| Abstract|| |
Background: Mandible is a dimorphic, dense compact bone that makes it very durable and well preserved in mass disasters for personnel identification. Mandibular ramus morphometric measurements can be used for gender determination using orthopantomogram (OPG) or on dry mandibles. Aim: To determine gender from morphometric analysis of mandibular ramus of 200 digital OPG of patients from Sriganganagar population. Materials and Methods: The study was conducted on randomly selected digital OPG of 200 patients of both genders between the ages of 21 and 70 years taken using CS8000C machine from daily OPD. Morphometric analysis of mandibular ramus (maximum ramus breadth, minimum ramus breadth, condylar height, projective height of ramus, and coronoid height) was done twice by single maxillofacial radiologist independently at an interval of 1 day and mean of both the values were considered. The collected data was tabulated and analyzed using SPSS Software version 20 using independent ṯ-test and discriminant function analysis. Results: Out of total 200 subjects, 37% were male and 63% were female. Mean of minimum ramus breadth, maximum ramus height, and projected ramus height was noted significantly more among males while maximum ramus breadth was noted slightly higher in females. The overall accuracy for determining sex from mandibular ramus was found to be 77.6%, whereas for determining male and female, the accuracy was 78.4% and 76.8%, respectively. Conclusion: Mandibular ramus can be used for sexual dimorphism by morphometric analysis done on OPG among Sriganganagar population.
Keywords: Discriminant functional analysis, forensic odontology, panoramic radiographs, sexual dimorphism
|How to cite this article:|
Saloni, Verma P, Mahajan P, Puri A, Kaur S, Mehta S. Gender determination by morphometric analysis of mandibular ramus in sriganganagar population: A digital panoramic study. Indian J Dent Res 2020;31:444-8
|How to cite this URL:|
Saloni, Verma P, Mahajan P, Puri A, Kaur S, Mehta S. Gender determination by morphometric analysis of mandibular ramus in sriganganagar population: A digital panoramic study. Indian J Dent Res [serial online] 2020 [cited 2022 Jan 17];31:444-8. Available from: https://www.ijdr.in/text.asp?2020/31/3/444/291491
| Introduction|| |
Chronological age and gender assessment is an important part of medicolegal practice. The procedures for age determination are complex and involving consideration of many factors. The chronological age-related changes are seen in both dental soft and hard tissues. The facial bones are extremely resistant to fire and are usually the only remains after an extended period of burial. As a result, forensic odontology has gained importance as a tool in identifying the skeletal/dental remains. The present “age-at-death” estimation techniques have limited precision; researchers have sought to demonstrate age-related changes in the dental hard tissues. Now a days, dentofacial radiography has become a routine procedure in many dental, medical, and hospital clinics, where in radiographs are taken at different periods during the lifetime of large segments of the population. The first step in identification process is gender determination on which the subsequent methods for age and stature estimation are dependent., The gender can be determined up to 100% accuracy when the entire adult skeleton is available for analysis. But in cases of mass disasters where usually fragmented bones are found, 100% accuracy of sex determination is not possible. In such situations, pelvis and skull bones are used for sex determination. Skull is the most dimorphic and easily sexed portion of skeleton after pelvis, providing accuracy up to 92%. This is due to difference in growth pattern and maturation rate of skeletal bones which is seen early in females than males. Male bones are generally bigger and more robust than female bones. Humphreyet al. emphasized that almost any site of mandibular bone deposition, or resorption, or remodelling for that matter, seems to have a potential for becoming sexually dimorphic. Hence, mandibular condyle and ramus, in particular, are generally the most sexually dimorphic as they are the sites associated with the greatest morphological changes in size and remodelling during growth. The mandible is the last skull bone to cease growth and is sensitive to the adolescent growth spurt. The mandibular ramus and angle measurements from a dry adult mandible can be used for sex determination. A large number of studies on mandible using metric methods like discriminant function analysis are also available in the literature. So far, among the metric methods conducted in India, the minimum accuracy of sex determination using mandible was 60.3%, 70.9%, and 76%. The radiograph is a noninvasive method, which can be employed in both living and dead individuals. The dental orthopantomogram (OPG) has been used as a valuable tool in forensic science and the accuracy of digital panoramic radiography in providing anatomic measurements has been established. The OPG is commonly used for obtaining a comprehensive overview of the maxillofacial complex. In forensic anthropology, comparison of antemortem and post-mortem radiographs is one of the key features of identification of human remains. Antemortem OPG may be of great value in the identification of human remains. The principal advantages of digital panoramic images are their broad coverage, low patient radiation dose, and short time required for image acquisition. Other advantages are that interference of superimposed images are not encountered. Also the contrast and brightness enhancement and enlargement of images provide an accurate and reproducible method of measuring the chosen points., Hence, the present study was conducted to evaluate the accuracy of sex determination using morphometric analysis of mandibular ramus using digital OPG among Sriganganagar semi-urban population.
