Forensic dentistry is the dental speciality that relates & applies dental knowledge to legal problems. Rugae pattern is as unique to a human as one’s fingerprints & retains its shape throughout life. The anatomical position of the rugae inside the mouth keeps them well-protected from trauma & high temperature. Hence they serve as an effective landmark for forensic identification.
To find the difference in pattern of rugae between normal healthy individuals and those with periodontitis and correlation in male and female individuals.
The present study included maxillary casts of attending patients who were divided into 2 groups: (1)75 normal patients and (2)75 patients having periodontitis. Palatal rugae pattern were then evaluated for the number and shape.
The number of rugae was more in normal healthy individuals as compared to those with periodontitis. Circular pattern and wavy pattern was more prevalent in healthy individuals and periodontitis patients respectively. Males had more number of rugae and straight pattern was greater as compared to females who showed predominant wavy pattern.
Rugae pattern is a reliable reference landmark during forensic identification. Although we have found differences in pattern of rugae in normal healthy individuals and those with periodontitis, further studies are required to be carried out with a greater sample size to achieve significant results.
Keywords: Forensic, Rugae, Periodontitis
The identification of human remains is important due to both legal and humanitarian reasons. It is based on the scientific matching of information on missing persons with unidentified human remains. Dental, fingerprints and DNA comparisons are the most common techniques used for secure identification. However, since they cannot always be used, sometimes it is necessary to apply different and less known techniques.
Forensic dentistry (odontology) is the dental speciality that relates & applies dental knowledge to legal problems. Proper forensic identification is also necessary to claim certification of death.
Visual identification is the most common method applied in forensic sciences. However, in certain incidences where hard tissues of the oral cavity are lost due to any reasons such as trauma, visual means of identification is significant in non-mutilated palatal tissues. Thus, in forensic dentistry, the unique characteristic pattern of palatal rugae can be used as an identification tool [1]. The anatomical position of the rugae inside the mouth-surrounded by cheeks, lips, tongue, buccal pad of fat, teeth & bone—keeps them well-protected from trauma & high temperatures.
Thus, they can be used reliably as a reference landmark during forensic identification. Palatal rugae in mammals are transversely running crests, which are exclusively formed by the mucosa of the hard palate except where an ossified base can be distinguished. According to the Glossary of Prosthodontic Terms-8, rugae are anatomical folds or wrinkles; the irregular fibrous connective tissue located on the anterior third of the palate. They are also called “plica palatinae” or “rugae palatine”. It is assumed that the rugae facilitate food transport through the oral cavity, prevent loss of food from the mouth and participate in food crushing. Because of the presence of tactile and gustatory receptors, rugae contribute to perception of taste, mechanical food qualities and tongue position [2]. Palatal rugae are formed in the third month in utero from the hard connective tissue covering bone. The pattern orientation is formed by about 12th to 14th week of prenatal life.
Histologically, the rugae are stratified squamous mainly parakeratinized epithelium on a connective tissue base, similar to the adjacent tissue of the palate. Thomas [3] reported differences in the rugae cores taken from human embryos of over 20 weeks. He found the reticulin fiber content to be very delicate and the fibroblasts to be different in amount and size from that in adjacent palatal tissue. Many researchers have studied the morphology of palatal rugae and the racial differences, but very few have studied the individuality of palatal rugae.
Due to their internal position in head they are well protected by trauma. Palatoscopy or palatal rugoscopy is the name given to the study of palatal rugae in order to establish a person's identity [4]. The application of palatal rugae patterns for personal identification was first suggested by Allen [5] in 1889.Palatal rugoscopy was first proposed in 1932, by a Spanish investigator named Trobo Hermosa [6]. In 1937, Carrea [7] conducted a detailed study and established a method to classify palatal rugae. In 1983, Brinon [7] following the studies of Carrea, divided palatal rugae into two groups (fundamental and specific) in a similar way to that done with fingerprints [6, 7].
These type of rugae
These type have a
Slight bend at the termination or origin of rugae
The shape is like
There is slight curve at the origin or termination
The rugae have a definite
Objective of this study was to find the difference in pattern of rugae between Normal Healthy Individuals and those with Periodontitis and correlation in Male and Female individuals
The study consisted of 2 groups of attending patients to the Department of Periodontics, Pandit Deendayal Upadhyay Dental College, Solapur, India
Normal patients
Patients having Periodontitis
The study consisted of 75 patients with normal healthy gingiva and 75 patients with Periodontitis. Informed consent was obtained from all patients according to the Helsinki Declaration of 1975 as reviewed in 2000.The study design was approved by the Ethics Committee. Patients with trauma, congenital abnormalities of palate, those undergone surgery were excluded from the study.
