How are lip prints collected, identified and compared in forensic cases?

1. C O L L E C T I O N ,
D E V E L O P M E N T ,
I D E N T I F I C A T I O N
A N D
C O M P A R I S O N O F
L I P P R I N T S
Muthuraj V
Volunteer of AFRS

2. C O N T E N T S
• Introduction
• Collection of lip prints
• Development of lip prints
• Identification of lip prints
• Comparison of lip prints
• Application and limitations
• conclusion

3. I N T R O D U C T I O N
• Lip prints, also known as cheiloscopy, are unique
patterns and characteristics found on the human lip
surface.
• They are considered a valuable tool in forensic
investigations for identification purposes.
• This presentation will discuss the processes involved
in the collection, development, identification, and
comparison of lip prints.

4. C O L L E C T I O N O F
L I P P R I N T S • Lip prints can be collected using various methods:
• Lipstick Method: In this method, a subject applies a
layer of lipstick or lip balm, then presses their lips
onto a clean white or transparent sheet of paper. The
lip prints left behind can be visualized and analyzed.
• Lip Gloss Method: Similar to the lipstick method, lip
gloss can be used instead of lipstick to create lip
prints on a clean surface.
• Lipstick Pad Method: A small pad or cushion soaked
in lipstick or lip gloss is pressed against the lips,
creating a clear impression that can be transferred
onto a piece of paper.

5. C O L L E C T I O N O F
L I P P R I N T S • Gelatin Method: A layer of gelatin is prepared by dissolving powdered
gelatin in water and allowing it to solidify. The subject presses their
lips onto the gelatin surface, leaving an impression that can be
analyzed
• Cellophane Tape Method: In this method, a piece of clear cellophane
tape is carefully pressed against the lips to lift the lip print. The tape is
then placed onto a white or transparent surface for analysis.
• Transparent Adhesive Method: A transparent adhesive sheet is applied
to the lips and pressed gently. When removed, the adhesive sheet
captures the lip print, which can be visualized and analyzed.
• Dental Impression Material Method: Dental impression materials, such
as alginate or silicone, can be used to create a mold of the lips. The
mold can then be filled with plaster or dental stone to obtain a three-
dimensional replica of the lip print.

6. D E V E L O P M E N T O F
L I P P R I N T S • Once lip prints are collected, they need to be
developed for analysis.
• Development methods include:
• Powder method: Powder is applied to the lip print
and gently brushed off, leaving the print
visible.Chemical method: Chemical substances, such
as ninhydrin or iodine fuming, can be used to
enhance the visibility of lip prints.
• Photography: Lip prints can be captured using
specialized photography techniques, such as infrared
or ultraviolet photography.

7. I D E N T I F I C AT I O N O F
L I P P R I N T S • The identification of lip prints involves comparing
the collected prints to known reference prints.
• Lip prints have distinct patterns, such as grooves,
furrows, and wrinkles, which can be classified into
different types based on their characteristics.
• Various lip print classification systems exist, such as
Tsuchihashi’s classification, Suzuki and
Tsuchihashi’s classification, or Santos’ classification.
• Computerized systems and software can aid in the
identification process by analyzing and matching lip
print characteristics.

8. C O M PA R I S O N O F L I P
P R I N T S
• When comparing lip prints, examiners look for
similarities and dissimilarities in the pattern and
features.
• Points of comparison include:
• Overall shape of the lip print.Presence of unique
features, such as scars, cuts, or deformities.
• Alignment and orientation of grooves and furrows.
• Comparison can be done visually or using automated
systems, depending on the available resources and
complexity of the case.

9. A P P L I C AT I O N A N D
L I M I TAT I O N S • Lip prints are used in various fields, including
forensic investigations, personal identification, and
criminal profiling.
• They can provide valuable evidence in cases where
other forms of identification, such as fingerprints,
are unavailable or inconclusive.
• However, there are certain limitations to
consider:Environmental factors and surface
conditions can affect the quality of lip prints.
• Individual variations and changes in lip features
over time can make identification challenging.
• Lack of standardized classification systems and
databases may hinder comparisons across different
cases.

10. F O R E N S I C A P P L I C AT I O N
O F L I P P R I N T S
• Identification and Individualization: Lip prints, like fingerprints, have unique characteristics
that can help identify and individualize individuals.
• Linking Suspects to Crime Scenes: Lip prints found at a crime scene can establish a
connection between a suspect and the location by comparing them to prints obtained from the
suspect.
• Evidence in Sexual Assault Cases: Lip prints can be crucial in sexual assault cases, as they
can help identify the perpetrator through analysis of lip marks on the victim or other surfaces
involved.
• Disputed Document Authentication: Lip prints can be used to authenticate documents, such
as wills, by comparing the lip print on the document to a known reference sample.
• Timeline Estimation and Suspect Elimination: Lip prints can assist in estimating the timeline
of events and eliminating suspects by comparing prints found at the scene with those of
potential suspects.

11. C O N C L U S I O N • Collection, development, identification, and
comparison of lip prints play a significant role in
forensic investigations and personal identification.
• Proper collection techniques and suitable
development methods are essential for obtaining
clear and reliable lip prints.
• Lip print patterns and characteristics can be
classified and compared to establish identification.
• Despite some limitations, lip prints offer valuable
insights and can be a valuable tool in forensic
science.

12. R E F E R E N C E
• Agarwal P, Bhatnagar G, Wadhwan V, et al. Lip prints: Role in forensic odontology. J Forensic
Dent Sci. 2012;4(2):93-96.
• Sharma P, Saxena S, Rathod V. Cheiloscopy: The study of lip prints in sex identification. J
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2012;4:47–52. [PMC free article] [PubMed] [Google Scholar]
• Reddy LV. Lip prints: An overview in forensic dentistry. J Adv Dent Res. 2011;1:17–20.
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13. THANK
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