| Material and Methods|| |
The present prospective study was conducted in the Department of Oral Medicine and Radiology of a dental college in Rajasthan. The study sample consisted of randomly selected 200 subjects of either gender, between the age of 21–70 years attending the outpatient department of Oral Medicine and Radiology who required OPG for diagnostic purpose. The informed and written consent was taken from each patient and the institutional ethical committee clearance (SDCRI/IEC/2017/010) was obtained before the conduct of study. The subjects were selected based on the following inclusion criteria: (1) The radiographs taken with proper patient positioning and without any magnification errors. (2). No missing tooth in the mandibular arch. (3) OPGs free from pathologies were considered. The exclusion criteria: (1) Patients with endocrinal and systemic disorders. (2) Patients with past history of temporomandibular joint disorders, maxillofacial trauma/surgery. (3) Patients with congenital maxillofacial malformations or syndromes. (4) Poorly visualized radiographs. (5) Pregnant females.
After clinical examination, the subjects satisfying the inclusion and exclusion criteria were subjected to digital panoramic radiography by CS8000C digital OPG/Cephalometric machine under standard exposure factors (73 kVp, 12 mA, 13.9 s) as recommended by the manufacture. A 2 cm, 20 gauge orthodontic metallic wire was placed vertically in the pre-tragus area before doing an OPG, so as to take vertical magnification into consideration [Figure 1]. The morphometric analysis of mandibular ramus (maximum ramus breadth, minimum ramus breadth, condylar height, projective height of ramus, and coronoid height) was done twice by single maxillofacial radiologist independently at an interval of 1 day and the mean of both the values were considered. The parameters were defined as under [Figure 2]:
|Figure 1:Showing (C) patient positioning on digital OPG machine (D) OPG image|
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|Figure 2:Showing morphometric analysis of mandibular ramus on OPG in (a) Male (b) Female|
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- Maximum ramus breadth (MRB): The distance between the most anterior point on the mandibular ramus and a line connecting the most posterior point on the condyle and the angle of jaw.
- Minimum ramus breadth: Smallest anterior--posterior diameter of ramus.
- Coronoid Height: Projective distance between coronoid and lower wall of the bone.
- Condylar/maximum ramus height: Height of the ramus from the most superior point on the mandibular condyle to the tubercle or most protruding portion of the inferior border of the ramus.
- Projective ramus height: Projective height of ramus between the highest point of the mandibular condyle and lower margin of the bone.
The collected data was tabulated and analysed using SPSS Software version 20 (Chicago, SPSS Inc.), and the tests applied were independent t-test and discriminant function analysis.
| Results|| |
The distribution of the subjects showed that out of total 200 subjects, 74 (37%) were male and 126 (63%) were female. The total mean of minimum and maximum ramus breadth was 25.15 ± 4.98 mm and 31.04 ± 3.99 mm, respectively. The maximum and projective ramus height was 65.09 ± 4.68 mm and 56.97 ± 6.03 mm, respectively, while the coronoid height was found to be 56.99 ± 4.41 mm [Table 1].
|Table 1: Discriminant analysis of different parameters of mandibular ramus|
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In the present study, it was distinctly observed that the mean of minimum ramus breadth, maximum ramus height, and projected ramus height was noted more among males while maximum ramus breadth was noted slightly more among females. On applying independent t-test for various parameters between both genders, significant (P < 0.01) higher values were found for males than females for minimum ramus breadth, maximum ramus height, and projected ramus height.
