Year : 2009 | Volume
: 20 | Issue : 4 | Page : 453--457
Comparative reliability of cheiloscopy and palatoscopy in human identification
Preeti Sharma, Susmita Saxena, Vanita Rathod
Department of Oral Pathology and Microbiology, Subharti Dental College, Meerut (UP), India
Department of Oral Pathology and Microbiology, Subharti Dental College, Meerut (UP)
Background: Establishing a person«SQ»s identity in postmortem scenarios can be a very difficult process. Dental records, fingerprint and DNA comparisons are probably the most common techniques used in this context, allowing fast and reliable identification processes. However, under certain circumstances they cannot always be used; sometimes it is necessary to apply different and less known techniques. In forensic identification, lip prints and palatal rugae patterns can lead us to important information and help in a person«SQ»s identification. This study aims to ascertain the use of lip prints and palatal rugae pattern in identification and sex differentiation.
Materials and Methods: A total of 100 subjects, 50 males and 50 females were selected from among the students of Subharti Dental College, Meerut. The materials used to record lip prints were lipstick, bond paper, cellophane tape, a brush for applying the lipstick, and a magnifying lens. To study palatal rugae, alginate impressions were taken and the dental casts analyzed for their various patterns.
Results: Statistical analysis (applying Z-test for proportion) showed significant difference for type I, I«SQ», IV and V lip patterns (P < 0.05) in males and females, while no significant difference was observed for the same in the palatal rugae patterns (P > 0.05).
Conclusion: This study not only showed that palatal rugae and lip prints are unique to an individual, but also that lip prints is more reliable for recognition of the sex of an individual.
|How to cite this article:|
Sharma P, Saxena S, Rathod V. Comparative reliability of cheiloscopy and palatoscopy in human identification.Indian J Dent Res 2009;20:453-457
|How to cite this URL:|
Sharma P, Saxena S, Rathod V. Comparative reliability of cheiloscopy and palatoscopy in human identification. Indian J Dent Res [serial online] 2009 [cited 2020 Aug 10 ];20:453-457
Available from: http://www.ijdr.in/text.asp?2009/20/4/453/59451
Human identification is one of the most challenging subjects that man has been confronted with. Human identification is based on scientific principles, mainly involving dental records, fingerprints and DNA comparisons. Sometimes, it becomes necessary to apply lesser known and unusual techniques like cheiloscopy and palatoscopy. ,
The theory of uniqueness is a strong point used in the analysis of fingerprints and bite marks to convince the court of law. Likewise, even lip prints and palatal rugae patterns are considered to be unique to an individual and hence hold the potential for identification. The wrinkles and grooves on the labial mucosa (called sulci labiorum) form a characteristic pattern called "lip prints," the study of which is referred to as cheiloscopy. , This is considered unique to an individual and analogous to fingerprints. Palatal rugae are irregular, asymmetric ridges of the mucous membrane extending laterally from the incisive papilla and the anterior part of the median palatal raphe. Rugoscopy, the study of palatal rugae, finds application in the field of anthropology, comparative anatomy, genetics, forensic odontology, prosthodontics and orthodontics. , Encouraged by the results of our previous study on lip prints,  we added another parameter of palatal rugae patterns to assess sex differences in the present study. The main objective of this study was to ascertain the use of lip prints and palatal rugae pattern in identification and sex differentiation.
Materials and Methods
A total of 100 subjects, 50 males and 50 females were selected, their ages ranging between 20-30 years. All subjects were healthy individuals free of congenital abnormalities, inflammation, trauma or orthodontic treatment.
Care was taken to select individuals with no lesions on the lips. Individuals with known hypersensitivity to lipsticks were not included in the study. A dark coloured lipstick was applied with a single stroke, evenly on the vermilion border. The subjects were asked to rub both the lips to evenly spread the applied lipstick. After about two minutes, a lip impression was made on a strip of cellophane tape on the glued portion, which was then stuck on to a white bond paper. This served as a permanent record. The impression was subsequently visualized with the use of a magnifying lens. The number of lines and furrows present, their length, branching and combinations were noted. The lip prints obtained were coded, while noting the name and sex of the respective individuals. At the time of analysis the sex of the print was not disclosed.
In this study, we followed the classification of patterns of the lines on the lips proposed by Tsuchihashi. 
Type 1 : Clear-cut vertical grooves that run across the entire lips
Type 1′ : Similar to type 1, but do not cover the entire lip
Type 2 : Branched grooves
Type 3 : Intersected grooves
Type 4 : Reticular grooves
Type 5 : Grooves do not fall into any of the type 1-4 and cannot be differentiated morphologically (undetermined).
