Class III in a growing adolescent whose mother wants to wait
14-year-old girl in late mixed dentition with a Class III skeletal pattern: ANB −2°, Wits −4 mm, mandibular plane 32°, upper incisors retroclined at 95°, lower incisors at 88°, 2 mm anterior crossbite and 3 mm negative overjet. She has 4 mm of upper crowding and 2 mm of lower crowding, and the second molars are erupting. Cervical vertebral maturation is stage CS3 and menarche has not yet occurred. She is concerned about her profile and does not want surgery. Her mother asks whether it would be better to wait until all the permanent teeth have erupted.
1. How do you answer the mother's question about waiting?
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Waiting is the wrong choice here, and the reason is growth timing.
- CS3 marks the pubertal growth spurt - the window in which maxillary protraction and orthopaedic change are most effective. Menarche has not occurred, so meaningful growth remains, but it is finite.
- If treatment is deferred until all permanent teeth have erupted, the pubertal peak may have passed and the skeletal component becomes much harder to influence; the options then narrow to camouflage or later orthognathic surgery, which she has already declined.
- However, timing is not the same as rushing. Before protraction, assess the transverse dimension: a narrow maxilla needs rapid palatal expansion first, then protraction. Eruption of the second molars does not need to be complete for this.
Explain to the mother that the crossbite also carries a risk of gingival recession and wear on the lower incisors, which is an independent reason not to wait.
2. Outline the treatment plan and the alternatives if growth modification is unsuccessful.
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First-line: orthopaedic correction
- RPE if transverse constriction is present, then a face mask delivering roughly 300–500 g per side for 12–16 hours a day over 6–9 months.
- Expect a modest skeletal effect (a few millimetres) combined with dental tipping; overcorrect where possible.
- Class III elastics or a functional appliance may supplement, depending on compliance.
If growth modification fails, or she is seen after the peak:
- Camouflage - procline upper incisors and retrocline lower incisors, with extractions if crowding demands. Trade-off: the profile may not improve, and lower incisors at 88° have limited retroclination reserve.
- Orthognathic surgery - the definitive option for a true skeletal discrepancy, but she has declined it; revisit at skeletal maturity if the discrepancy persists.
Key point: the lower incisor angle of 88° constrains how much camouflage is available; do not promise profile correction from dental movements alone.
3. What retention plan would you set, and why is it different from a routine Class I case?
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- Retention must resist relapse in both arches, and Class III correction relapses readily, especially with continued mandibular growth.
- Use a fixed lingual retainer on the lower anterior segment plus a removable maxillary retainer; consider a night-time removable retainer in the lower as backup.
- Continue review until growth cessation, not for the usual 12–24 months. Late mandibular growth can re-establish a negative overjet even after a good result.
- Overcorrect the overjet at the end of active treatment to allow for relapse.
- Document the growth status at each review so that any late deterioration is detected early and the orthognathic option can be reconsidered before skeletal maturity if needed.