The soft tissue cephalometric analysis, or STCA, has been advocated by Arnett et al2-3,4 as an aid for orthodontists and surgeons in treatment planning. It recommends analysis using a true vertical line (TVL) through subnasale, with natural head posture. It may also be used to quantify favorable or unfavorable change in the profile after overjet reduction, and hence has an important potential role in post-treatment analysis and in research. The STCA includes normal values for many aspects of facial profile and harmony, but in the following theoretical situations only seven of these will be considered (Fig. 7.1). For reasons of clarity, all other STCA values will be disregarded in this discussion, and it will be assumed that the upper- and mid- thirds of the facial profile are close to ideal, and that the upper incisors are well positioned.
Color codes used with the Arnett soft tissue cephalometric analysis
Black = within 1 SD Green = within 2 SD Blue = within 3 SD Red = more than 3 SD
Fig. 7.1 Only seven measurements from the STCA are included here. The upper incisor torque is measured relative to the maxillary occlusal plane and the lower incisor torque is measured relative to the mandibular occlusal plane. In this diagram, the following are projected to true vertical line (TVL): Soft tissue 'A' point, upper lip anterior, lower lip anterior, soft tissue 'B' point, and soft tissue pogonion. Black numbers are within 1 SD of normal.
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