Timing of early correction of mandibular hypoplasia in skeletal class II malocclusion: a review

Skeletal Class II malocclusion is a common malocclusion seen in clinics. It is characterized by maxillary protrusion and mandibular retrognathia and has a high incidence in adolescent mixed dentition and early permanent dentition. The early functional correction has achieved some clinical results in treating skeletal Class II malocclusion with mandibular hypoplasia. During treatment, the timing of correction is the key factor in determining the therapeutic effect, although it is difficult to understand. This review focuses on the timing of early correction of mandibular hypoplasia in combination with relevant assessment indicators and historical literature from four perspectives-the law of mandibular growth and development, the necessity of early treatment, the timing of early treatment, and the determination of the peak period of mandibular growth and development-to provide a theoretical reference for the timing of the treatment of clinical skeletal Class II malocclusion. This review shows that skeletal Class II mandibular growth has different characteristics in males and females. Bone growth assessment before treatment helps diagnose mandibular developmental morphology and the timing of early correction in adolescents with skeletal Class II malocclusion and hypoplasia of the mandible.