Alginate impression of the maxillary arch was made in stock trays. The study casts were prepared in dental plaster for interpretation. The rugae appeared as prominent ridges were delineated using a sharp graphite pencil & recorded according to the Modified Lysell Classification (1955). The recordings were made by a single examiner. Origin is that point of rugae nearest to the midline and termination is the point where the rugae end from the origin. The data collected were subjected to statistical analysis.
Fig. 1, 2, 3 Casts showing tracing of Rugae Pattern according to Modified Lysell Classification
In this study, the number of rugae and their pattern was studied in 150 Plaster models.
|
|
|
|
|
|
|
|
|
|
|
|
|
|||||||
| Curved | Normal | 1.4800 | .92063 | .42667 | .13548 | .71785 | 2.896 |
|
| Periodontitis | 1.0533 | .88369 | ||||||
| Wavy | Normal | 1.1333 | .97722 | -.42667 | -.77571 | -.07763 | -2.416 |
|
| Periodontitis | 1.5600 | 1.17680 | ||||||
| Straight | Normal | 1.1733 | 1.03157 | .18667 | -.12689 | .50022 | 1.176 | .241 |
| Periodontitis | .9867 | .90782 | ||||||
| Circular | Normal | 1.8667 | 1.05694 | .70667 | .39648 | 1.01686 | 4.502 |
|
| Periodontitis | 1.1600 | .85487 | ||||||
In Table 1 number of curved rugae was seen to be more in Normal patients than Periodontitis patients. The P value was found to be 0.004 which was statistically significant. Wavy pattern was more prevalent in Periodontitis patients than Normal patients, which was statistically significant (P = 0.017).Straight pattern was seen more in Normal patients than in Periodontitis but this difference was not statistically significant. Circular pattern was seen to be statistically more significant in Normal than Periodontitis patients (P= 0.000).
Thus, it was evaluated that circular pattern was more prevalent in Normal Patients whereas wavy pattern was more prevalent in Periodontitis patients. In Tables 2,3,4,5 Distribution of subjects according to curved, wavy, straight, circular rugae pattern in normal group has been evaluated.
|
|
|
|
| .00 | 8 | 10.7 |
| 1.00 | 35 | 46.7 |
| 2.00 | 22 | 29.3 |
| 3.00 | 8 | 10.7 |
| 4.00 | 2 | 2.7 |
|
|
|
|
| .00 | 20 | 26.7 |
| 1.00 | 33 | 44.0 |
| 2.00 | 17 | 22.7 |
| 3.00 | 2 | 2.7 |
| 4.00 | 3 | 4.0 |
|
|
|
|
| .00 | 19 | 25.3 |
| 1.00 | 36 | 48.0 |
| 2.00 | 11 | 14.7 |
| 3.00 | 6 | 8.0 |
| 4.00 | 3 | 4.0 |
|
|
|
|
| .00 | 3 | 4.0 |
| 1.00 | 30 | 40.0 |
| 2.00 | 24 | 32.0 |
| 3.00 | 10 | 13.3 |
| 4.00 | 8 | 10.7 |
In Tables 6,7,8,9 Distribution of subjects according to curved, wavy, straight, circular rugae pattern in periodontitis group has been evaluated.
|
|
|
|
| .00 | 19 | 25.3 |
| 1.00 | 39 | 52.0 |
| 2.00 | 13 | 17.3 |
| 3.00 | 2 | 2.7 |
| 4.00 | 2 | 2.7 |
|
|
|
|
| .00 | 11 | 14.7 |
| 1.00 | 33 | 44.0 |
| 2.00 | 16 | 21.3 |
| 3.00 | 10 | 13.3 |
| 4.00 | 3 | 4.0 |
| 5.00 | 2 | 2.7 |
|
|
|
|
| .00 | 24 | 32.0 |
| 1.00 | 34 | 45.3 |
| 2.00 | 12 | 16.0 |
| 3.00 | 4 | 5.3 |
| 4.00 | 1 | 1.3 |
|
|
|
|
| .00 | 15 | 20.0 |
| 1.00 | 39 | 52.0 |
| 2.00 | 16 | 21.3 |
| 3.00 | 4 | 5.3 |
| 4.00 | 1 | 1.3 |
In Table 10 ; the number of rugae was found to be more in Normal patients than those seen in Periodontitis patients and this difference was statistically significant with p = 0.007. In the Normal group, the number of rugae was 424 and it was 357 in the Periodontitis group with a mean difference of 0.22333.
|
|
|
|
|
|
|
|
|
|
|
|
||||||
| Normal | 1.4133 | 1.03573 | .22333 | .06126 | .38541 | 2.706 |
|
| Periodontitis | 1.1900 | .98512 | |||||
This is in contradiction to studies which prove that rugae pattern Do not change throughout life. Variations do occur in the pattern and number of rugae due to disease processes. Differences in rugae were also observed as sex varied. When compared to males and females, the number of rugae was found to be more in males than females. It was 432 in males and 349 in females. Males had predominant straight pattern whereas Females had predominant wavy pattern.
