2021 Volume 59 Issue 3 Pages 148-153
The purpose of this study was to develop a non-invasive, non-contact lip closure test. The orbicularis oris muscle, which acts on lip closure, is a facial muscle that is distributed on the facial skin. It is also called skin muscle. Therefore, it may be possible to quantitatively evaluate lip closure from the facial skin while the mouth is pursed. We devised a new method of taking a three-dimensional facial photograph during lip-pursing. A portable three-dimensional image capture device (VECTRA H1, Canfield, USA) was used for photography. Images were taken continuously from three directions : 45 degrees on the left side, 45 degrees on the front side, and 45 degrees on the right side, during both resting and lip-pursing. These images were combined into one three-dimensional facial image by software (VECTRA VAM ver. 6.5.4, Canfield, USA). Then, the superimposed images were analyzed by dividing them into two selected areas, the facial area and the lip area. As a result, in the facial area, the difference in surface area was 0.6 mm, the distance between images was －0.1 mm, and the sum of volumes was 1.5 cm3. In the lip region, the difference in surface area was 3.3 mm, the distance between images was 2.3 mm, and the sum of volumes was 3.4 cm3. In both cases, the lip area was larger than the facial area. We were able to quantify lip-pursing due to the activity of the orbicularis oris muscle, which is dominant in the lip area.
