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 Table of Contents  
ORIGINAL ARTICLE
Year : 2017  |  Volume : 6  |  Issue : 9  |  Page : 21-25

Mandible in personifying the identity of individuals in mass disasters: An original study with forensic interest


1 Department of Oral Medicine and Radiology, Saraswati-Dhanwantari Dental College and Hospital and Post-Graduate Research Institute, Parbhani, Maharashtra, India
2 Department of Orthodontics and Dento-facial Orthopedics, VSPM Dental College and Hospital and Post-Graduate Research Institute, Nagpur, Maharashtra, India
3 Department of Oral and Maxillo-facial Pathology, Saraswati-Dhanwantari Dental College and Hospital and Post-Graduate Research Institute, Parbhani, Maharashtra, India
4 Department of Biostatistics, Georgia State University, Atlanta, Georgia, United States
5 Department of Oral Medicine and Radiology, Sibar Institute of Dental Sciences, Guntur, Andhra Pradesh, India

Date of Web Publication2-Aug-2017

Correspondence Address:
Abhishek Singh Nayyar
44, Behind Singla Nursing Home, New Friends' Colony, Model Town, Panipat - 132 103, Haryana
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/nnjcr.nnjcr_23_16

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  Abstract 


Context: Disaster is an unforeseen and sudden event that causes great destruction, damage, and human suffering. The World Disaster Report published in 2012 showed that the total number of people affected by disasters had significantly increased in the last few decades. This signifies the role of forensic anthropologists in personifying the identity of individuals during mass disasters. The age and sex of an individual can be determined by means of skeletal indicators when soft tissues are not available for analysis. Pelvis is the best skeletal indicator for sex determination. Next to pelvis, skull and head of femur are the next most important skeletal indicators. Furthermore, when the entire skull is not available for analysis, mandible plays a vital role as it is one of the strongest bones in the skull showing dimorphism. Various studies conducted in the past have proven the accuracy of panoramic radiographs in providing anatomical measurements helpful in the identification of individuals. The present study was conducted using digital orthopantomographs (OPGs) for the same. Aim: This study aims to measure and compare various measurements of the ramus in mandible on digital OPGs and to assess the usefulness of such measurements in personifying the identity of individuals by forensic anthropologists during mass disasters. Materials and Methods: A cross-sectional, observational study was done using 500 digital OPGs taken with the help of SIRONA Digital Panoramic and Cephalometric System, and specific measurements of mandibular rami were carried out using the SIDEXIS-XG software. The data obtained was subjected to statistical analysis. The determination of sex was done by discriminant function analysis. Statistical Analysis: The data were analyzed using SPSS (Statistical Package for Social Sciences) version 13, SPSS Inc., Chicago, USA. Results: All the variables studied in the present study were found to be significant predictors of sex although variables C, D, and E were found to be highly significant with P values obtained being <0.001. Conclusion: The present study concluded that significant sex-related dimorphism was evident in rami of the mandibles indicating their potential in personifying the identity of individuals during mass disasters.

Keywords: Forensic anthropologists, identity of individuals, mandible, mass disasters


How to cite this article:
Nayyar AS, Kapil F, Sinha P, Borse V, Sirisha K L, Naik PR, Punhani N. Mandible in personifying the identity of individuals in mass disasters: An original study with forensic interest. N Niger J Clin Res 2017;6:21-5

How to cite this URL:
Nayyar AS, Kapil F, Sinha P, Borse V, Sirisha K L, Naik PR, Punhani N. Mandible in personifying the identity of individuals in mass disasters: An original study with forensic interest. N Niger J Clin Res [serial online] 2017 [cited 2022 Oct 5];6:21-5. Available from: https://www.mdcan-uath.org/text.asp?2017/6/9/21/212003