There exist certain limitations for identification by fingerprints, DNA , dental records in some situations. In such cases, rugae have been widely used in population identification. Application of palatal rugae patterns for personal identification was suggested by Allen in 1889. The term "Palatal rugoscopy" was first proposed by the Spanish investigator Trobo Hermosa [6].
There are several ways to analyze palatal rugae like calgurroscopy, stereoscopy, oral photography. In this study, the method of intraoral inspection was chosen as it is the easiest and cheapest method among the rest. There are different classification systems to analyze rugae as well. But the classification system based on shape was selected as it is easy to record and does not need complex instrumentation. Rugae shape proves to be more accurate than rugae length. Hence this classification system better suited.
In this study, both shape and number analysis was done. The size and shape of rugae pattern was compared in males and females as well as in normal patients as compared to those having periodontitis. There are numerous studies for analysis of rugae in normal population and also for gender identification [9, 10, 11, 12]. Arora et al. who compared two different populations and found that there were significant differences seen between rugae pattern of two different populations. But this study compares the rugae pattern in normal patients to those in chronic periodontitis. Jindal et.al compared the rugae pattern in patients having gingivitis, chronic periodontitis and aggressive periodontitis [13]. They used the Trobo classification for study of palatal rugae.
Kapali et al
However, there are some contradictory studies as well. According to English's studies [17], palatal rugae patterns are sufficiently characteristic to discriminate between individuals. It was stated that rugae pattern was absolutely unique to an individual and could be used for identification [18].
But our study showed differences in rugae pattern when patients with gingivitis and periodontitis were compared. As these were inflammatory conditions they could damage the pattern of rugae in individuals and make identification difficult. There were differences found in the rugae pattern in males and females as well. As the sample size considered was small, further studies with large sample size are required.
In our study,the number of rugae was found to be more in Normal Healthy individualsas compared to those having Periodontitis.
Circular pattern was more prevalent in healthy individuals and wavy pattern was prevalent in patients with Periodontitis.
Males showed more number of rugaethan females.
Males had predominant straight pattern whereas Females had predominant wavy pattern.
These findings were within the limited sample size. So further studies are warranted.
English WR, Robison SF, Summitt JB, et al
Buchtova M, Tichy F, Putnova I, et al The development of palatal rugae in the European pinevole, Microtus subterraneus(Arvicolidae, Rodentia).
Thomas CJ. The prenatal developmental microscopic anatomy of palatal rugae.
Ines Morais Caldas, Establishing identity using cheiloscopy and palatoscopy.
Allen H. The palatal rugae in man.
Pueyo VM, Garrido BR, Sanchez JA. Odontologialegal. Forense, Masson, Barcelona: 1994, 277-92.
CamposML,Rugoscopia palatine.Available from:http://www.periciasforenses.com.br
Kapali S, Townsend G, Richards L, Parish T, Palatal rugae patterns in Australian Aborigines and Caucasians.
Limsom KS, Thomas CJ, Kotze TJ. Computerized recording of the palatal rugae pattern and evaluation of its application in forensic identification.
Saraf A, Bedia S, Indurkar A, et al Rugae patterns as an adjunct to sex differentiation in forensic identification.
Fahmi FM, Al‑Shamrani SM, Talic YF. Rugae pattern in a Saudi population sample of males and females.
English WR, Robinson SF, Summitt JB, et al. Individuality of human palatal rugae.
Jindal V, Mahajan A, Mahajan N, et al. Rugae pattern determination in periodontitis patients: A descriptive study.
Peavy DC Jr., Kendrick GS. The effects of tooth movement on the palatine rugae.
Dohke M and Osatio S. Morphological study of the palatal rugae in Japanese 1. Bilateral differences in the regressive evaluation of the palatal rugae.
Fahmi MF et al. Rugae pattern in a Saudi population sample of males and females.
El-Fotoh MM, El-Sharkawy GZH. A study of palatal rugae pattern (rugoscopy) in an Egyptian population.
Lysell L. Plicae palatinae transversae and papilla incisive in man: A morphologic and genetic study.