For classification, the middle part of the lower lip (10 mm wide) was taken as study area in accordance with Sivapathasundaram et al.  Since this fragment is almost always visible in any trace, the determination of the pattern depends on numerical superiority of properties of the lines on this study area. The sex of the individual was determined as per the descriptions given by Vahanwala et al. ,
Type 1, 1′ : Pattern dominant - Female
Type 2 : Patterns are dominant - Female
Type 3 : Pattern present - Male
Type 4 : Male
Type 5 : (varied patterns) - Male
Same patterns in all quadrants - Female
The results obtained were verified from the coded data collected at the beginning of the study.
To record palatal rugae, alginate impressions of the maxillary arch was made and poured with dental stone. A dental plaster base was made and casts were preserved for interpretation. The outline of the rugae was traced on these casts using a sharp graphite pencil under adequate light [Figure 1]. The palatal rugae pattern were then analyzed on these casts with the help of magnifying lens, using the classification by Lysell. 
The rugae pattern was classified based on their length, shape, direction, and unification.
(A) The rugae were classified based on their length as: 
Primary: - 5 mm or more
Secondary: - 3 to 5 mm
Fragmentary: - 2 to 3 mm
Rugae less than 2 mm were disregarded. A ruga's length was determined by measuring its greatest dimension regardless of its shape.
(B) The rugae were divided into four types based on their shape as: [Figure 1]
Curved: They had a crescent shape and curved gently. Evidence of even the slightest bend at the origin or termination of a ruga led to it being classified as a curved ruga.
Wavy: If there was a slight curve at the origin or termination of a curved ruga, it was classified as wavy.
Straight: They ran directly from their origin to termination.
Circular: Rugae that formed a definite continuous ring.
(C) The direction of the ruga was determined by measuring the angle formed by the line joining its origin and termination and the line perpendicular to the median raphae. Forwardly directed rugae were associated with positive angles, backwardly directed rugae were associated with negative angles and perpendicular rugae were associated with zero angles.
(D) Unification occurs when two rugae are joined at their origin or termination. Rugae were considered diverging if two rugae had the same origin but immediately branched. Rugae with different origins, which joined on their lateral portions, were considered converging. Rugae were tested for gender and for both sides of the palate using the following parameters:
Total number of rugaeNumber of primary rugaePredominant shapePredominant directionUnification of rugae
The examination of lip print pattern revealed the following observations:
No two lip prints matched with each other, thus establishing the uniqueness of the lip prints.Type 1, 1′ were most commonly seen in females whereas type 4 and 5 were seen most commonly in males [Figure 2].Forty four females were correctly recognized as females and forty five males were correctly identified as males on the basis of their lip prints [Figure 3] and [Figure 4].The total number of rugae and number of primary rugae were found to be more in females than in males. The predominant shape in males was wavy and curved followed by the straight pattern. The ring or circular shape was rare and seen only in five females; in the females, the wavy shape was predominantly seen followed by curved and straight shapes. No significant difference was found in the unification of rugae between males and females, a significant difference was observed for the direction of palatal rugae.
The Z-test (standard normal variate test) for proportion, to test the significant difference between males and females for different types of lip print patterns, showed a significant difference for 1, 1′, 4 and 5 types (P 0.05) [Table 2].
In the field of forensic odontology, cheiloscopy and rugoscopy are still in their infancy. Cheiloscopy is applicable mostly in identifying the living, since lip prints are usually left at crime scenes, and can provide a direct link to the suspect. ,, In recent years, lipsticks that do not leave any visible trace after contact with surfaces such as glass, clothing, cutlery, or cigarette butts have been developed.  These lip prints are characterized by their permanence and are, therefore, referred to as "persistent" lip prints. Although invisible, these prints can be "lifted" using materials such as aluminium powder and magnetic powder. , The edges of the lips have sebaceous glands, with sweat glands in between. Thus, secretions of oil and moisture from these enable development of "latent" lip prints, analogous to latent finger-prints. , Although lip prints have previously been used in a court of law, the use is not consensual and some authors believe further evidence is needed to confirm their uniqueness. 
