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 Table of Contents  
ORIGINAL ARTICLE
Year : 2017  |  Volume : 5  |  Issue : 2  |  Page : 43-47

Comparison of rugae dimensions among dental students from Punjab and Assam: A forensic study


1 Department of Oral Pathology and Microbiology, Surendera Dental College and Research Institute, Sri Ganganagar, Rajasthan, India
2 Department of Conservative Dentistry and Endodontics, Surendera Dental College and Research Institute, Sri Ganganagar, Rajasthan, India
3 Department of Public Health Dentistry, Surendera Dental College and Research Institute, Sri Ganganagar, Rajasthan, India

Date of Web Publication10-Jul-2017

Correspondence Address:
Karthikeyan Ramalingam
Department of Oral Pathology and Microbiology, Surendera Dental College and Research Institute, Sri Ganganagar, Rajasthan
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/dmr.dmr_7_17

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  Abstract 

Background: Identification of an individual is a very important aspect of forensic odontology. Palatal rugae can aid in this identification, as they remain unchanged once formed in embryo. Aim: The aim of the study was to establish the reliability of using the palatal rugae dimensions in identifying the different ethnic groups. Materials and Methods: A total number of sixty participants of two different ethnic groups were taken. The sample size consisted of thirty individuals of Assam and thirty individuals of Punjab between the age range of 17 and 26 years, with 15 males and 15 females in each group. The casts were prepared with alginate impression and digital caliper was used to measure the dimensions of rugae at different points on both right and left sides. Statistical Analysis: Statistical analysis was carried out using SPSS software version 20 with unpaired t-test. Results and Conclusion: The study revealed the statistical significant difference in rugae dimensions of both these ethnic groups.

Keywords: Ethnic groups, forensic odontology, palatal rugae dimensions


How to cite this article:
Tanwar M, Goyal S, Ramalingam K, Kumar Y, Aggarwal K, Aggarwal VP. Comparison of rugae dimensions among dental students from Punjab and Assam: A forensic study. Dent Med Res 2017;5:43-7

How to cite this URL:
Tanwar M, Goyal S, Ramalingam K, Kumar Y, Aggarwal K, Aggarwal VP. Comparison of rugae dimensions among dental students from Punjab and Assam: A forensic study. Dent Med Res [serial online] 2017 [cited 2017 Sep 19];5:43-7. Available from: http://www.dmrjournal.org/text.asp?2017/5/2/43/210121


  Introduction Top


Forensic odontology can be defined as a branch of dentistry which deals with the appropriate handling and examination of dental evidence and with the proper evaluation and presentation of dental findings in the interest of justice.[1] DNA, fingerprint, saliva sample, bite marks, dental records, extracted tooth, and palatal rugae are the most commonly used scientific methods of forensic identification of an individual.[2] Forensic odontology is a very important tool in racial profiling of the human population.[3]

Palatal rugae are also acknowledged as rugae palatine or plica palatine transverse. These are irregular, asymmetrical, anatomical transverse ridges on the anterior portion of the palatal mucosa, located posterior to incisive papilla of the medial palatine raphe, which is just behind the maxillary central incisor teeth.[3] Palatal rugae participate in food breaking, facilitate transport of food from oral cavity, and help in the perception of taste.[1]

Amasaki et al. have reported that the palatal rugae appear in the 3rd month of intrauterine life and occupy most of the palatal shelves during embryonic development. This palatal rugae growth is controlled by epithelial-mesenchymal interaction, where specific extracellular matrix molecules are spatiotemporally expressed during development.[4]

The study of palatal rugae or rugae palatine is acknowledged as palatal rugoscopy or palatoscopy.[5] Peavey and Kendrick in their study identified that palatal rugae do not alter as a result of growth but remain stable in their number and shape throughout life.[6] They remain sheltered from trauma and injury and high temperature because of their position in the oral cavity, protected by cheeks, tongue, lips, teeth, and arches.[3]

Forensic analysis can be done by assessment of palatal rugae.[3] Various studies have been proposed that these palatal rugae are unique and distinct to an individual and thus rugae could be equated to bite marks and fingerprints for personal identification. The study shows that even in identical twins, palatal rugae are not identical.[7]

A PubMed search was performed for “rugae dimensions of palate” and only seven articles are published till date with only two studies from Indian perspective.[8],[9] Hence, this present study was done to establish the reliability of using the palatal rugae dimensions in identification of the different ethnic groups.


  Materials and Methods Top


The study was conducted at the Department of Oral Pathology, Surendera Dental College and Research Institute, Sri Ganganagar, Rajasthan, India. The samples were obtained from the dental students of two different ethnic groups belonging to different geographic areas. The participants with a complete set of dentition and fully erupted teeth were only considered in the study. The participants with systemic illness, orthodontic therapy, palatal prosthesis, cleft lip, or cleft palate were excluded from the study.

A total number of sixty participants (n = 60), thirty males and thirty females were selected from among the students of the college based on their place of birth. The individuals selected were aged between 17 and 26 years comprising thirty Punjab students and thirty Assam students. The selection comprised 15 males and 15 females. The study sample was divided into the following four groups, namely, the boys from Punjab, the boys from Assam, the girls from Punjab, and girls from Assam.

