Physiologic timing of orthodontic treatment.

1. With the knowledge that certain facial bones respond in growth similarly to the growth of long bones, the hand-wrist film can be used as an indicator of the maturational status of the orthodontic patient. 2. Six stages of hand-wrist development have been advocated as guides in the timing of treatment with the stages geared to the individual patient rather than to statistical tables. 3. Stage 2 represented the important early prepubertal period when much growth was ignored but during which Class II correction could be effectively achieved without prolonged periods of mechanotherapy. 4. It was emphasized that the puberal growth spurt could be overlooked by the clinician. In addition, puberal spurt in the female may be of such a short duration that much growth may have already elapsed by the time this stage was recognized. 5. Stage 5 represented the period of residual growth during which posttreatment changes could occur. At the present state of the art these changes seem to be unpredictable but some warning may be possible with the use of the hand-wrist film taken prior to the termination of treatment. 6. The clinician is encouraged to utilize the hand-wrist film as another diagnostic aid. A few easily recognizable events can indicate the individual's maturational status.