Palatal rugae, in addition to being unique to an individual, are protected from trauma by their internal position in the head and insulated from heat by the tongue and buccal fat pads, unlike fingerprints that can get destroyed. Once formed, they do not undergo any changes except in length, due to normal growth, remaining in the same position throughout an entire person's life. Even diseases, chemical aggression or trauma do not seem to be able to change the palatal rugae form. ,
Contrary to lip prints, palatoscopy might not be so useful in crime scene investigation in the linking of suspects to the crime scene. In fact, this kind of evidence is not expected to be found in such circumstances. On the other hand, palatoscopy may be used as a necroidentification technique. It is the most valuable technique in aeronautical accidents in order to ensure identification of pilots making use of ante mortem data. 
Lip prints were first described by Fisher in 1902,  however, it was only in1930 that de Lille  developed some studies which led to lip print use in criminology. Thomas and van Wyk,  have mentioned that it was Edmond Locard, one of France's greatest criminologists, who recommended the use of lip prints in human identification. Snyder  in his book 'Homicide Investigation,' written as early as 1950, mentions the possible use of lip prints in the identification of individuals. Suzuki and Tsuchihashi  proposed a classification dividing the pattern of grooves on the lip into six types and also named the wrinkles and groove visible on lips as 'sulci labiorum rubrorum'.
Caldas et al.  and Shetty et al.  have reported that palatal rugae were first described by Winslow in 1753; however, Kuppler, in 1897, was the first person to study palatal anatomy to identify racial anatomic features. They have also cited in their article that palatal rugoscopy was first proposed in 1932 by a Spanish investigator named Trobo Hermisa. In 1937, Carrea developed a detailed study and established a way to classify palatal rugae, , however according to several authors, ,, Lysell,  developed the first classification system for palatal rugae pairs. Thomas and Kotze, ,, in their study, had visualized the problems in classifying and interpreting the endless detailed variations found in palatal rugae. They also acknowledged the need to standardize the classification system. However, they observed that it was difficult to formulate a universally acceptable classification and conceived that "a single operator alone (eliminating inter-observer error) and considering his own classification can successfully apply in a comparative project and that the results derived from the comparisons are of greater value than the classification itself "  (cited in Nayak et al.  ). Palatal rugae have been studied for various reasons, the most important one being personal identification in the field of forensic odontology. ,,,
In the present study, we aimed to find out the variations in lip patterns of 100 individuals. We tried to ascertain whether the lip-prints hold the potential for determination of sex of the individual from their configuration. Even though the lines and furrows are present, both in the upper and lower lip from one corner of the mouth to the other corner, only the middle portion in the lip is taken into account, since this portion is always visible in any trace.  We labeled a particular pattern on the basis of numerical superiority of types of lines present, that is, vertical, intersected, branched or reticular. If more than one pattern predominates it is typed as undetermined.
In the past, some researchers have worked on lip prints to prove that a gender difference does exist in lip print. According to a study by Vahanwala et al.  type 1 and type 1′ patterns were found to be dominant in females while type 3 and type 4 patterns were dominant in males. In another study by Vahanwala and Parekh,  it was shown that all four quadrants with the same type of lip prints were predominantly seen in female subjects and male subjects showed the presence of different patterns in a single individual. We also found type 1 and type 1′ patterns to be dominant in females while type 4 and type 5 patterns were dominant in males, reinforcing previous observations. ,
In addition, we observed that no lip prints matched with each other and that lip print pattern was unique to every individual. While analyzing palatal rugae patterns, no significant difference was found in the total number of rugae in males and females. While the wavy shape was more common in females, curved shape was more commonly seen in males. Also, no particular characteristic pattern of rugae was observed in either sex. However, it was established beyond doubt that palatal rugae are unique to an individual.
Studies conducted by English et al.  and El-Fotoh et al.  proved that rugae pattern was absolutely unique to an individual and could be used for identification.  Differences between genders using palatoscopy have been studied without any conclusions. ,, Differences in the shape of the palatal rugae in different races and population have been investigated but no significant sex differences were observed in those studies either. ,,
Identification of living or dead people is often a difficult, challenging and time-consuming process. There is no doubt that both cheiloscopy and palatoscopy are unique to an individual, thus their use in forensic identification is fairly justified. Both cheiloscopy and rugoscopy are rather simple techniques not requiring any complex instrumentation.  While cheiloscopy is useful to identify the living; palatoscopy has been successfully used in necroidentification. The present study proves that both cheiloscopy and rugoscopy have the potential to identify an individual; also lip prints are more reliable in identifying the sex of an individual as compared to palatal rugae patterns. Thus, lip prints and palatal rugae hold potential as a supplementary tool, along with the dentition, to establish the identity of an individual. Nevertheless, we believe that larger samples should be examined in detail to further validate the findings of this study and come to definitive conclusions.
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