dentist.

Forecast

A dystopic tooth does not pose a threat to life, but it can cause a curvature of the dentition and a violation of occlusion.