Malocclusion can present itself in numerous ways. Classification involves the grouping together of various malocclusion into simpler or smaller groups. In order to have a system of classification, standards should be set up that represent normalcy. The deviations from the accepted norms should also be grouped into various smaller divisions or categories.
The advantages of classifying malocclusion is as follows:
a. Classification helps in diagnosis and planning treatment for the patient.
b. Classification helps in visualizing and understanding the problem associated with that malocclusion.
c. Classification helps in communicating the problem.
d. Comparison of the various malocch4sions is made easy by classification.
Types of Malocclusions
Malocclusion can be broadly divided into:
i) Individual teeth malposition or intraarch malocclusion
ii Malrelation of dental arches to one another upon bony bases which may themselves be normally related
iii) Skeletalmalocclusions which involve the underlying bony bases
Individual Teeth Malpositions
A tooth can be abnormally related to its neighboring teeth. Such abnormal variations are called individual teeth malposition or intra-arch malocclusion. The individual teeth malposition can be teeth abnormal inclination (or tipping) of the teeth or abnormal displacements.
Abnormal inclination involves the abnormal tilting of the crown, with the root being in normal position. Bodily displacement involves abnormal location of the crown as well as the root in the same direction. Some of the commonly seen individual teeth malpositions are:
Distal inclination or distal tipping (Fig A): This refers to a condition where the crown of the tooth is tilted or inclined distally.
Mesial inclination or mesial tipping (Fig B): This is a condition where the crown of the tooth is tilted or inclined mesially.
Lingual inclination or lingual tipping (Fig C): This is an abnormal lingal or palatal tilting of the tooth. This condition is also called retroclination.
Buccal inclination or buccal tipping (Fig D): This refers to labial (in case of anterior) or buccal (in case of posterior) of the tooth.This condition is also called proclination.
Mesial displacement (Fig E): This refers to a tooth that is bodily moved in a mesial direction towards the mid line.
Distal displacement (Fig F): This refers to a tooth that is bodily moved in a distal direction away from the mid line.
Lingual displacement (Fig G): This is a condition where the entire tooth is displaced in a lingual direction.
Buccal displacement (Fig H): This describes a condition where the tooth is displaced bodily in a labial or buccal direction.
Infraversion or infra- occlusion (Fig I) : The terms infraversion or infra-occlusion refer to a tooth that has not erupted enough compared to the other teeth in the arch.
Supraversion or supra- occlusion (Fig J): This is a tooth that has over-erupted as compared to other teeth in the arch. It is also called supra-occlusion.
Rotations (Fig K): This term refers to tooth movements around its long axis.
Disto- lingual or mesio-buccal rotation: This describes a tooth which has moved around its long axis so that the distal aspect is more lingually placed.
Mesio- lingual or disto- buccal rotation: This is a condition where the tooth has rotated around its long axis so that the mesial aspect is more lingually placed.
Transposition (Fig L): This term describes a condition where two teeth have exchanged places.
Malrelation of Dental Arches
These malocclusion are characterized by abnormal relationship between two teeth or groups of teeth of one arch to the other arch. These inter-arch malocclusion can occur in the sagittal, vertical or in the transverse planes of space.
Sagittal plane malocclusion
Pre-normaL Occlusion: This term refers to a condition where the lower arch is more forwardly placed when the patient bites in centric occlusion.
Post-normal occlusion : This is a condition where the lower arch is more distally placed when the patient bites in centric occlusion.
Vertical plane malocclusion
Deep bite or increased overbite: This refers to a condition where there is an excessive vertical overlap between the upper and lower anterior teeth.
Open bite : This is a condition where there is no vertical overlap between the upper and lower teeth. Thus a space may exist between the upper and lower teeth when the patient bites in centric occlusion. The open bite can be in the anterior or the posterior region.
Transverse plane malocclusion
The transverse plane inter-arch malocclusion includes various types of cross bites. The term cross bite refers to abnormal transverse relationship between the upper and lower arches.
They are malocclusion caused due to defects in the maxilla or mandible. The defects can be in size, Position or Relationship between the jaws.