The Box's M statistics was applied to verify the applicability of mandibular ramus in determining gender by using the measurements of above study parameters which showed that male and female can be differentiated and it was significant (P < 0.05). [Table 2]
The accuracy for gender determination was obtained using canonical discriminant function coefficient and constant value from the dimensions of mandibular ramus [Table 3]. The estimated sex can be calculated using the following equations:
For males = −179.799 + (1.23 × minimum ramus breadth) + (0.162 × maximum ramus breadth) + (3.009 × maximum ramus height) + (0.335 × projective ramus height) + (2.301 × coronoid height).
For females = −158.228 + (1.05 × minimum ramus breadth) + (0.392 × maximum ramus breadth) + (2.733 × maximum ramus height) + (0.310 × projective ramus height) + (2.176 × coronoid height). The sectioning point was found to be 0.593. The discriminant function value if near to 0.593, then the person is probably male, whereas if it is near to − 0.593, then the person is probably female [Table 3].
In the present study, out of 74 males, 58 (78.4%) were correctly predicted as males, whereas out of total 126 females, 97 (76.8%) were correctly predicted as females. Thus, it was observed that the overall accuracy for determining sex from mandibular ramus was 77.6% [Table 4].
| Discussion|| |
One of the important aspects of forensics is to determine gender from fragmented dentition and jaws. The sex identification based on morphological marks is subjective and likely to be inaccurate, but measurements and morphology based methods are accurate and can be used in sex determination from skull. The mandibles were used for sex determination during mass disasters for two reasons: firstly there appears to be a paucity of standards utilizing this element and secondly this bone is often recovered largely intact. The sites of mandible where bone remodelling occurs have the maximum potential for becoming sexually dimorphic. Ramus and condyle are usually the most sexually dimorphic because of consistent morphological changes in size and remodelling during the growth.
The accuracy of orthopantomography in providing anatomic measurements has been established. Moreover, OPGs has been used by clinicians as an appropriate screening tool for the diagnosis of oral diseases. The limitations of this technique are magnification and geometric distortion, the vertical dimensions in contrast to the horizontal dimensions is little altered. However, in our study, this limitation did not affect our results since a 2 cm, 20 gauge orthodontic metallic wire was placed vertically in the pre-tragus area before doing an OPG, so as to take vertical magnification into consideration. Usually the gender can be accurately identified after completion of development of concerned bone, hence justifying the present study age group selection of 21-70 years.
In this study, discriminant functional analysis was done to study mandibular ramus measurements. Out of the five mandibular ramus parameters measured from OPG, three variables showed statistically significant (P < 0.05) sex differences between sexes, indicating that ramus expresses good sexual dimorphism. The ramus presented highest univariate sexual dimorphism in relation to maximum ramus height and maximum ramus breadth which are in accordance with the results of Indiraet al., Giles E studies, and Humphreyet al. studies. This is due to the differences related to a different musculoskeletal development and to the differences related to different growth trajectory in males and females. Moreover, the Box's M statistics was done to confirm the applicability of ramus in determining the gender which proved to be significant (P < 0.05) and the results were in accordance with Bhagvan C et al. studies.
In the present study, 78.4% of males and 76.8% females were successfully identified by mandibular ramus morphological analysis on OPG with overall accuracy of 77.6% but the results did not match with Bhagvan Cet al. studies (overall accuracy is 69%) and Indiraet al. studies (overall accuracy is 76%). The reason might be due to small sample size of our study and also due to different populations considered for different studies. It has been established that socioenvironmental factors (nutrition, climate, food, etc.) influence the development and thus the morphology of bones. Many studies, demonstrated that skeletal characteristics differ in each population and have emphasized the need for population-–specific osteometric standards for gender determination.
The limitations of the study are small sample size, inability to determine the sex if the age range is below the age of complete development of mandible, and inability to assess the gender in case of edentulous patients.
| Conclusion|| |
The mandibular ramus can be considered another valuable tool in gender determination with the help of OPG among the studied population. However, further population-specific studies with larger sample are needed to be untaken in the future to substantiate the usefulness of this study.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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Dr. Pradhuman Verma
Department of Oral Medicine and Radiology, Surendera Dental College and Research Institute, H.H Gardens, Power House Road, Sriganganagar - 335001, Rajasthan
Source of Support: None, Conflict of Interest: None
[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4]