Tooth crowding (synonyms: Tooth position anomalies; abnormal tooth crowding; anomalous tooth crowding; acquired absence of teeth with defective occlusion; defective bite due to missing teeth; dentition anomaly; impacted tooth with abnormal position; impacted tooth with abnormal position of adjacent teeth; impacted tooth with abnormal position; impacted tooth with abnormal position of adjacent teeth; impacted and displaced canine; impacted and displaced wisdom tooth; retained and displaced tooth; widely spaced teeth; tooth diastema; tooth eruption disorder with abnormal tooth position; tooth malposition; tooth position anomaly; tooth retention with abnormal position of adjacent teeth; tooth rotation; tooth position anomaly; tooth transposition; tooth displacement; overcrowding causing mesiodens; overcrowding causing paramolar; overcrowding causing accessory tooth; overcrowding causing supernumerary tooth; ICD: 10 – K07. 3 – Tooth position anomalies) is always spoken of when there is a disproportion between the size of the jaw and the size of the tooth. In this case, it may be either that the jaw is too narrow but the teeth have a normal width, or the reverse is true, that the teeth are wider than average, resulting in a lack of space.
Symptoms – complaints
Tooth crowding can be located in both the coronal (crownward) and apical (rootward) portions of the teeth. In coronal crowding, there is a lack of space in the crown area of the tooth, whereas in apical crowding, the tooth necks are affected. An apical crowding is accompanied by a divergence of the tooth crowns, there may even be a gap formation coronally. In coronal crowding, the teeth are often interlocked, which makes it difficult to clean the interdental spaces.
Pathogenesis (disease development) – Etiology (causes)
Crowding is classified into primary, secondary and tertiary crowding depending on the cause. Primary crowding occurs whenever a mismatch between tooth and jaw size is the cause of the crowding. Secondary crowding occurs when premature loss of deciduous teeth causes the molars (molar teeth) to move mesially (forward), thus reducing the space available for the permanent teeth. Furthermore, tertiary crowding can occur, for example, due to late growth of the jaws or the eruption of wisdom teeth.
Consequential diseases
Pronounced crowding can make it more difficult to clean the interdental spaces, which can lead to an increased incidence of caries in the proximal area (interdental space). Likewise, a pronounced crowding of the teeth represents an aesthetic impairment for patients.
Diagnostics
Tooth crowding can be diagnosed on the basis of clinical findings and anamnesis. Supportive radiographs are obtained – orthopantomogram and cephalometric lateral radiograph. A teleradiographic lateral analysis can provide information on whether the jaw is too small. An impression and subsequent model analysis can be used to determine whether the tooth widths are normal or above average and whether the crowding is more coronal or apical.
Therapy
To eliminate crowding, there are several orthodontic options that can be considered, depending on the degree and cause of the crowding. To create more space for the permanent teeth, a jaw that is too narrow can be enlarged using a transverse expansion. This can be done by various both removable and fixed appliances. The simplest method is a so-called active plate. It is removable and has a screw with which the plate is widened slightly every day. Transpalatal arches, which run across the palate and are fixed to the upper molars, can also be used to widen the upper jaw. The quadhelix is a four-loop spring that can be activated by the orthodontist to also lead to an increase in width growth. In adult patients who still decide to undergo orthodontic treatment, maxillary expansion usually needs to be surgically supported. A second option for space acquisition is extraction (removal) of permanent teeth. This procedure is performed for both primary and secondary crowding. Orthodontic extraction therapy is also used as a compensatory extraction when individual teeth are not aligned.This therapy begins around the age of ten. In the context of extraction therapy, it is important to bear in mind that extraction also has consequences for the soft tissue profile and esthetics. Likewise, any growth still present must be taken into account so that the decision to perform an extraction is not made prematurely. Frequently, a premolar (small molar) is removed in each quadrant to create space. If space is needed more in the anterior region, the first premolar is usually extracted, whereas if there is a lack of space in the posterior region, extraction of the second premolar makes more sense. Sometimes the second molars (large molars) are also removed if wisdom teeth are in place and their eruption is thus made possible. A contraindication (counterindication) to extraction therapy exists in cases of deep bite and horizontal growth type.
