Two-phase orthopaedic growth modification involves a phase 1 (early treatment) during pre-puberty followed by a phase 2 (comprehensive treatment) during peak mandibular growth at puberty.
Level of evidence: Moderate for specific use only (see indications) (Tulloch et al. 1997 & 2004, O’Brien et al. 2003 & 2009)
Suitable for ages: 9-11 years old
Indications: Class II skeletal malocclusion (mandible retrognathia, maxilla prognathism), Class II dental malocclusion, normal to deep bites, normal to hypodivergent skeletal patterns, psychosocial concerns, trauma risks
Contraindications: Dolichocephalic facial pattern, anterior open bites, downward backward rotated mandible (for some functional appliances), cases which can be delayed for a single phase treatment
Treatment Objectives and Biomechanics
- Orthopaedic advancement of mandible forward and downward
- Restraint of maxillary growth
- Early correction of Class II skeletal base with the potential correction of any relapse in the pubertal growth spurt
Appliances
- Functional appliances – Clark Twin Block, Herbst, Activator, Bionator etc.
- Headgears – maxillary restraint types, cervical pull etc.
