Modified Angle's Classification for Primary Dentition
A cross-sectional investigation using new classification revealed various % Class ii and % Class iii molar relationships cases in preschool children. Angle's classification of malocclusion, however, is by far the most commonly used Excessive overjet and a Class II molar relationship are characteristics of a. Occlusion is defined as the contact relationship of the maxillary and mandibular teeth when Here is a tip to help you remember overjet: jets fly horizontally. The three classes according to Angle's classification are as follows: Class II malocclusion: The mesiobuccal cusp of the upper first molar occludes.
Edward Angle, who is considered the father of modern orthodontics, was the first to classify malocclusion. Angle believed that the anteroposterior dental base relationship could be assessed reliably from first permanent molar relationship, as its position remained constant following eruption.
According to Angle, the mesiobuccal cusp of the maxillary first molar aligns with the buccal groove of the mandibular first molar.
The maxillary canine occludes with the distal half of the mandibular canine and the mesial half of the mandibular first premolar. The teeth all fit on a line of occlusion which, in the upper arch, is a smooth curve through the central fossae of the posterior teeth and cingulum of the canines and incisors, and in the lower arch, is a smooth curve through the buccal cusps of the posterior teeth and incisal edges of the anterior teeth.
There is alignment of the teeth, normal overbite and overjet and coincident maxillary and mandibular midlines.
ANGLE’S CLASSIFICATION OF MALOCCLUSION | DENTODONTICS
The mesiobuccal cusp of the maxillary first permanent molar occludes with the mesiobuccal groove of the mandibular first permanent molar. In the mixed dentition, a classification of one-half cusp Class II flush terminal plane will develop into a Class I relationship in the permanent dentition.
The permanent premolars that replace the deciduous molars have a smaller mesio-distal dimension. This additional space in the mandible allows the permanent mandibular first molars to drift anteriorly to reach a Class I relationship.
Overjet is measured as the distance between the upper and lower incisors at the point of greatest severity. It is measured from the facial surface of the more lingual tooth usually the mandibular incisor and the incisal edge of the more facial incisor usually in the maxilla.
Zero mm of overjet indicates an edge-to-edge relationship. This is called a pseudo-Class III and may result in excess horizontal growth in those with remaining growth, leading to a more severe Class III skeletal relationship, abnormal wear of the incisors, and TMJ discomfort. Some deep bites result in impingement of the palate, which can lead to recession on the lingual of the incisors or palatal irritation from the pressure of the mandibular incisors.
Many times a patient presenting with deep bite will have accompanying pronounced curve of spee, decreased lower facial height, with or without an associated sagittal component of excessive overjet, all of which are indicative of potential severe problems. Determining whether the problem of deep bite is caused by extrusion of the maxillary anterior teeth or minimized eruption of the posterior teeth is important in planning treatment.
Most skeletal malocclusions can only be treated by orthognathic surgery. However, there are also other conditions, e. Many authors have tried to modify or replace Angle's classification. This has resulted in many subtypes and new systems see section below: Review of Angle's system of classes.
Angle's classification method[ edit ] Class I with severe crowding and labially erupted canines Class II molar relationship Edward Anglewho is considered the father of modern orthodontics, was the first to classify malocclusion. He based his classifications on the relative position of the maxillary first molar. The teeth should all fit on a line of occlusion which, in the upper arch, is a smooth curve through the central fossae of the posterior teeth and cingulum of the canines and incisors, and in the lower arch, is a smooth curve through the buccal cusps of the posterior teeth and incisal edges of the anterior teeth.
Any variations from this resulted in malocclusion types. It is also possible to have different classes of malocclusion on left and right sides. Neutrocclusion Here the molar relationship of the occlusion is normal or as described for the maxillary first molar, but the other teeth have problems like spacing, crowding, over or under eruption, etc.
Distocclusion retrognathismoverjet, overbite In this situation, the mesiobuccal cusp of the upper first molar is not aligned with the mesiobuccal groove of the lower first molar. Instead it is anterior to it. Usually the mesiobuccal cusp rests in between the first mandibular molars and second premolars.