Background: In scientific literature, numerous theories on the mechanism of facial aging can be found. The debate about facial sagging versus deflation is still ongoing. In this study, the metric changes in perioral soft tissue were demonstrated. These data can contribute to a better understanding of physical changes in the aging perioral area.

Methods: Upper lip measurements were performed on cranial magnetic resonance images of 200 Caucasian subjects (100 men and 100 women). The study population was aged between 20 to 30 and 65 to 80 years. The upper lip length and soft-tissue thickness were measured on sagittal and parasagittal section. Cross-section surface area of the upper lip was measured in the sagittal section to represent volume. The data were analyzed with a t test and results were considered significant at p < 0.01.

Results: The upper lip in the old age group differed significantly in length (19.24 percent in women and 18.24 percent in men), thickness (up to −40.55 percent in women and −32.74 percent in men), and volume (−20.89 percent in women and −17.40 percent in men). Soft-tissue thickness at the alar nasolabial fold was significantly thinner in the old age group (−25 percent in women and −25.7 percent in men) and showed significantly greater tissue loss than elsewhere in the upper lip (p < 0.001).

Conclusions: These results suggest that the aging perioral area is affected with a combination of soft-tissue lengthening, thinning, and volume loss. The clinical implications of this study on perioral rejuvenating strategies will be explained in part II.