|Year : 2014 | Volume
| Issue : 4 | Page : 405-409
Prevalence of different palatal rugae patterns in a sample Lucknow population
Mohammed Asdullah, Srinivas Kandakurti, Arti S Sachdev, Vasu S Saxena, Ratnakar Pamula, Jyoti Gupta
Department of Oral Medicine and Radiology, Career Postgraduate Institute of Dental Sciences and Hospital, Lucknow, Uttar Pradesh, India
|Date of Submission||12-Sep-2014|
|Date of Acceptance||07-Apr-2015|
|Date of Web Publication||22-Apr-2015|
Department of Oral Medicine and Radiology, Career Post Graduate Institute of Dental Sciences and Hospital, Gailla, Lucknow, Uttar Pradesh
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Introduction: Palatoscopy is the study of palatal rugae pattern and it can be used to establish the identity of a person. The rugae are unique internal structures protected by the lips, buccal pad of fat and teeth that resist decomposition, thus serving an important role in forensic identification. The appearance of palatal rugae is constant, as they do not demonstrate changes after the completion of growth of the individual, thus increasing its utility as a personal identification tool. Aims and Objectives: To study the prevalence of different palatal rugae patterns in a sample of Lucknow, India population. Materials and Methods: The study comprised 100 healthy (50 males and 50 females) subjects of age between 18 and 40 years, who were randomly selected. In this study we used the classification of rugae patterns suggested by Kapali et al. (straight, curved, wavy andcircular), and Thomas and Kotze (unification and nonspecific). Results: The mean rugae number in females was slightly more than males. The most prevalent forms in both genders were curved type followed by wavy, straight and diverging types. Straight and curved forms were significantly more in numbers in females than males. Conclusion: This is a preliminary study on a localized Indian population. Scope still exists for further studies to determine gender as well as personal identification. We believe that rugae can be used as a reliable guide in forensic identification.
Keywords: Forensics, palatoscopy, rugae pattern
|How to cite this article:|
Asdullah M, Kandakurti S, Sachdev AS, Saxena VS, Pamula R, Gupta J. Prevalence of different palatal rugae patterns in a sample Lucknow population. J Indian Acad Oral Med Radiol 2014;26:405-9
|How to cite this URL:|
Asdullah M, Kandakurti S, Sachdev AS, Saxena VS, Pamula R, Gupta J. Prevalence of different palatal rugae patterns in a sample Lucknow population. J Indian Acad Oral Med Radiol [serial online] 2014 [cited 2019 Sep 17];26:405-9. Available from: http://www.jiaomr.in/text.asp?2014/26/4/405/155687
| Introduction|| |
Palatal rugae (PR) or transverse palatine folds are irregular and asymmetrical ridges of the mucosa located in the anterior third of the palate behind the incisive papillae originating from the lateral membrane of the incisive papilla and arranged transversely on either side of the median palatine raphe [Figure 1]. Palatoscopy has gained importance in the recent past. ,,, Postmortem identification using teeth can be used for individuals who possess teeth, but in certain situation where the teeth are lost or a person is edentulous, the identification becomes difficult. In such cases palatal rugae can be used as an alternative adjunct in forensic identification.  The rugae are unique internal structures, protected by the lips, buccal pad of fat and teeth that resist decomposition. They can resist decomposition changes for up to 7 days after death. , The palatal rugae pattern remains stable throughout an entire person's life following the completion of growth.  Additionally, it has been reported that they retain their stability even during orthodontic treatment and extraction of teeth thus serving an important role in forensic identification.  The palatal rugae pattern are highly individualistic, uniquely structured and specie specific.  In this study we used the classification of rugae patterns suggested by Kapali et al.  (straight, curved, wavy and circular) and Thomas and Kotze  (unification and nonspecific).
| Aims and Objectives|| |
The aim of the study was to analyse the prevalence of different palatal rugae patterns in a sample of Lucknow, India population. The classification of rugae patterns suggested by Kapali et al.  (straight, curved, wavy and circular) and Thomas and Kotze  (unification and nonspecific) was used to identify different types of rugae in this study.
| Materials and Methods|| |
This study was conducted in the Department of Oral Medicine and Radiology, Career Post Graduate Institute of Dental Sciences and Hospital, Lucknow. A total of 100 subjects, 50 males and 50 females, in the age group of 18-40 years were chosen randomly and included in the present study. The study was conducted after obtaining institutional ethical committee clearance and informed written consent from the subjects.
Subjects without braces, removable partial dentures and fixed partial dentures were included.
Subjects with abnormalities of palate and lips like cleft palate and cleft lip.
Alginate powder, perforated metal maxillary impression tray, mixing bowl, spatula, dental stone and water for mixing.
Maxillary impressions of the subject were made using alginate in a perforated impression tray. The impression was washed in running tap water and the cast was obtained using high strength dental stone. All palatal rugae on the cast were delineated using a sharp tip HB pencil under adequate light irrespective of their length. The rugae pattern was recorded according to Kapali et al. classification (1997) as straight, curved, wavy and circular, and according to Thomas and Kotze classification (1983) as unification/branching and nonspecific [Figure 2]a and b. Unification was further classified as diverging or converging, depending on the type of origin.
|Figure 2: Different types of palatal rugae delineated in maxillary cast- (a) showing circular (C), wavy (W) and straight (S) types, and (b) showing nonspecifi c (NS), curved (CU), straight (S), unifi cation (U) and wavy (W) types|
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The rugae were classified based on the following features:
- Straight (S): They were classified as straight if the rugae were straight from their origin to termination
- Curved (CU): They were classified as curved if the rugae were crescent shaped and curved gently
- Wavy (W): They were classified as wavy if a curved rugae bore an additional slight curve at the origin or termination
- Circular (C): They were classified as circular if the rugae formed a definite continuous ring
- Unification (U): They were classified as unified if two rugae joined at their origin or termination. These were further classified as diverging or converging, depending on the type of origin:
- Diverging- If two rugae had the same origin from the midline which immediately branched
- Converging- If two rugae had different origins from the midline which joined on their lateral portions
- Nonspecific (NS): They were classified as nonspecific if they did not fall in any of the five types mentioned above.
