Digital analysis of linear measurements related to the mental and mandibular foramina in sex determination

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1 Journal of Medicine, Radiology, Pathology & Surgery (2016), 2, 5 9 ORIGINAL ARTICLE Digital analysis of linear measurements related to the mental and mandibular foramina in sex determination Noori Ghouse, Tejavathi Nagaraj, Leena James, Navya N. Swamy, C. D. Jagdish, T.V. Bhavana Department of Oral Medicine and Radiology, Sri Rajiv Gandhi Dental College and Hospital, Cholanagar, Bengaluru, Karnataka, India Keywords Digital panoramic radiographs, forensic, mandible, mandibular foramina, mental foramina Correspondence Dr. Noori Ghouse, Department of Oral Medicine and Radiology, Sri Rajiv Gandhi Dental College and Hospital, Cholanagar, Bengaluru , Karnataka, India. Phone: , noori.gmh@gmail.com Received 01 January 2015; Accepted 06 February 2015 doi: /ins.jmrps.55 Abstract Background: In forensic anthropology, the mental and mandibular foramina are important anatomic landmarks in mandibular region, useful in gender identification in forensic dentistry. Objectives: This study is carried out to predict the validity of the vertical measurements related to the mental and mandibular foramina on digital panoramic images in sex determination. Methodology: A total of 60 patients, 30 males, and 30 females were examined; age distribution was ranging between 20 and 49 years. Four linear vertical measurements were performed on the radiographic image of each subject on both sides of the mandible. Results: Comparison of both sides of mandible was similar with slight discrepancies in measurements, hence any side can be used for analysis, and the means of overall values for D1, D2, D3 and D4 were significantly higher in male than female. According to the analysis, D2 is highly sensitive, D1 highly accurate, D3 highly specific and D4 highly significant. Conclusion: Results revealed differences between the genders in all of the four measurements in this study, therefore these measurements were sensitive parameters to predict male gender and differentiate it from female and hence they could be applied successfully in forensic dentistry. Introduction Identification of human skeletal remains is an important part of forensic analysis. In adult skeleton, sex determination is the first step, followed by age and stature as age and stature are sex dependent. [1] In mass disasters sex determination is based on the available parts of the skeleton and in such cases 100% accuracy is not possible. [1,2] Skull is the most important and dimorphic portion for sex determination after pelvis but in cases where entire skull is not available mandible can play a very important role in sex determination. [3] Determination of males and females and their ethnic groups is based on the morphological characteristics of bone in the field of forensic anthropology. Mandible is the strongest bone and persists in a well preserved state for a long period. [4,5] Hence, the morphological features of the mandible are commonly used by forensic specialists in determining sex. Sex determination from skeletal remains is an important aspect of the osteologic analysis of a given population. [6,7] Due to the stable relation of mental and mandibular foramen with the base of the mandible they are used as a reference in morphometric analysis. [8] Panoramic radiography is a widely used technique because it has the advantage of providing, in a single film, the image of the full mandible with relatively less exposure, time, and cost. This technique can offer information about the localization of anatomic structures vertical and horizontal bony dimensions. [9] Panoramic digital radiography can be applied in forensic medicine with the utilization of portable units. This approach is less time-consuming and allows the extra-oral examination of the dental status. [10,11] Materials and Methods The study sample consisted of 60 patients from both genders, (30 males and 30 females), attending the Department of Oral Medicine and Radiology, referred for digital panoramic radiographs for various purposes. Journal of Medicine, Radiology, Pathology & Surgery Vol. 2:3 May-Jun

2 Ghouse, et al. Digital analysis in sex determination These patients were evaluated according to gender; they were divided into three groups according to age: First group: Subjects from (20-29) years of age (10 males and 10 females); Second group: Subjects from (30-39) years of age (10 males and 10 females); and Third group: Subjects from (40-49) years of age (10 males and 10 females). Patients age ranging were included, 30 males and 30 females, patients without any known systemic diseases were considered. Patients should have no history of any systemic disease that might affect bone metabolism. Any pathology or congenital anomaly in the mandible that could affect the interpretation of the radiographic image was excluded. Methodology Panoramic image was taken for each patient using Sirona digital X-ray machine. All images were examined on the monitor, and the resolution was enhanced to what was considered optimum. The selected radiographic images were used for making linear measurements on images of the mandibular jaw. Four linear vertical measurements (D1, D2, D3, and D4) were performed on all radiographic images according to Amorim et al. [12] These measurements were done on the right and left sides of the mandible image. Measurements were taken on both the sides of the mandible. The following measurements were taken, Figure 1: D1: Vertical distance from the most inferior point on the mental foramen to the inferior most point on the base of the mandible. D2: Vertical distance from the most superior point on the mental foramen to the superior most point of the alveolar crest. D3: Vertical distance from the most inferior point of the mandibular notch to the most superior point on the mandibular foramen. D4: Vertical distance from the most inferior point of the mandibular notch to the inferior edge of the mandibular ramus. Method of statistical analysis The following methods of statistical analysis have been used in this study. Data was entered in Microsoft excel and analyzed using SPSS (Statistical Package for Social Science, Version ) package. Normality of data was tested using Shapiro- Wilk test. The Student s t-test was used to determine whether there was a statistical difference between groups in the parameters measured if the data is normal. Receiver operating characteristic (ROC) analysis was used to assess the validity of linear measurements used in this study in differentiation of male gender from female. A comparison of the diagnostic abilities for each test was performed using the area under the curves. Using the ROC curve the cutoff point was obtained, and sensitivity and specificity were calculated. In all the above test P <0.05 was accepted as indicating statistical significance. Results In the present study, males and females were equally divided into each age group ranging from 20-29, 30-39, and When the comparison of mean values between the right and left side of the mandible was done it was revealed that mean values of right side were almost equal with that on left side justifying that any one side can be used as a unit of sampling as illustrated in Table 1. When comparison of mean values between male and female subjects of the mandible were done, the means of overall values for D1, D2, D3, and D4 were significantly higher in males in comparison to females in all the age groups illustrated in Table 2. Table 1: Comparison of mean difference between right and left side of the mandible Side N Mean SD Minimum Maximum Mean difference SE of difference t value P value D1 (mm) Right * Left D2 (mm) Right * Left D3 (mm) Right * Left D4 (mm) Right * Left SD: Standard deviation, SE: Standard error, P>0.05 not significant 6 Journal of Medicine, Radiology, Pathology & Surgery Vol. 2:3 May-Jun 2016

