|Year : 2015 | Volume
| Issue : 3 | Page : 393-398
Palatal Rugoscopy: A new era for forensic identification
Namrata Harchandani1, Swati Marathe2, Rahul Rochani1, Shams Ul Nisa2
1 Private Practitioners, Bhopal, Madhya Pradesh, India
2 Department of Oral Medicine and Radiology, Bharati Vidyapeeth Deemed University Dental College and Hospital, Pune, Maharashtra, India
|Date of Submission||09-Apr-2015|
|Date of Acceptance||02-Nov-2015|
|Date of Web Publication||25-Nov-2015|
C/O Dr. Rahul Rochani, House No. 18, Akshadha Niket, Chunna Batti, Bhopal - 462 017, Madhya Pradesh
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Aims and Objectives: To observe and compare the distribution of various palatal rugae patterns in western and northern Indian populations and to study the variations in male and female subjects respectively. Materials and Methods: The study consisted of 100 subjects, 50 each from the two groups of geographically different regions of western and northern India. After obtaining informed consent, an alginate impression of maxillary arch was made for interpretation. The number, type, and unification were followed according to Thomas and Kotze's classification and the shape was recorded according to Kapali et al.'s classification. Results: The shape of rugae was compared between the two study groups and was found to be highly significant between western Indian and northern Indian subjects. The number and shape of rugae differed significantly between the genders, with males having a highly significant difference as compared to the females. The western Indian group showed wavy shape predominantly in males and females had straight rugae. Similarly, the northern Indian male participants also had wavy shape; however, females in this group had more curved shaped rugae. Conclusion: The uniqueness of palatal rugae pattern can be utilized similar to fingerprints and when combined with other methods, it can help in the identification of a person.
Keywords: Forensic Odontology, palatal rugae, unification
|How to cite this article:|
Harchandani N, Marathe S, Rochani R, Nisa SU. Palatal Rugoscopy: A new era for forensic identification. J Indian Acad Oral Med Radiol 2015;27:393-8
|How to cite this URL:|
Harchandani N, Marathe S, Rochani R, Nisa SU. Palatal Rugoscopy: A new era for forensic identification. J Indian Acad Oral Med Radiol [serial online] 2015 [cited 2020 Jul 8];27:393-8. Available from: http://www.jiaomr.in/text.asp?2015/27/3/393/170469
| Introduction|| |
In this world of simulation, the identity of any individual is always questionable in situations of mass massacres and disasters. The professional obligation of a dental surgeon to mankind is not only to serve in diagnosis and treatment of orofacial diseases, but also to serve in determining a person's identity at the scene of crime and disasters with the support of these unique orofacial tissues. A lot of literature is available on forensic odontology tools, but still this branch of odontology is in its infancy stage in India. In the present article, the researcher has tried to evaluate palatal rugae. The study of palatine rugae patterns (rugoscopy) in different populations would not only help in identification of an individual, but also aid in gender determination in criminal investigations, natural and man-made disasters, and mass massacres. , In today's brutal world where soft tissue damage is not uncommon, rugoscopy may aid in the necro identification technique of decomposed bodies. The palatal rugae are like fingerprints that do not change during the life of an individual. Palatine rugae are unique and are reasonably stable during the lifetime of an individual. , The present study aims to determine palatal rugae in two different populations of western and northern India. The study was performed to observe and compare the distribution of various palatal rugae in terms of their number, type, unification, and shape in western and northern Indian populations. The researcher also tried to observe and compare the variations of palatal rugae in male and female subjects in each population group.
| Materials and Methods|| |
The materials used were alginate powder from Zelcon, perforated metal maxillary impression trays, mixing bowl, spatula, dental stone, water, black permanent marker, geometric divider, and stainless steel ruler. The subjects for the present study included subjects from western and northern Indian populations who came to the Department of Oral Medicine and Radiology for dental treatment. The criteria for selection are shown in [Table 1].
