A reduced number of teeth in the dental arch may be caused by their eruption stopping, slowing down or being delayed. A tooth that for some reason hasn’t erupted is called impacted. It may be partially or fully formed, part of the normal set or supernumerary, and located in various positions and at various depths.
Rare cases have been described of impacted teeth located in the nasal and maxillary sinuses, in the ramus of the lower jaw and even in the eye socket.
There is a clinical form of impaction – “semi-impacted”. This refers to teeth whose crowns have appeared under the mucosa, but whose eruption has stopped for some reason. Impacted teeth continue to develop inside the bone: their roots grow, the enamel mineralizes, and so on.
Impacted teeth may stay in the bone for a long time without causing any sensations. Very rarely, they may cause trigeminal neuralgia. The development of retention (follicular) cysts is also a potential danger.
Impacted teeth may cause resorption of the roots of neighboring teeth, rotation around their axis, or tilting towards the lips or tongue. The teeth most often impacted are the upper canines, central incisors, lateral incisors, lower canines and second premolars. Among anomalies of tooth position and dental arch deformities, canine impaction accounts for 30.5%, and among tooth impactions in general, according to various sources, canine impaction occurs in 70.77% of cases. Impaction of the upper canines is the most common. These teeth are positioned towards the palate in 85% of cases and towards the lips in only 15%.
Causes of tooth impaction:
General causes of delayed eruption and impaction of whole groups of teeth include metabolic disorders, in particular disrupted nucleic acid metabolism at tissue level (Griva, Mecher, 1979), infectious and severe general diseases, and diseases of the endocrine glands, especially the thyroid and parathyroid glands, and pituitary dysfunction. With myxedema, baby teeth are replaced late, and as a result permanent teeth erupt late.
Local causes are very diverse and mainly cause impaction of individual teeth. They include supernumerary teeth or growths that directly obstruct the teeth. Impaction and semi-impaction may also be caused by a tooth bud being displaced by trauma.
Early extraction of baby teeth causes permanent teeth to shift and take the place of other teeth. For example, early extraction of second baby molars (second chewing teeth) causes the first permanent molar to tilt forward. As a result, after the first premolars erupt there is no room left for the second premolars, which remain impacted or erupt towards the lips or tongue. The frequency of canine impaction is mainly explained by lack of space. Impaction is diagnosed after a clinical examination and X-rays. A dental X-ray, a panoramic X-ray or computed tomography may be taken.
There are 3 methods of bringing impacted teeth into place: orthodontic, orthodontic-surgical and surgical.
The treatment method depends on the patient’s age, the position of the impacted tooth in the alveolar ridge, how developed the tooth is, the cause of the problem and whether there is space in the dental arch.
The most common method for treating impacted teeth is orthodontic. This method is based on functional stimulation.
Treatment by functional stimulation is carried out with removable plates. They are specially modeled so that when the mouth closes, a slight load falls on the top of the impacted tooth, which stimulates the local tissues, speeds up bone remodeling and helps the tooth erupt.
This method is advisable when the tooth is positioned vertically and close to the alveolar ridge. With the functional stimulation method, it’s hard to predict the results, because the effect of treatment varies. The impacted tooth may erupt, or it may not. Bringing an impacted tooth back into the dental arch takes patience from both the patient and the doctor.
To speed up treatment and make it more effective, the orthodontic-surgical method is becoming increasingly popular. With this method, the exact location of the tooth is determined from X-rays or computed tomography. A mucosal flap is lifted and, if necessary, a bony “window” is cut; then the orthodontist fixes a bracket on the impacted tooth, which is attached to the archwire with a special chain or ligature.
When planning treatment, a number of factors must be taken into account: the aesthetic and functional value of the impacted tooth, the patient’s age, the position of the impacted tooth in the alveolar ridge, the right choice of treatment plan, the condition of the dental arch in the area of the missing tooth, and the patient’s consent to long-term treatment.
Once back in the dental arch, impacted teeth function as full teeth and can be used as supports in prosthetic treatment.
