Posttreatment changes in male and female patients: a comparative study.

The purpose of this study was to determine whether the posttreatment changes in patients with Class II, Division 1 malocclusions who were treated with either extraction or nonextraction express similar trends in the male and female patients. The material for this investigation was obtained from the records available in the Graduate Orthodontic Clinic at the University of Iowa. Ninety-one patients were treated for their Class II, Division 1 malocclusions, 44 subjects (21 males and 23 females) had four first premolar extractions and 47 subjects (20 males and 27 females) were treated with nonextraction. Matched normal subjects included 20 male and 15 female subjects for whom complete sets of data were available for the period of this study. None of these subjects had undergone orthodontic therapy. Thirty-nine cephalometric anteroposterior and vertical skeletal, dental, and soft tissue linear and angular measurements were derived. Twenty-four dental arch parameters were evaluated and included: overbite, overjet, maxillary and mandibular arch lengths, and arch widths, as well as tooth size-arch length discrepancies. Student t tests were used to compare male and female subjects for the following parameters: (1) absolute dimensions recorded before treatment, after treatment, and at retention; (2) the incremental changes between the various stages; (3) the relative posttreatment changes. The level of significance was predetermined at p < 0.05. From the current findings the following can be concluded: (1) There were significant differences in the size as well as the incremental changes of the various cephalometric dentofacial parameters between normal male and female subjects. (2) There were significant differences in the absolute posttreatment cephalometric changes between male and female subjects, particularly in linear dimensions. Similar, but less frequent, findings were observed in the relative posttreatment changes. (3) Significant differences in the posttreatment dental arch changes between male and female subjects were the least frequent. (4) Male and female subjects expressed similar statistical trends in the direction of posttreatment changes. Therefore clinicians should not expect to observe significant differences in the posttreatment trends on the basis of the gender of the patient. On the other hand, the changes in linear dimensions are larger in male than female subjects. Therefore, for a more accurate interpretation of growth and/or treatment changes, it is advisable to independently analyze data on male and female subjects.