  Introduction Top


The World Disaster Report published by the International Federation of Red Cross and Red Cross Societies in 2012, revealed that the total number of people affected and killed in mass disasters in 2011 itself was around 17 crores and 30 thousands, respectively.[1] The considerably higher number of affected and killed population signifies the role of forensic anthropologists in personal identification during mass disasters. The role of an anthropologist is to create a biological profile of unknown skeletal remains to arrive at conclusions regarding its age, sex, stature, and so on that might lead to personal identification, and for this, even the minutest remains from the body, helpful for identification, should not be neglected. Prediction of sex is one of the leading questions when formulating the biological profile of an individual. Rösing et al.[2] recommended a first evaluation phase by morphologic character before moving on to the second phase of molecular analysis. When soft parts are unavailable, prediction of sex can be based on the characters of the skeleton.[3] Skull is one of the easily sexed portions of the human skeleton. In cases of mass disasters, the entire skull is not readily available for analysis and the technical procedure has to be based on the fragmented bones of the skull. In such cases, mandible plays a vital role in the prediction of sex in an individual.[4],[5] Humphrey et al.[6] found the ramus region of the mandible to be more reliable than the body in the analysis used in forensic anthropological procedures in personifying the identity of individuals during mass disasters. Furthermore, radiographic examination plays a significant role in diagnosing nonaccidental injuries in children, in medical negligence, and in establishing biological aging in the disputed cases.[7] Furthermore, procedures such as digitization of radiographs and computer-assisted image analysis avoid the bias inherent in observer subjectivity and improve reliability, accuracy, and precision. In addition, digital radiographs taken with standard parameters for all patients rule out the possibility of any discrepancy in between the participants. Digital radiography, too, has the lowest possibility of errors due to the magnification factor because of an inherent low and negligible magnification factor inbuilt in their software. Hence, the present study aimed at evaluating the reliability of mandibular rami in personifying the identity of individuals in a selected South Indian population using digital orthopantomographs (OPGs) and purpose the use of same in forensic anthropological procedures during mass disasters.


  Materials and Methods Top


The present study was a cross-sectional, observational study conducted in the Department Of Oral Medicine and Radiology using 500 digital OPGs taken with the help of SIRONA Digital Panoramic and Cephalometric System. The patients had visited the Department for specific complaints and were advised orthopantomographs to either aid their diagnostic process and/or, orthopantomographs were advised to guide their treatment plans. The study population included was a selected South Indian population in the age range of 20–60 years. The study was approved by the Institutional Ethics Committee. Pathological, fractured, and deformed mandibles were excluded from the study. Mandibular rami measurements were carried out using the SIDEXIS-XG software. Radiographs of the patients who were not having pathological, fractured, or deformed mandibles were collected and stored along with their demographic data. Each image was imported into the SIDEXIS-XG software. The tool “Measure Length” was selected in the software and two points were selected using the mouse-driven method between which the length was displayed by the software [Figure 1] and [Figure 2].
Figure 1: Digital orthopantomograph showing mandibular ramus measurements. Variable A: Maximum ramus width: Distance between most anterior and posterior points on the mandibular ramus as represented in the Figure as 1; Variable B: Minimum ramus width: Smallest anteroposterior diameter of the mandibular ramus as represented in the Figure as 2; Variable C: Condylar height/Maximum ramus height: Distance between the most superior point on the condyle to the most protruded point on inferior border of the ramus as represented in the Figure as 3; Variable D: Projective height of ramus: Distance between the most superior point on the condyle to the lower margin of bone on inferior border of the ramus as represented in the Figure as 4; Variable E: Coronoid height: Distance between the most superior point on the coronoid to the most protruded point on inferior border of the ramus as represented in the Figure as 5

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Figure 2: Measurements of mandibular ramus on digital orthopantomograph on monitor using SIDEXIS-XG software

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  • Variable A: Maximum ramus width: Distance between most anterior and posterior points on the mandibular ramus depicted as 1 in [Figure 1]
  • Variable B: Minimum ramus width: Smallest anteroposterior diameter of the mandibular ramus depicted as 2 in [Figure 1]
  • Variable C: Condylar height/maximum ramus height: Distance between the most superior point on the condyle to the most protruded point on inferior border of the ramus depicted as 3 in [Figure 1]
  • Variable D: Projective height of ramus: Distance between the most superior point on the condyle to the lower margin of bone on inferior border of the ramus depicted as 4 in [Figure 1]
  • Variable E: Coronoid height: Distance between the most superior point on the coronoid to the most protruded point on inferior border of the ramus depicted as 5 in [Figure 1].


