It is possible to collect orthodontic anomalies under 2 main headings as skeletal anomalies and dental anomalies.
Skeletal orthodontic anomalies occur as a result of the deterioration of the relationship of the lower and upper jaw bones with each other and with the skull base.
Anteroposterior Skeletal Anomalies
Skeletal class I anomaly: In this anomaly, the position of the lower and upper jaws relative to each other is normal, while their position relative to the skull base is anterior or posterior. In addition, there may be combinations of various intra- and inter-jawed dental anomalies without any anomalies in the bony base.
Skeletal class II anomaly: In this anomaly, the lower jaw is posterior to the skull base or the upper jaw is anterior to the skull base, but it may also be a combination of the two conditions. Individuals have a convex profile.
Skeletal class III anomaly: In this anomaly, although the lower jaw is anterior to the skull base or the upper jaw is posterior to the skull base, both conditions may occur together. Individuals have a concave profile.
Skeletal Anomalies in Perpendicular Direction
Skeletal Deep Closure: In this anomaly, the vertical development of the jaws is insufficient and the lower third of the face appears shorter.
Skeletal Open Closure: In this anomaly, the vertical development of the jaws is excessive and the lower third of the face appears longer. In these cases, both anterior and lateral open bites can be seen, as well as anterior open bite. For example, in the case of closure, only the lower and upper second molars are in contact, and all other teeth may show an open bite.
Excess space (Diastema): If there is more than enough room in a dental arch for all the teeth to line up properly, gaps may form between the teeth. The gap between two adjacent teeth in a jaw is called a diastema. Diastema is most common between the upper central incisors. The reason for the diastemas formed in this region is mostly the long connective tissue attachment called the lip frenulum.
Strictness of Space (Crowdedness): If there is not enough room on the jawbone for all the teeth to line up properly, the teeth will line up in a cramped, crooked manner. Turning the teeth and eruptions in different positions can be seen. Anomalies Between the Jaws Here, there are abnormal relations between the lower and upper teeth, tooth groups or tooth arches.
Anteroposterior Anomalies (Angle Classification)
Angle Class I Anomaly (class I malocclusion): Angle class I anomalies have normal class I closure. Lack of space and excess space can be seen in the lower and upper tooth curves. Open bite in the vertical direction, lateral crossbite in the right-left (transversal) direction can be seen.
Angle Class II Anomaly (class II malocclusion): Compared to the normal bite (class I), if the lower occipital teeth are in a more backward position than the upper occipital teeth, it means that there is Angle class II occlusion. In Angle class II occlusion, the upper teeth are moved forward by one premolar width.
Angle Class III Anomaly (class III malocclusion): Compared to the normal bite (class I), if the upper occipital teeth are in a more backward position than the lower occipital teeth, it means Angle class III closure. In Angle class III bite, the lower teeth are moved forward by one premolar tooth width.
Open Closing: While the other teeth in the lower and upper jaws are in closing, some of the lower and upper teeth do not come into contact with each other and there is a gap of various sizes in the vertical direction between them is called open bite. Open bite can be seen in the anterior or lateral region. In anterior open bites, patients cannot bite.
Deep Closing: Unlike open bite, the upper teeth overly covered the lower teeth. The closure of the teeth in the anterior region may sometimes increase so much that the lower incisors may be in contact with the palatal mucosa. Accordingly, each time the jaw is closed, the lower incisors may cause irritation and injury to the anterior palate tissues.
Cross Closure: It can be seen in a single tooth in the anterior region, in groups of teeth and in the lateral region due to stenosis. It often negatively affects the development of the jaws.
Midline Mismatch: It is when the midline of the upper teeth and the midline of the lower teeth are not in the same plane. In general, malocclusion in the posterior region accompanies this.