The procedure was in accordance with the Institutional Ethical Committee on human experimentation and with Helsinki Declaration of 1975 as revised in 2000.[9] The participants were briefly explained about the study and were asked to rinse the oral cavity with water. Impression was made using alginate impression compound. Alginate impression of the maxillary arch was taken with sterilized perforated tray. These impressions obtained were poured with type III dental stone following manufacturer's instructions [Figure 1]. The cast thus obtained was used for analysis.
Figure 1: Armamentarium used for preparation of the casts

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A digital caliper was used to measure rugae patterns on the dental cast, and the dimension was recorded for the analytical purpose [Figure 2].
Figure 2: Digital vernier caliper

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The following dimensions were noted following the method given by Patil et al.[9] The measurements from each cast were as follows: AB distance was the distance between the most anterior point on the incisive papilla and the most medial point of the first primary rugae. AC distance was the distance between the most anterior point on the incisive papilla and the most medial point of the last primary rugae. BC distance was the distance between the medial points of the first and the last primary rugae. This distance is calculated by subtracting the AB distance from the AC distance [Figure 3], [Figure 4], [Figure 5], [Figure 6].
Figure 3: Maxillary cast showing the rugae pattern of an Assamese boy

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Figure 4: Maxillary cast showing the rugae pattern of an Assamese girl

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Figure 5: Maxillary cast showing the rugae pattern of a Punjabi boy

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Figure 6: Maxillary cast showing the rugae pattern of a Punjabi girl

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All the dimensions were measured by two investigators with calibration at two different time intervals for reliability and reproducibility. The proportions for the right and the left sides of each cast were noted. The mean value of both measurements was calculated and tabulated [Graph 1].



Statistical analysis was carried out using the unpaired t-test. The Statistical Package for the Social Sciences software version 20 (SPSS Inc. Chicago, IL, USA) was used for the statistical analysis and P < 0.05 was considered statistically significant.


  Results Top


  • The mean A–B dimensions showed significant statistical difference among the Punjab boys and Assam boys [Table 1] and among Punjab boys and Punjab girls [Table 2]. However, their mean dimensions were statistically not significant among the Punjab girls and Assam girls [Table 3] and among Assam boys and Assam girls [Table 4]
  • The mean B-C dimensions showed significant statistical difference among the Punjab girls and Assam girls [Table 5]. However, their mean dimensions were statistically not significant among the Punjab boys and Assam boys [Table 6], among the Punjab boys and Punjab girls [Table 7], and among the Assam boys and Assam girls [Table 8]
  • The mean A–C dimensions showed nonsignificant statistical difference among the Punjab boys and Assam boys [Table 9], among the Punjab girls and Assam girls [Table 10], among the Punjab boys and Punjab girls [Table 11], and among the Assam boys and Assam girls [Table 12].
Table 1: Mean palatal rugae dimensions among Punjab boys and Assam boys at A–B distance

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Table 2: Mean palatal rugae dimensions among Punjab boys and Punjab girls at A–B distance

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Table 3: Mean palatal rugae dimensions among Punjab girls and Assam girls at A–B distance

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Table 4: Mean palatal rugae dimensions among Assam boys and Assam girls at A–B distance

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Table 5: Mean palatal rugae dimensions among Punjab girls and Assam girls at B-C distance

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Table 6: Mean palatal rugae dimensions among Punjab boys and Assam boys at B-C distance

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Table 7: Mean palatal rugae dimensions among Punjab boys and Punjab girls at B-C distance

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Table 8: Mean palatal rugae dimensions among Assam boys and Assam girls at B-C distance

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Table 9: Mean palatal rugae dimensions among Punjab boys and Assam boys at A–C distance

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Table 10: Mean palatal rugae dimensions among Punjab girls and Assam girls at A–C distance

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Table 11: Mean palatal rugae dimensions among Punjab boys and Punjab girls at A–C distance

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Table 12: Mean palatal rugae dimensions among Assam boys and Assam girls at A–C distance

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  Discussion Top


Forensic odontology is the application of dental science to legal investigations, primarily involving the identification of the offender by comparing dental records to a bite mark left on the victim or at the scene, or identification of human remains based on dental records and deals with appropriate handling and examination of dental evidence.[4]

Palatal rugae are the anatomical irregular folds present bilaterally on the midpalatal raphe.[5] The palatal rugae study is known as palatal rugoscopy or palatoscopy. These rugae remain steady in their number and shape throughout life and do not undergo any change due to growth.[6]

Different oral methods of human identification in forensic dentistry includes dental arch examination, palatal rugae, finger prints, tooth extractions for the posterior examination of the DNA of the dental pulp, and saliva assessment, but the most common method for identification is visual methods and is more reliable and trustworthy. Since palatal rugae resist changes throughout life, this makes them stable for the use in identification of an individual.

Various classifications have been proposed for the rugae patterns. Thomas and Kotze proposed the reference points to calculate the rugae pattern dimensions.[10] In the present study, Lysell classification [11] of rugae was followed, those rugae which had a length of more than 5 mm referred to as primary rugae and rugae which had length between 3 and 5 mm referred to as secondary rugae were recorded, whereas the fragmentary rugae with length 2 mm or less were excluded for the study.