All the variables obtained were reexamined by two other expert oral radiologists to minimize inter- and intra-observer variability with the value of the Pearson's correlation coefficient (r-value) being 0.98. The data obtained was subjected to statistical analysis. The determination of sex was done by discriminant function analysis. The selected variables of ramus were chosen because of less chances of alteration in these variables with advancing age compared to measurements of the body of the mandible. Furthermore, there are less geometric errors in the images obtained by digital OPGs in the ramus region compared to midline structures of the mandible.

Statistical analysis

The data were analyzed using SPSS (Statistical Package for Social Sciences) version 13, SPSS Inc., Chicago, USA. Discriminant function analysis was used to determine the variables showing discrimination between naturally occurring groups and to determine which variables were the best predictors.


  Results Top


Out of the 500 digital OPGs taken, 271 OPGs were females and 229 were males. Descriptive statistics of mandibular rami measurements and all variables were found to be the best predictors for prediction of sex in the study with Variable C: Condylar height/maximum ramus height; Variable D: Projective height of ramus; and Variable E: Coronoid height, being highly significant, with P values being <0.001. This implies that all variables showed their uniqueness among the individuals considered for the sample, with Variables C, D, and E being highly significant in their uniqueness. The associated univariate F-ratios for both sexes are also shown in [Table 1] and [Graph 1]. Furthermore, it was observed that the mean values were significantly higher in males than females for all variables. All the variables were found to be significant predictors for classifying a given sample based on sex. From the values obtained by linear discriminant function, calculations can be done with the help of the following equations to estimate sex in an unknown sample [Table 2]:
Table 1: Descriptive statistics

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Table 2: Linear discriminant function

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  • Males: 143.277 + 0.805 (maximum ramus width) + 0.538 (minimum ramus width) + 3.532 (condylar height) – 1.294 (projective height of ramus) + 0.833 (coronoid height); and
  • Females: 121.646 + 0.858 (maximum ramus width) + 0.666 (minimum ramus width) + 3.21 (condylar height) – 1.159 (projective height of ramus) + 0.636 (coronoid height).


For classifying a given sample as males or females, the maximum value of two equations is considered. Prediction accuracy was calculated for the study sample. With all the variables in consideration, 80.4% of the sample was classified accurately [Table 3]. Among 271 females in the sample, 228 were estimated correctly as females using the above equations, while in case of males, among 229 males in the study sample, 174 were estimated as males using the above equations with prediction accuracy being 84.1% among females, 76% among males, and 80.4% for the entire study sample. In the present study, sectioning point was found to be 0.19. For any unknown sample, for prediction of sex, we calculate the value obtained from the above-mentioned equations using the five variables obtained from the Sidexis software. If the value is greater than this sectioning point, i.e., 0.19, sample is male, and if the value is lesser than this point that indicates a female [Table 4].
Table 3: Prediction accuracy

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Table 4: Standardized and unstandardized coefficients

