Diurnal variation in facial soft tissue profile: 3-Dimensional morphometry of facial soft tissue using laser scanner

Purpose The purpose of this study were to: (1) establish a facial soft tissue morphometric technique employing a 3-dimensional optical device; (2) evaluate its precision; and (3) determine the presence of diurnal variation in facial soft tissue morphology. Materials and methods Ten volunteers were enrolled using a 3-dimensional optical measuring device, SURFLACER VMH-300F. Measurements were conducted in the morning, during the daytime, and in the evening. Two analyses, reproducibility of measurement through comparison between the two measurements in each group (morning vs. morning, daytime vs. daytime, and evening vs. evening), and diurnal variation through inter-group comparison (morning vs. daytime, morning vs. evening, and daytime vs. evening) were carried out. Results The mean difference between two measurements in each group was 0.24 ± 0.06 mm in the morning group, 0.25 ± 0.08 mm in the daytime group, and 0.24 ± 0.06 mm in the evening group. As to diurnal variation, the difference was 0.38 ± 0.07 mm between the morning and daytime groups, 0.39 ± 0.03 mm between the morning and evening groups, and 0.40 ± 0.04 mm between the daytime and evening groups. Conclusions When facial morphology was measured at 3 different time points within a single day, the mean error was 0.24 ± 0.06 mm. Measurement at these 3 time points revealed no significant diurnal variation in facial soft tissue morphology. This technique and its results are anticipated to contribute to quantitative evaluation of facial soft tissue morphology.