3 Digital analysis in sex determination Ghouse, et al. Table 2: Mean difference between male and female genders according to age Age (years) Gender N Mean SD Minimum Maximum Mean difference SE of difference t value P value D1 (mm) Male * Female Total D2 (mm) Male Female Total D3 (mm) Male * Female Total D4 (mm) Male *** Female Total D1 (mm) Male <0.001*** Female Total D2 (mm) Male * Female Total D3 (mm) Male * Female Total D4 (mm) Male * Female Total D1 (mm) Male ** Female Total D2 (mm) Male * Female Total D3 (mm) Male * Female Total D4 (mm) Male <0.001** Female Total SD: Standard deviation, SE: Standard error, P>0.05 not significant, P<0.05 significant, P<0.05 highly significant Journal of Medicine, Radiology, Pathology & Surgery Vol. 2:3 May-Jun

4 Ghouse, et al. Digital analysis in sex determination Table 3: Validity parameters for selected cut off values of selected tested parameters when used to predict male gender, differentiating it from female gender AUC P value Cut off value Sensitivity (%) Specificity (%) Accuracy (%) PPV (%) NPV (%) D1 (mm) <0.001*** < D2 (mm) * < D3 (mm) * < D4 (mm) <0.0001*** < AUC: Area under the curve, PPV: Positive predictive value, NPV: Negative predictive value that the verticle measurements from mandibular and mental foramen are potent indicators for sex determination and useful in differentiating male gender from female. Table 3 shows the validity parameters for D1, D2, D3, D4 for a cutoff value to check the sensitivity, specificity, accuracy, positive predictive value and negative predictive value, D1 with a cutoff value of is 80 % accurate and statistically significant, D2 with a cutoff value is 90% sensitive and statistically significant, D3 with a cutoff value of 11.7 is highly specific and statistically significant, D4 with a cutoff value of is 78.3% specific and highly significant. Figure 1: Vertical measurements performed on the radiographic image of the mandible When validity parameters for selected cut-off values of selected tested parameters were used to predict male gender, differentiating it from female gender for D1, D2, D3, and D4, D2 is highly sensitive, D1 highly accurate, D3 highly specific and D4 highly significant [Table 3]. Discussion The mandible is one of the strongest bone in the body and stays in a well preserved state for a long period. Wical and Swoope, [13] Lindh et al. [14] and Güler et al. [15] stated that in spite of resorption of alveolar bone above the mental foramen the distance from a mental foramen to the alveolar crest remains constant. Studies by Morant et al. (1936), Martin (1936), and Hrdlicka (1940) (cited in Humphrey et al. [16] ) on mandible have proved the importance of mandible in sex determination. It was noticed that sexual differences were more in mandibular ramus height proving its significance in sex determination when compared to the body of the mandible. [1] Table 1 shows means of the measurements on both the sides of the mandible which is almost equal with no statistical significance and this was coinciding with the study conducted by Rashid and Ali, [17] Wang et al., [18] Oguz and Bozkir. [19] Earlier studies have proved that the vertical position of the mental foramen was almost symmetrical in both sides. Table 2 shows the measurements of the means of D1, D2, D3, D4 between males and females in all the age groups. The means of D1, D2, D3, and D4 in all the age groups was higher in males and this was coinciding with the studies by Rashid and Ali, [17] Yousue and Brooks, [20] Freitas, [21] Al-Khateeb et al., [22] Amorim et al., [12] Şahin et al., [23] and Kilarkaje et al., [24] Al-Mufti et al., [25] indicating Conclusion Results revealed differences between the genders in all of the four measurements in the present study, and the previous studies conducted by Enlow and Hans [26] explained the differences in measurements in both genders, therefore; these measurements were sensitive parameters to predict male gender and differentiate it from female, so they could be applied successfully in forensic dentistry. Clinical Significance The present study is statistically significant and helps in differentiating male gender from female and can be used for sex determination in forensic dentistry. References 1. Indira AP, Markande A, David MP. Mandibular ramus: An indicator for sex determination - A digital radiographic study. J Forensic Dent Sci 2012;4: Raj JD, Ramesh S. Sexual dimorphism in mandibular ramus of south Indian population. Antrocom Online J Anthropol 2013;9: Acharya AB, Sivapasundaram B. Forensic odontology. Shafer s Textbook of Oral Pathology. 5 th ed. New Delhi: Elsevier; p Thakur M, Reddy KV, Sivaranjani Y, Khaja S. Gender determination by mental foramen and height of the body of the mandible in dentulous patients, a radiographic study. J Indian Acad Forensic Med 2014;36: Hu KS, Koh KS, Han SH, Shin KJ, Kim HJ. Sex determination using nonmetric characteristics of the mandible in Koreans. J Forensic Sci 2006;51: Journal of Medicine, Radiology, Pathology & Surgery Vol. 2:3 May-Jun 2016

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