Growth changes in the soft tissue facial profile.

Longitudinal growth changes in the soft tissue profile of 40 caucasians between the ages of 7 and 18 were studied. The sample consisted of 17 males and 23 females who had Class I dentitions and balanced faces at age 7 and 18 years. None of the subjects received any orthodontic treatment. Cephalometric radiographs were available, as a rule, on a yearly basis. Soft tissue thickness, measured at the nose, upper lip, lower lip and chin, as well as the length of the upper and lower lip, all increased by varying amounts over the period of the study. Females acquired more growth as a percentage of their adult size (at age 18) than males in all variables except the angle of inclination of the skeletal chin which increased more in males. The largest increase in relative size was noted in the nose measurements. In males, the nose had not attained adult size even at age 18. Upper lip length growth, on the other hand, in both males and females was complete by the 15th year. The difference between male and female lip length growth was clinically significant; the average aggregate increase in upper and lower lips combined in males was 6.9 millimeters compared to 2.65 millimeters in females. The total gain in thickness at laberale superius was over four times as much in males as in females and continued to increase in males even at age 18. The change in thickness of the soft tissue at pogonion was not large, an average of 2.4 millimeters in males and 1.5 millimeters in females. The major contribution to the anterior growth of the chin was translatory, contributed largely by growth in the skeletal length from pogonion to pterygomaxillary plane.