The study consisted of 100 subjects, 50 each from the two groups of geographically different regions of western and northern India. Each group consisted of 25 males and 25 females who reported to the Department of Oral Medicine and Radiology. The sample size was equally distributed between the genders and the subjects were in the age range of 18-30 years. After obtaining informed consent from the patients, alginate impressions of maxillary arch were made and the study models were poured using dental stone type III for interpretation. The rugae were delineated using a black indelible ink marker pen [Figure 1]. The geometric divider and the stainless steel ruler were used for measuring the length of palatine rugae. The subjects were assigned a unique number and coded serially as they entered the study. The total numbers of rugae were counted on the right and left sides of maxillary cast.
The number, type, and unification pattern were recorded in accordance with the classification of Thomas and Kotze , and the shape was recorded based on Kapali et al.'s classification, , as shown in [Figure 2] and [Table 2].
|Figure 2: Types and unification of palatal rugae patterns: 1) Curve; 2) Wavy; 3) Straight; 4) Circular; 5) Convergent; and 6) Divergent|
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|Table 2: Assesment of palatal rugae pattern according to Thomas and Kotze's and Kapali et al.'s classifications|
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Data obtained were analyzed using statistical software (SPSS version 16.0 software) on a personal computer. The comparisons for the number and type of rugae between the two study groups were done using sample "t0" test. For shape and unification, comparison between groups was done using chi-square test. Sample "t" test was used for comparing the number and type of rugae between genders. Chi-square test was used for comparison of unification and shape.
| Results|| |
Comparisons between the two populations of western and northern India were made according to Thomas and Kotze's classification. The means and standard deviations were recorded for each group and gender. Independent Student "t0" and chi-square tests were used to determine significant differences between the groups and gender. Comparison of the number of rugae between the two populations was done. The P- value was obtained using independent sample "t" test, which was not significant as shown in [Table 3]. The type of rugae was compared between the two study groups by using independent sample "t" test and the P-values for primary, secondary, and fragmentary rugae were found to be statistically non-significant as shown in [Table 4]. The unification patterns between the two study groups were compared by using chi-square test and the P-value was found to be non-significant as shown in [Table 5]. The shape of rugae was compared between the two study groups. On using chi-square test, P-value was found to be highly significant as shown in [Table 6]. Higher proportion of western Indian subjects had straight and wavy shape of rugae, whereas the North Indian population showed wavy and curved rugae.
Comparison between the genders of western and northern Indian subjects was also made according to Thomas and Kotze's classification. The number of rugae was compared between the two genders in each study group. The P-value obtained was highly statistically significant as shown in [Table 7]. The average number of rugae differed significantly between male and female subjects in each study group. Male subjects showed high significance in the number of rugae compared to females in each study group. Type of rugae was compared between the two genders in each study group and the P value obtained showed no statistically significant value as shown in [Table 8]. The unification pattern of rugae was compared between the genders in the western Indian group. A P-value of 0.001 was obtained using chi-square test, which is considered to be highly significant as shown in [Table 9]. The unification pattern of rugae was compared between the genders in the northern Indian group. A P value of 0.011 was obtained using chi-square test, which was considered to be significant. Based on P-value, the unification patterns of rugae differed significantly between the genders of both the groups. The western Indian group showed more significance. On comparing both the populations, more number of rugae was divergent in males whereas females had convergent unification. The shape of rugae was compared between the genders in each study group. The P-value and the degree of freedom were obtained by using chi-square test, which were found to be highly significant as shown in [Table 10]. The shape of rugae differed significantly between male and female subjects in each study group. The western Indian group showed wavy shape predominantly in males; in contrast, majority of the females in this group had straight rugae. Similarly, the northern Indian male participants too had wavy shape; however, females in this group had curved rugae.
