A study on the changes of the soft tissue profile following orthodontic treatment by digital subtraction method

Cho, Won Tak; Yu, Dong Hwan

Abstract

The propose of this study was to quantify the changes of soft tissue profile following orthodontic treatment and to evaluate the relationship of those to the skeletal elements. Pre-and post-treatment lateral cephalometric head films of 40 cases(20 extraction cases, 20 non-extraction camas) were traced, and the changes following treatment were measured and quantified by digital subtraction method, and statisticall analyzed. The obtained results were as follows; 1. in extraction group, the change of upper lip area(UL) was 558.60+/-355.17 pixels, that of lower lip area(LL) was 941.15+/-364.07 pixels. But, in non-extraction group the change of uper lip area(UL) was 125.65+/-404.16 pixels, that of lower lip area(LL) was 104.05+/-440.93 pixels, which was significantly lesser than those in extraction group. 2. In extraction group, there was significant correlationship between upper lip area change(UL) and difference of upper incisor point(deltaUIP). Lower lip area change(LL) was significantly correlated with difference of upper incisor(deltaUIP), difference of Frankfort upper incisor angle(deltaFUIA) or difference of interincisal angle(deltaIIA). 3. In extraction group, the ratio of difference of upper incisor point(deltaUIP) to difference of labrale superius(deltaLS) was 1.68; difference of lower incisor point(deltaLIP) to difference of labrale inferius(deltaLI) was 1.19; difference of upper incisor point(deltaUlP) to increment in upper lip thickness(deltaTUL) was 1.95. 4. In non-extraction group, there was a significant cortelationship between upper lip area change(UL) and difference of upper incisor point(deltaUIP).