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  Discussion Top


Forensic odontology is the study of dental applications in legal proceedings. Recent advances and current trends in forensic odontology include DNA profiling from teeth, palatal rugae and lip print patterns, novel methods of identification of human remains, innovative techniques in bite-mark analysis, contemporary methods for prediction of age and sex, and the role of digital panoramic radiography in forensic odontology. Forensic odontology plays a major role in personifying the identity of individuals in forensic anthropological procedures during mass disasters that result in multiple fatalities that may not be identified by means of conventional methods. One of the crucial aspects of forensic odontology is to predict sex using fragmented jaws as intact skulls are not available for analysis during mass disasters. Prediction of sex based on morphology is subjective and likely to be biased, but methods based on measurements are accurate and can be used in the determination of the same from skull-based measurements that provide a more objective criteria to arrive at such conclusions with a greater degree of accuracy, reliability, and reproducibility.[4],[5] Digital OPGs have been widely used by the clinicians as a screening modality for the diagnosis of a plethora of oral diseases. The major advantages of this specialized radiography include a broad coverage, low patient radiation dose, ease of examination, and a shorter time required to make images. The inherent limitations of orthopantomography, however, include low resolution, lack of fine details with these limitations being common to all extra-oral radiographs, unequal magnification and geometric distortion with overlapping in the pre-molar areas in addition to the masking of lesions, if any, in the midline due to overlap by the dense cervical spine, little alteration in vertical dimensions and the technique being sensitive to a plethora of positioning errors although the said limitations can be overcome to a great extent if a proper technique is followed. In the present study, mandibular rami measurements were subjected to discriminant functional analysis. The selected variables of ramus were chosen because of less chances of alteration in these variables with advancing age compared to measurements of the body of the mandible. Furthermore, there are less geometric errors in the images obtained by digital OPGs in the ramus region compared to midline structures of the mandible.[6] Sidexis software is most widely used nowadays due to its accuracy in measurements. Hence, this software was considered to take the measurements in the present study. In the present study, mandibular rami measurements were subjected to discriminant functional analysis based on the predictability of the results using the same in previous studies.[8],[9],[10] In the present study, all the mentioned variables chosen expressed strong sexual dimorphism with the mandibular rami with strongest univariate dimorphism in terms of condylar height, coronoid height, projective height of ramus, and ramus width (max and min) in that order. Furthermore, the overall prediction rate using all five variables was found to be 80.4%. Similar results were obtained by the studies conducted by Martin,[11] Schulze et al.,[12] Laster et al.,[13] and Razi et al.[14] Giles[9] identified the height of the symphysis, ramus and body region of mandible, the length of mandibular body, and bigonial diameter to be the most useful indicators in the prediction of the sex of individuals. Hanihara[10] did a study on Japanese crania and obtained a high level of accuracy using measurements from the calvarium and mandible for the same. Loth SR et al,[4] also, concluded the same from their study and suggested that the degree of flexure of the posterior border of the ramus was as reliable a morphological indicator for prediction of sex as the pelvis. Suazo Galdames et al.,[5] too, conducted a similar OPG study and concluded mandibular ramus flexure to be a strong morphological indicator in the prediction of sex in young adults in Chile. Furthermore, DNA tests in victims of mass disasters can prove helpful in personal identification but the technique depends on previous medical records for comparison to arrive at specific conclusions. The additional complication of reduced availability of direct reference samples, also, remains a major factor to be dealt with a plethora of factors affecting DNA integrity with time. All these challenges require an approach to the identification process of the victims as an integral effort based on DNA testing as well as forensic anthropological procedures including fingerprints and forensic odontological and radiological procedures wherein forensic odontology and radiology might have a quintessential role to play.[15]


  Conclusion Top


The present study concludes with the observation of the reliability of mandibular rami in personifying the identity of individuals in forensic anthropological procedures during mass disasters. The role mandibular rami can have during mass disasters makes them reliable enough to be included as one of the skeletal indicators for forensic analysis and anthropological procedures, especially, in situ ations where the availability of soft tissues is questionable for analysis.

