Analysis of Age and Gender Using Lip Impression

Abstract

Lip prints are acquiring popularity in forensic science because they are unique, stable, and capable of providing personal identification. Human identification is on the rise in this new millennium because of rising crime, natural disasters, and terrorist attacks. Lip prints are a unique pattern comprising the sulci labiorum, or wrinkles and grooves on the labial mucus. I?agree that lip prints have uniqueness just like fingerprint and as such study of lip prints known as Cheiloscopy. Cheiloscopy is the study of the exterior portion?of the lip, which includes a multitude of ridges and indentations that can create a distinctive pattern known as a lip print. Each individual is like a fingerprint, with its own unique?features. This study examines the validity?of lip prints in determining their age and gender considering a sample of 300 individuals, divided equally within the jurisdiction of two age groups and both sexes. The analysis?of lip print patterns was performed in quadrants using Suzuki and Tsuchihashi classification, and chi-square, Pearson\'s correlation and regression analysis were applied to verify the results. A statistical analysis showed significant gender-related distributions, reporting significantly more Type I lip prints in women and more Type II?and Type IV lip prints in men (p=0.043). Age effects included: patterns of change?among young and old

Introduction

Overview

Cheiloscopy is the forensic study of lip prints, which are formed by grooves and wrinkles (sulci labiorum) on the lips. Like fingerprints, lip prints are unique to each individual and can serve as a reliable tool for human identification, especially in cases of crimes, disasters, or missing persons. Lip prints can be left as trace evidence at crime scenes and are unaffected by age or minor injuries.

Classification

The Suzuki and Tsuchihashi classification (1970) categorizes lip prints into five types:

• Type I – Complete vertical grooves

• Type I′ – Incomplete vertical grooves

• Type II – Branched grooves

• Type III – Intersected grooves

• Type IV – Reticular patterns

• Type V – Undetermined

Study Design

• Type: Cross-sectional observational study

• Sample Size: 300 individuals (150 males, 150 females)

• Age Groups:

  • Group 1: Ages 15–25

  • Group 2: Ages 26–70

• Method: Lipstick application, transfer to cellophane tape, mounted on white paper, then analyzed under magnification.

Data Analysis

• Software: IBM SPSS

• Tests Used: Descriptive statistics, Chi-square, Pearson correlation, and Independent T-test

• Criteria: Participants were healthy and provided consent; those with lip injuries or deformities were excluded.

Results

Group 1 (Ages 15–25)

• Most common lip print: Type I (37.3%)

• Distribution:

  • Males: 36.0% Type I

  • Females: 38.3% Type I

• Other types (descending frequency): II, III, IV, V

Group 2 (Ages 26–70)

• Most common lip print: Type I (51.3%)

• Distribution:

  • Males: 28.0% Type I

  • Females: 23.3% Type I

• Other types (descending frequency): II, III, IV, V

Statistical Findings

• Independent T-test showed no statistically significant difference in lip print types between genders (p > 0.05), indicating lip prints are not gender-specific.

Conclusion

This study has drastically pertained the domain of?forensic cheiloscopy to lineate lip print patterns with age and sex to an extent that is statistically significant. It was statistically verified (regression analysis and chi-square tests) how much lip prints could be used for the identification of someone, especially when other biometric data are?not available. The study also addresses the challenges posed by environmental factors, as well as calls?for standardization in lip print collection and analysis. These findings are instructive and help advance the study,?providing a baseline for future studies and stimulating development of globally applicable, well-established methodologies. The results further indicate that future integration of digital technologies, such as AI and machine learning, may enhance the accuracy and efficiency of lip print analysis. This study supports the continued applicability of conventional biometric instruments, such as lip prints, as forensic science advances, providing an affordable option in environments with limited resources and broadening the range of forensic identification techniques. In a nutshell, the study shows how cheiloscopy can revolutionize the field of forensic science by linking theoretical knowledge with real-world applications.

References

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Copyright

Copyright © 2025 Yashaswini R, Praveen N. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.