[Cephalometric deciding factors in the early treatment of Class III malocclusion]

Many authors recommend early treatment for patients with Class III malocclusions in order to make their appearance more acceptable and also to re-channel the growth of basal bone into a normal pattern. However, the long-term effects and the stability of the results of this type of treatment have not been studied extensively. In the best interests of our patients, it would behoove us to know when early intervention is indicated and in what circumstances a strategy of watchful waiting and postponement of definitive treatment until the end of the growth period would be preferable. This retrospective study of a population of 30 patients from six to nine years old with skeletal and dental Class III malocclusions offers information on results obtained in early interceptive treatment, the potential for relapse, and the cephalometric criteria upon which a determination of the probable success or failure of treatment at this precocious stage can be made. A one-year treatment period began with rapid palatal expansion and was completed with alignment of the upper arch with a full-bonded appliance on the upper arch that was followed by orthopedic force delivered through an antero-posterior Delaire type facemask. In an evaluation eight years after the close of this early treatment, patients were separated into two groups, one of orthopedic success and the other of orthopedic failure. The inclination of the upper incisors proved to have descriptive value: the cases determined to be failures showed more inclination, a sign of early compensation. This meant that labio-version of upper incisors could be considered a predictive sign of relapse of an early treatment result. By means of a multiple regression analysis, we were able to discern three cephalometric components whose positive or negative readings would help to predict the probable prognosis for the success or failure of early treatment.