Class III malocclusion includes those anomalies with the mesiobuccal cusp of maxillary first permanent molar occludes distal to the mesiobuccal grove of the mandibular first permanent molar.

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Aetiology Of Class III Malocclusions

• True class 3 malocclusions are due to underlying skeletal imbalance as a result of genetic basis:
  • Long mandible
  • Mandibular prognathism
  • Short/retrognathic maxilla
  • More retruded position of maxilla
• Narrow upper arch and broad lower arch: crowding seen more commonly and to a greater degree in the upper arch
• Habitual forward positioning of the mandible may occur as a result of occlusal prematurity’s or enlarged adenoids.
  • Retained primary dentition may deflect the eruption of successor teeth palatally into a crossbite
• Restrained maxillary growth following cleft lip and palate repair surgery.

Treatment Of Class III Malocclusions

1) No Treatment:

• If the patient has poor oral hygiene, a low IOTN, medical history contraindications, or if the patient declines treatment.

2) Upper Removable Appliances (URA):

• URA can be given to patients that are compliant and have good oral hygiene to tip teeth. Upper incisors can be proclined forward to correct the incisal relationship. Bite planes may be required to open the bite.

4) Fixed Appliance:

• Often the treatment of choice and allow 3D bodily movement of the tooth.
• Patients require excellent oral hygiene

5) Extractions:

• Extraction are usually combined with fixed appliances
  • Upper premolars usually used to create space

Moderate/Severe Cases:

• When orthodontic camouflage is not sufficient to correct the malocclusion Orthognathic surgery should be considered.
• Fixed appliances are usually used before and after surgery when orthognathic surgery is planned.

See also Median Diastema