Impact of hyaluronic acid filler on lip impressions: a cheiloscopic study

Abstract

Objectives: The objective of this study was to evaluate, through cheiloscopic analysis, the impact of hyaluronic acid (HA) lip augmentation on lip impressions. Eleven patients underwent HA injections and had their lips analyzed for thickness, morphological classification, commissure position, and lip impression types at three time points: before treatment (T1), one month after (T2), and three months after (T3). Lip thickness was measured using a digital caliper, and commissure position was classified based on standardized digital photographs. For lip impression recording, lipstick was applied, and the lips were then pressed against a substrate. The types of lip grooves were determined after dividing the impression into eight quadrants. Data were statistically analyzed using repeated measures ANOVA and Fisher's exact test, with a significance level of 5 %.

Results: There was a significant increase in both upper and lower lip thickness, which remained stable after 3 months (p < 0,001). Regarding morphological classification, medium and mixed lips maintained their pattern in most cases, while thin lips became medium or mixed. No patient had "thick" or "very thick" lips after the treatment. There were also important changes in commissure position, particularly among patients with "lowered" commissures, which shifted to "horizontal." No variations in lip impressions were observed across the quadrants examined at any time point.

Conclusion: The findings of this study suggest that, for purposes of human identification, the pattern of lip impressions remains unchanged after HA lip augmentation.

Keywords: Dermal fillers; Hyaluronic acid; Legal dentistry; Lip prints.

Fig. 1

Schematic representation of the eight quadrants analyzed in the lip impression, numbered clockwise for cheiloscopic evaluation.

Fig. 2

Classification of labial groove patterns: (A) Type I – complete vertical lines; (B) Type I′ – incomplete vertical lines; (C) Type II – branched or bifurcated lines; (D) Type III – crossed lines; (E) Type IV – reticulated lines; (F) Type V – irregular or unclassifiable lines.

Fig. 3

Photographic documentation of 22 years female participant. Color images of the lips at rest: (A) baseline (T1), (B) 1 month after filler (T2), and (C) 3 months after filler (T3). Corresponding black and white images for enhanced contrast: (D) T1, (E) T2, (F) T3. Cheiloscopic lip impressions collected at each time point: (G) T1, (H) T2, (I) T3.

Fig. 4

Comparative analysis of labial groove classifications across the eight quadrants at the three evaluation time points (T1 – baseline, T2 – 1 month post-treatment, T3 – 3 months post-treatment).