|Table 7: Gender wise distribution of the number of rugae in the two Indian populations|
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|Table 8: Gender wise distribution of the type of rugae in the two populations of India|
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|Table 9: Gender wise distribution of the unification of rugae in the two populations of India|
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|Table 10: Gender wise distribution of the shape of rugae in the two population of India|
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| Discussion|| |
Since we entered the new millennium, our society is daily facing multiple challenges in every conceivable area. The most important role of a forensic dentist is the identification of deceased individuals with oro-dental remains in tragedies, disasters, and massacres. Human identification is the mainstay of civilization, whether in living or dead conditions, and the identification of unknown individual has always been of paramount importance to our society. Human identification is based on scientific principles, mainly involving dental records, fingerprints, and DNA typing. Sometimes, it becomes necessary to apply a lesser known and unusual technique like rugoscopy. ,
Palatoscopy or palatal rugoscopy is the name given to the study of palatal rugae patterns. Palatoscopy is of special interest in those cases where other peripheral body parts are grossly destroyed. The uniqueness of palatal rugae led various authors to classify them in the past. The classification which was followed in the present study was given by Thomas and Kotze for number, type, and unification, whereas for shape, Kapali et al.'s classification was used.  The present study was carried out on 100 individuals who were divided into two groups comprising 50 subjects each from North Indian and West Indian population groups. Each group consisted of 25 males and 25 females with equal gender distribution. The results were tabulated and analyzed statistically.
The numbers of rugae on the left and right sides of the cast were compared by Indira et al.,  who carried out a study to observe palatal rugae pattern with respect to gender and found that males had slightly more number of palatal rugae as compared to females. The result of the present study was consistent with that of their study as it revealed that the number of palatal rugae on the left and right sides was slightly more in males as compared to females in both the population groups. This gender-based difference can be used as a major aid in forensic odontology.
In the past, the shape of rugae was compared by Nayak et al.  According to their study, the predominant shape of palatal rugae was wavy and curved shape was more common in both genders. In the present study, on examining the shape of rugae in western Indian population, it was found that straight and wavy shapes were most common. There were significant differences between genders; wavy shape was more common in males and straight shape was more common in female subjects. Although this result is inconsistent with the earlier studies, this parameter can help in gender differentiation of a particular population (western Indian population). On examining the shape of palatal rugae of northern Indian population, wavy and curved shapes were found to be most common. Males showed predominantly high predilection for wavy patterns, whereas female showed predilection toward curved patterns. Even this finding was inconsistent with the result of Nayak et al.,  which however, can help in gender differentiation in a particular population (northern Indian population).
The unification of rugae was compared by Saraf et al.  They found significant differences in unification, as the convergence type was found to be more common in females. In the present study, the unification statistically differed between the genders, but more pronounced difference was found in the western Indian group. Converging type was more commonly seen in females, whereas divergent patterns were more common in the males. This is consistent with the results of Saraf et al.
The incidence of primary, secondary, and fragmentary rugae was studied by Shetty et al.  According to their study, Mysorean males and Tibetan females had more primary rugae than their respective counterparts. In the present study, the incidence of primary, secondary, and fragmentary rugae did not differ significantly between the two genders. This is inconsistent with the results of the study done earlier.
In the present study, we observed that on evaluating the number of rugae, there was a significant difference between male and female subjects which can help in gender identification. Another parameter which showed significant difference was the shape variation between genders in the population under study. When unification was considered in both the groups, the observation showed a clear demarcation in gender related to the patterns of unification. These results can help in ethnic identification and gender differentiation between two geographically different populations. It can be hypothesized that genetics and physiological variations between the populations could have led to these differences.
Literature review shows that the two different populations of the geographical regions of western and northern India which were selected for the present study by the researchers were never studied earlier. The low cost utilization, simplicity, and reliability have added strength to the study. The shortcoming of rugoscopy is that proper identification during postmortem becomes impossible if antemortem data are not available for matching. Another drawback is that intra- and inter-observer errors are likely to occur in cases of complex rugae patterns. This error may be reduced further or completely by development of an intraoral scanning device with appropriate software, which can capture palatal rugae pattern so that the image can be transferred directly to a computer. This would eliminate the manual error as well as the time involved in the process of categorization of rugae pattern. A large amount of data can be stored and quick retrieval of information will be possible which may assist in immediate and effective identification of an individual. It would be beneficial to conduct further studies in large samples and taking more parameters for palatal rugae analysis in all races of the world, so that a national data can be prepared.
| Conclusion|| |
The palatal rugae pattern can act as a fingerprint in identification of a person. The uniqueness of rugae to each individual has already been accepted as a possible aid to personal identification. The analysis of palatal rugae combined with other methods is an important alternative and complementary technique for human identification, which thereby provides a multitude of aid in forensic odontology and significantly contributes in forensic investigations.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8], [Table 9], [Table 10]