Many studies have been completed to associate the rugae pattern.[12],[13],[14],[15],[16],[17],[18],[19],[20],[21],[22],[23] Shetty et al. compared palatal rugae pattern in Kodava and Malayalam speaking population of South India on thirty participants and concluded that the differences in rugae shape between the two populations (wavy and unification patterns) may be attributed to genetic factors, and recent shared ancestry has probably rendered their differences to moderate levels.[12] Kotrashetti et al. determined palatal rugae patterns among two ethnic populations of India on 100 participants by logistic regression analysis, and they concluded significant difference recorded among straight, wavy, circular, and divergent pattern between two populations. This study demonstrated moderate accuracy of palatal rugae pattern in identification.[13] Kallianpur et al. performed anthropometric analysis of facial height, arch length, and palatal rugae in the Indian and Nepalese population, on sixty Indians and sixty Nepalese and they concluded that Arch length and palatal rugae characteristically vary between the two different ethnic groups.[14]

Ahmed et al. did morphological study of palatal rugae in a Sudanese population on 100 participants and concluded the palatal rugae are not recommended for assigning sex effectively among Sudanese Arabs unless only it is the only means available.[15] Adisa et al. studied palatal rugae as a tool for human identification on fifty Nigerian participant and concluded Rugoscopy is a useful technique for human identification due to the unique rugae pattern in every individual. However, without the aid of ancillary aids, visual inspection alone can be challenging.[16]

A PubMed search was done which showed that total 16 studies had been done on palatal rugae pattern, whereas only 7 studies had been done on palatal rugae dimension, of which only one is performed on Indian population. Chatterjee and Khanna studied dimensional analysis of various rugae patterns in North Indian population subset on 100 participants and concluded that a significant change in the anteroposterior medial rugae dimensions was seen in adolescent age groups alongside no variation in palate depth.[8] Patil et al. studied rugae dimensions and their significance in forensic dentistry, on thirty Kannada speaking and thirty Malayalam speaking participants and they concluded significant difference in the palatal rugae dimensions among the Karnataka and Kerala individuals.[9]

Hence, in the present study, palatal rugae dimension was taken into consideration to evaluate the importance of palatal rugae dimension in forensic odontology.

In the present study, the palatal rugae dimensions were calculated by measuring A–B, B–C, and A–C dimensions. The study showed that Assam boys had statistically significant greater A–B dimensions as compared with Punjab boys. The Punjab girls had statistically significant greater A–B dimensions as compared with Punjab boys. The Assam girls also had statistically significant greater B-C dimensions as compared with Punjab girls.

Palatal rugae possess features of identification because of its uniqueness, resistance to trauma and injury, and its stability; therefore, they could be used in forensic odontology.


  Conclusion Top


The present study showed that Assam girls had greater palatal rugae dimensions as compared to Punjab girls and Assam boys. The Assam boys had greater palatal rugae dimension as compared to Punjab boys.

We need a larger sample size of the representative population to confirm our findings. Since only a few studies have been conducted on this topic, further research could ascertain the consistency of using the palatal rugae dimensions in recognition of different racial groups. Finally, we suggest the usage of palatal rugae dimension as an unswerving tool in forensic identification.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
  References Top

1.
Saraf A, Bedia S, Indurkar A, Degwekar S, Bhowate R. Rugae patterns as an adjunct to sex differentiation in forensic identification. J Forensic Odontostomatol 2011;29:14-9.  Back to cited text no. 1
    
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Chatterjee S, Khanna M. Dimensional analysis of various rugae patterns in North Indian population subset. J Forensic Dent Sci 2011;3:86-8.  Back to cited text no. 8
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Lysell L. Plicae palatinae transversae and papilla incisiva in man; a morphologic and genetic study. Acta Odontol Scand 1955;13 Suppl 18:5-137.  Back to cited text no. 11
    
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Shetty DK, Machale PS, Savant SC, Taqi SA. Comparison of palatal rugae patterns in Kodava and Malayalee populations of South India. J Forensic Dent Sci 2013;5:85-9.  Back to cited text no. 12
[PUBMED]  [Full text]  
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Kotrashetti VS, Hollikatti K, Mallapur MD, Hallikeremath SR, Kale AD. Determination of palatal rugae patterns among two ethnic populations of India by logistic regression analysis. J Forensic Leg Med 2011;18:360-5.  Back to cited text no. 13
    
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Kallianpur S, Desai A, Kasetty S, Sudheendra U, Joshi P. An anthropometric analysis of facial height, arch length, and palatal rugae in the Indian and Nepalese population. J Forensic Dent Sci 2011;3:33-7.  Back to cited text no. 14
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Patil MS, Patil SB, Acharya AB. Palatine rugae and their significance in clinical dentistry: A review of the literature. J Am Dent Assoc 2008;139:1471-8.  Back to cited text no. 20
    
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    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8], [Table 9], [Table 10], [Table 11], [Table 12]



 

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