Limitations of the study

Since numerous studies conducted in the past have demonstrated that skeletal characteristics differ in each population and have emphasized the need for population-specific osteometric standards in the personification of the identity of individuals, the present study paves way for further studies to be conducted on more diverse populations to establish population-specific osteometric standards and deriving appropriate regression equations taking into consideration the numerous factors including the various socioenvironmental factors including nutrition, food, climate, pathologies influencing the development, and thus, the appearance of bones and other factors which might influence the growth patterns to come to valid conclusions. Furthermore, regression equations are not always foolproof. Linear regression is a statistical method for examining the relationship between a dependent and one or more independent variables. It provides a functional relationship between two or more related variables with the help of which the unknown values of one variable can easily be estimated or predicted from the known values of another variable. It, also, provides a measure of errors of estimates made through the regression line. A little scatter of the observed (actual) values around the relevant regression line indicates good estimates of the values of a variable with less degree of errors involved therein and vice-versa. Linear regression, also, provides a measure of coefficient of correlation between the two provided variables; however, despite the above utilities, the technique of regression analysis suffers from numerous serious limitations. Linear regression equations assume that the cause and effect relationship between the variables remains unchanged, though, this assumption might not always hold good, and hence, estimation of the values of a variable made on the basis of the regression equation may lead to erroneous and misleading results.

Acknowledgment

The authors would like to thank all the patients who contributed in the study without whom this study would not have been feasible.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
World Disasters Report. Focus on forced migration and displacement. International Federation of Red Cross and Red Crescent Societies. Geneva: Switzerland: 2012. p.1-310.  Back to cited text no. 1
    
2.
Rösing FW, Graw M, Marré B, Ritz-Timme S, Rothschild MA, Rötzscher K, et al. Recommendations for the forensic diagnosis of sex and age from skeletons. Homo 2007;58:75-89.  Back to cited text no. 2
    
3.
Steyn M, Iscan MY. Sexual dimorphism in the crania and mandibles of South African whites. Forensic Sci Int 1998;98:9-16.  Back to cited text no. 3
    
4.
Loth SR, Henneberg M. Mandibular ramus flexure: A new morphologic indicator of sexual dimorphism in the human skeleton. Am J Phys Anthropol 1996;99:473-85.  Back to cited text no. 4
    
5.
Suazo Galdames IC, San Pedro Valenzuela J, Quezada NA, Contreras CE, Hidalgo Rivas JA, Cantín López M. Orthopantomographic blind test of mandibular ramus flexure as a morphological indicator of sex in Chilean young adults. Int J Morphol 2001;26:89-92.  Back to cited text no. 5
    
6.
Humphrey LT, Dean MC, Stringer CB. Morphological variation in great ape and modern human mandibles. J Anat 1999;195(Pt 4):491-513.  Back to cited text no. 6
    
7.
Kahana T, Hiss J. Forensic radiology. Br J Radiol 1999;72:129-33.  Back to cited text no. 7
    
8.
Press SJ, Wilson S. Choosing between logistic regression and discriminant analysis. J Am Stat Assoc 1978;73:699-705.  Back to cited text no. 8
    
9.
Giles E. Sex determination by discriminant function analysis of the mandible. Am J Phys Anthropol 1964;22:129-35.  Back to cited text no. 9
    
10.
Hanihara K. Sex diagnosis of Japanese skulls and scapulae by means of discriminant function. J Anthropol Soc Nippon 1959;67:191-7.  Back to cited text no. 10
    
11.
Martin ES. A study of an Egyptian series of mandibles with special reference to mathematical methods of sexing. Biometrika 1936;28:149-78.  Back to cited text no. 11
    
12.
Schulze R, Krummenauer F, Schalldach F, d'Hoedt B. Precision and accuracy of measurements in digital panoramic radiography. Dentomaxillofac Radiol 2000;29:52-6.  Back to cited text no. 12
    
13.
Laster WS, Ludlow JB, Bailey LJ, Hershey HG. Accuracy of measurements of mandibular anatomy and prediction of asymmetry in panoramic radiographic images. Dentomaxillofac Radiol 2005;34:343-9.  Back to cited text no. 13
    
14.
Razi T, Moslemzade SH, Razi S. Comparison of linear dimensions and angular measurements on panoramic images taken with two machines. J Dent Res Dent Clin Dent Prospects 2009;3:7-10.  Back to cited text no. 14
    
15.
Fleck F. Tsunami body count is not a ghoulish numbers game. Bull World Health Organ 2005;83:88-9.  Back to cited text no. 15
    


    Figures

  [Figure 1], [Figure 2]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4]



 

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