Misalignment is a misalignment or misalignment between teeth when they come close to each other. The term was put forward by Edward Angle as a derivative of occlusion. Malocclusion (mal+occlusion=misocclusion) refers to the way opposing teeth meet.
Signs and symptoms
Malocclusion is common, although usually not severe enough. Those with more severe malocclusions that are present as part of craniofacial abnormalities may require orthodontic and sometimes surgical treatment to correct the deformity. Correction can reduce the risk of tooth decay and relieve pressure on the mandibular joint. Orthodontic intervention is also used for aesthetic reasons.
Skeletal disharmony often distorts the shape of the patient's face. They seriously affect the aesthetic component of the face and can be combined with chewing or speech problems. Most skeletal bites can only be treated with orthognathic surgery.
Classification
Depending on the sagittalTooth-to-jaw ratios, occlusion can be classified mainly into three types according to Angle's occlusion class system published at the end of the 19th century. There are other reasons, for example, crowding of the teeth, which does not directly fit into these types of malocclusion.
Many authors have tried to replace Angle's classification. This has led to many subtypes and new systems.
A deep bite (also known as a Type II bite) is a condition in which the upper teeth overlap the lower teeth, which can result in hard and soft tissue injury and appearance. The bottom type has been found in 15-20% of the US population.
Open bite - a condition characterized by a complete lack of overlap and occlusion between the upper and lower incisors. In children, open bite can be caused by prolonged thumb sucking. Patients often present with speech and chewing disorders.
Angle classes, orthodontics
Edward Angle was the first to classify malocclusion. He based his systematizations on the relative position of the maxillary first molar. According to Angle, the mesiobuccal point of the maxillary first molar must match the buccal groove of the mandibular first molar. All teeth must correspond to the line of occlusion, which is a smooth bend in the upper arch through the central fossa of the posterior teeth and the cingulate bone of the canines and incisors, and in the lower arch - a smooth bend through the sharp projections of the posterior teeth and the incisal edges of the anterior teeth. Any deviations from this led to types of malocclusion. There are also cases of different classesmalocclusion on the left and right sides. There are three Angle classes for canines and molars.
Class I
Neutrocclusion. Here the molar ratio is acceptable or as described for the maxillary first molar, but other teeth have problems such as spacing, crowding, over or under eruption, etc.
Class II
Distocclusion (retrognathism, overjet, overbite).
In this situation, it is observed that the mesiobuccal point of the upper first molar does not coincide with the mesiobuccal groove of the lower first molar. The mesiobuccal cusp usually lies between the first mandibular molars and the second premolars. There are two subtypes:
- Section 1: molar relationships are the same as class II and the front teeth are protruding.
- Section 2: Molar ratios are the same as Class II, but the anterior teeth are retroclined and the posterior teeth appear to overlap the anterior teeth.
Class III
Mesiocclusion (prognathism, anterior crossbite, negative g-force, underbite). In this case, the upper molars are located not in the mesiobuccal sulcus, but behind it. The mesiobuccal point of the maxillary first molar lies posterior to the mesiobuccal groove of the mandibular first molar. The lower front teeth are more prominent than the upper front teeth. In this case, the patient very often has a large lower jaw or a shortmaxillary bone.
Overview of alternative systems
The main disadvantage of classifying malocclusions according to Angle's grading system is that it only considers 2D axial view in the sagittal plane at occlusion if the occlusion problems are 3D. Other deviations in the spatial axes, functional deficiencies and other therapy-related features are not recognized. Another disadvantage is the lack of a theoretical justification for this descriptive class system. Among the weak points discussed is the fact that it does not take into account the development (etiology) of bite problems and does not pay attention to the proportions of the teeth and face. Thus, numerous attempts have been made to modify the Angle class system or replace it entirely with a more efficient one. But she continues to lead mainly because of her simplicity and conciseness.
Known modifications of Angle's classification date back to Martin Dewey (1915) and Benno Lischer (1912, 1933). Also, alternative classifications were proposed among others by Simon (1930, first three-dimensional classification system), Jacob A. Salzmann (1950, with a classification system based on skeletal structures) and James L. Ackerman and William Profit (1969).
