Soft tissue profile changes from 5 to 45 years of age

Abstract

The purpose of this study was to describe the changes in five soft tissue parameters that are commonly used by orthodontic practitioners in their diagnosis and treatment planning as well as in their evaluation of profile changes that occur with growth and orthodontic treatment. The subjects in this study were 20 males and 15 females for whom lateral cephalograms were available between 5 and 45 years of age. The parameters evaluated were two angles of facial convexity, the Holdaway soft tissue angle, and the relationship of the upper and lower lips to Rickett's esthetic line. Descriptive statistics for the absolute and incremental changes were collected on a yearly basis between 5 and 17 years of age as well as at early (25 years) and middle (45 years) adulthood. Growth profile curves were constructed for each parameter to describe the age-related changes in the five parameters for both males and females. The analysis of variance was used to compare the absolute and incremental changes both longitudinally and cross-sectionally. Significance was predetermined at P </=.05. The present findings indicated that (1) in general, the changes in males and females were similar in both magnitude and direction. On the other hand, the timing of the greatest changes in the soft tissue profile occurred earlier in females (10 to 15 years) than in males (15 to 25 years); (2) the angle of soft tissue convexity that excludes the nose expressed little change between 5 and 45 years; (3) the upper and lower lips became significantly more retruded in relation to the esthetic line between 15 and 25 years of age in both males and females; the same trends continued between 25 and 45 years of age; (4) the Holdaway soft tissue angle progressively decreased between 5 and 45 years of age. It is important for clinicians to be aware of these changes when planning the orthodontic treatment of the still growing adolescent patients because the changes might influence the extraction/nonextraction decision.