Determination of timing of functional and interceptive orthodontic treatment: A critical approach to growth indicators

Importance: Treatment timing of intervention for interceptive and functional treatments has been reported to be a critical issue in orthodontics when dealing with several types of malocclusions. Identification of the specific prepubertal, pubertal, and postpubertal growth phases, through the assessment of skeletal maturity, relies on the use of different growth indicators. These include the hand and wrist maturation (HWM), third finger middle phalanx maturation (MPM), cervical vertebral maturation (CVM), and dental maturation methods and others. Observations: Reliability of the different growth indicators in the identification of the circumpubertal growth phases varies according to the indicator and growth phase, whereas data on true diagnostic capability of these methods is still limited to the MPM and CVM methods. Generally, optimal treatment timing for maxillary transverse deficiency, palatally displaced canines and skeletal Class III malocclusion should be early, (i.e., pre-pubertal), whereas optimal (functional) treatment timing for skeletal Class II malocclusion should be late (i.e., pubertal). Growth indicators are better used in combination or chosen according to the type of growth phase/malocclusion to be treated, with dental maturation having the least clinical applicability. Moreover, for radiographic indicators, ossification events should to be preferred over the use of single stages. Conclusion: Although not all growth indicators proved to be fully reliable and in spite of the limitation of present evidence, the use of these growth indicators is recommended both in clinical practice and research.