An estimate of craniofacial growth in Class III malocclusion.

OBJECTIVE

To provide an estimate of growth in Class III malocclusion by means of the analysis of a large population of males and females.

MATERIALS AND METHODS

The examined sample consisted of pretreatment lateral cephalometric records of 949 (492 females and 457 males) untreated Class III patients of Caucasian ancestry. Cephalometric dentoskeletal measurements at subsequent age periods in Class III subjects were compared with the population values from subjects included in the University of Michigan Growth Study (UMGS) at 11 consecutive age periods (from 6 through 16 years of age), in male and female groups separately.

RESULTS

No difference was found between the Class III and normal groups for the sagittal position of the maxilla at any of the age intervals examined. Sagittal mandibular position and dimensions in Class III subjects were consistently larger than in normal subjects, with the interval of largest "increase" in mandibular length occurring on average 1 year later in both female and male Class III subject with respect to subjects with normal occlusion.

CONCLUSIONS

Increases in mandibular length were substantially larger in Class III subjects than in subjects with normal occlusion even during the more mature age interval (15 to 16 years). Lower anterior facial height was significantly larger in Class III individuals during the late developmental stages.