Class III – detailed

➤ Reverse incisor overjet

• A young child should not be left in an edge-to-edge or reverse overjet position as it can distort maxillary growth. This is an indication for early treatment.

➤ Class III facial or skeletal pattern

• The maxilla’s peak growth occurs before the mandible. Maxilla deficient Class III skeletal bases can be protracted with early treatment to improve the facial and skeletal profile whilst reducing the need for surgery later (Mandell et al. 2016).

➤ Functional shift

• Mandibular functional shifts forward or laterally can result due to premature contact of the incisors. Such functional shifts can constrain maxillary growth and is an indication for early treatment.

➤ Any associated problems requiring treatment

• Class III maxilla deficiencies are often associated with transverse maxillary deficiencies as well. This can result in posterior crossbites and narrow palates. This is an indication for early treatment.

Aesthetic concerns of protrusive lower incisors

• Aesthetic concerns are not necessarily linked to the severity of the problem however they can be a significant social handicap. (Jolley et al. 2010, Meyer-Marcotty et al. 2010)

Reverse incisor overjet

• Whilst there is no strict reverse overjet threshold for treatment, the IOTN (Brook and Shaw 1989) has defined a mild need at an edge-to-edge bite, moderate need at > 1mm reverse overjet and severe need at > 3.5mm reverse overjet.

Speech or eating difficulties

• A reverse overjet can cause difficulties with speech and/or mastication and if present, it is often a chief concern to the patient.

Excessive dental wear

• An edge-to-edge bite or anterior crossbite can cause abnormal or pathologic dental wear.

Aesthetic concerns of the facial appearance

• A moderate to severe skeletal Class III can result in a concave facial appearance and prominent chin appearance that can be a psychological concern to the patient.

Any associated problems requiring treatment

• Crowding, spacing, anterior open bite, posterior crossbites etc.
• Treacher Collins syndrome, Crouzon’s syndrome etc.