The observations were repeated after 1 week to rule out intraobserver variability.
| Results|| |
The prevalence of different types of rugae in males and females is described in [Table 1]. The mean rugae number in females was slightly more than males [Graph 1 [Additional file 1] ] and [Table 2]. The most prevalent forms in both genders were curved type followed by wavy, straight and diverging types [Graph 2 [Additional file 2] ] and [Graph 3 [Additional file 3] ], [Table 1] and [Table 3]. Converging and nonspecific types were also recorded. Straight and curved forms were significantly more in numbers in females than males [Table 1].
|Table 3: Descriptive statistics of different types of rugae (n = 884) in 100 individuals (males and females)|
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A total of 884 palatal rugae were observed in the 100 subjects, almost equally divided on the left and right side of the medial palatal raphe. Average number of rugae found in each individual was 8.84 of which 4-5 rugae were on each side of the palate. In the 50 females, a total number of 452 rugae were identified with a mean value 9.04 ± 30.53 (mean ± SD), while in the 50 males a total number of 432 rugae were observed with a mean value 8.64 ± 28.25 (mean ± SD). Statistically, no significant difference (P = 0.94) was observed in the number of rugae in males and females [Table 2]. Also no significant differences were found in the left and right side of palate.
Out of the 884 rugae found in 100 individuals, 284 (32.12%) were of the curved type, which were maximum in number followed by the wave type found in 257 (28.73%) rugae, straight type found in 212 (23.98%) rugae, diverging type found in 45 (5.09%) rugae, nonspecific type found in 44 (4.97%) rugae, and the converging type were found in 35 (3.95%) rugae. Circular type were also observed, but were negligible in number (12 in number, 1.35%). In males as well as females the mean proportion of the curved type was observed to be maximum (mean value in males being 2.72%, while in females 2.96%), followed by the wave type (mean value in males being 2.60% and in females 2.54%), straight type (mean value in males being 2.04%, while in females 2.46%), diverging type (mean value in males being 0.42%, while in females 0.46%), nonspecific type (mean value in males being 0.46%, while in females 0.42%) and converging type (mean value in males being 0.36%, while in females 0.34%). The circular type (mean value in males being 0.14%, while in females 0.10%) was found negligibly [Table 3].
| Discussion|| |
There is epithelial proliferation and thickening in localized regions from which the palatal rugae actually develop. Beneath this thickened epithelium, within the connective tissue, fibroblasts and collagen fibers accumulate. The orientation of the rugae is determined by these fibers running antero-posteriorly within the core and in concentric curves across the base of each rugae.  Its design and structure remain unchanged throughout life and can be used effectively in forensic sciences for person identification.
The most common methods of identification are visual, fingerprint and dental characteristics. Visual method is the best method to identify a person but in case of mass disasters it becomes difficult. Fingerprints have long been the standard identification process but ante-mortem records of fingerprints are often unavailable especially in cases involving fire, decomposition or massive trauma. Similarly, identification using dental characteristics may also pose problems in certain situations, like missing teeth in case of a disaster, making it difficult to identify a person. An ideal post mortem identifier is one that is present in all victims and is resistant to change.  Identification based on palatal rugae can be used in dental and forensic practice as they remain stable over a person's life. In addition, they show a significant association between their shape and ethnicity.
In our study, a total of 884 palatal rugae were observed in 100 subjects. In 50 males, a total numbers of 432 rugae were identified with a mean value of 8.64. While in 50 females, a total of 452 rugae were observed with a mean value of 9.04. Statistically, no significant differences were observed in the number of rugae between males and females (P = 0.94). This finding was consistent with the finding of Kapali et al. (1997).  However, Kamala et al. in 2011,  found more total number of rugae in males than females. This discrepancy may be related to the difference in total number of subjects who participated in the study.
In the present study, the curved-shape rugae were found to be maximum in numbers followed by wavy, straight, diverging, nonspecific, converging and circular types. Similar results were declared by Kapali et al. (1997),  Kamala et al.(2011),  and Mahabalesh et al. (2011).  They concluded that the most common shapes of palatal rugae were curved, wavy and straight forms, whereas converging and circular were least in numbers. In the present study, curved, straight and circular-shaped rugae were slightly less in number in male patients as compared to female patients. However, this was not significant statistically [Table 3]. This finding was consistent with the finding of Kapali et al. (1997)  and Kamala et al. (2011),  but differed from the finding of Fahmi et al. (2001).  The limitation of our study is the small sample size. Hence, more number of Indian populations should be studied to determine the accuracy of palatal rugae in identification.
| Conclusion|| |
Palatoscopy is a technique that can be of great interest in human identification. It is unique to an individual and can be used successfully in identification. This is a preliminary study on a localized Indian population. Scope still exists for further studies to determine gender as well as personal identification.
| Acknowledgment|| |
The authors acknowledge the help rendered by Dr. Payal Tripathi, Dr. K. Aravinda, Dr. Satish Kumar and Dr. Monu Yadav, in the conduction of this study.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3]