Sex determination is a fundamental aspect of forensic anthropology, crucial for the identification of individuals in medico-legal investigations, archaeological studies, and mass disaster scenarios. The human mandible, being the largest and strongest bone of the facial skeleton, exhibits significant sexual dimorphism, making it a valuable tool for sex determination (1). The morphology of the mandibular ramus, in particular, has been recognized as a reliable indicator due to its robustness and resistance to postmortem changes (2,3). Previous studies have demonstrated that parameters such as ramus height, maximum ramus width, minimum ramus width, condylar height, and coronoid height can effectively differentiate between male and female mandibles (4). These measurements are known to be influenced by genetic, environmental, and functional factors, resulting in distinct differences between sexes (5).

Research focusing on various populations has reported varying degrees of accuracy in sex determination based on mandibular ramus morphology. Studies conducted on Indian populations have shown promising results, with accuracy rates ranging from 75% to 90% depending on the parameters evaluated and statistical methods applied (6,7). However, limited literature exists concerning the comprehensive evaluation of multiple mandibular ramus parameters in a large sample size of the Indian population.

The present study aims to evaluate the sexual dimorphism of the mandibular ramus in the Indian population and determine the efficacy of different parameters for accurate sex determination. Additionally, this study seeks to enhance the existing knowledge base and provide a reliable method for forensic and anthropological applications

Study Design and Sample Size:

This retrospective study was conducted using 200 orthopantomographs (OPGs) collected from OPD and radiology departments. The sample consisted of 100 males and 100 females, aged between 20 to 50 years, all of Indian origin. The inclusion criteria included high-quality radiographs with clearly visible mandibular rami. Radiographs with deformities, fractures, or pathological conditions affecting the mandible were excluded.

Data Collection and Measurements:

Digital orthopantomographs were evaluated using standardized software (e.g., AutoCAD or ImageJ) for accurate measurements of the mandibular ramus. The following parameters were measured bilaterally:

1. Ramus Height: The distance from the most superior point of the condyle to the lower border of the mandible.
2. Maximum Ramus Width: The greatest horizontal distance between the anterior and posterior borders of the ramus.
3. Minimum Ramus Width: The narrowest distance between the anterior and posterior borders of the ramus.
4. Condylar Height: The distance from the most superior point of the condyle to the gonion.
5. Coronoid Height: The distance from the most superior point of the coronoid process to the gonion. (Figure 1,2)

Figure 1: CBCT scan of the mandible

Figure 2: landmarks on the mandible

Each parameter was measured three times by two independent observers to minimize observational bias. The mean of the three measurements was considered for analysis.

 Statistical Analysis:

Data were statistically analyzed using SPSS software (version 26). Independent t-tests were employed to compare mean values between males and females for each parameter. Discriminant function analysis was applied to evaluate the accuracy of sex determination based on mandibular ramus morphology. The level of significance was set at p < 0.05.

 Reliability Testing:

The reliability of the measurements was assessed using the Intraclass Correlation Coefficient (ICC), ensuring consistency and reproducibility of the results.

The study evaluated mandibular ramus morphology for sex determination using 200 orthopantomographs (100 males and 100 females). Measurements included ramus height, maximum ramus width, minimum ramus width, condylar height, and coronoid height. The data obtained were analyzed to determine significant differences between male and female mandibles.

Comparison of Mandibular Ramus Parameters

Independent t-tests revealed statistically significant differences between males and females across all parameters (p < 0.05). Mean values and standard deviations for each parameter are presented in

Table 1: Comparison of Mandibular Ramus Parameters between Males and Females

As shown in Table 1, the mean values for all parameters were higher in males compared to females. The most pronounced difference was noted in ramus height, which demonstrated a significant difference between the sexes (p < 0.001).

 Discriminant Function Analysis

Discriminant function analysis was performed to assess the accuracy of sex determination based on the measured parameters. The model correctly classified 82.5% of the individuals, with a higher accuracy rate in males (85.0%) compared to females (80.0%).

Table 2: Discriminant Function Analysis for Sex Determination

The analysis (Table 2) indicates that ramus height contributes most significantly to the discriminant function, followed by condylar height and maximum ramus width.

The present study aimed to evaluate the efficacy of mandibular ramus morphology as a reliable tool for sex determination in the Indian population. The findings demonstrated significant sexual dimorphism in all measured parameters, including ramus height, maximum ramus width, minimum ramus width, condylar height, and coronoid height. These results are consistent with previous studies that have identified the mandible as a sexually dimorphic bone due to its robustness and resistance to degradation (1,2).

Ramus height was the most significant parameter contributing to sexual dimorphism, which agrees with findings by Indira et al. (3) and Kanchan et al. (4). Male mandibles exhibited higher mean values for all parameters compared to females, a trend that has been consistently reported in various population-based studies (5,6). This difference can be attributed to the greater muscle attachment area and the overall robusticity of the male mandible, which is functionally adapted to higher masticatory forces (7).

The present study demonstrated an overall classification accuracy of 82.5% using discriminant function analysis. This finding is similar to studies conducted on South Indian and Turkish populations, which reported accuracy rates ranging from 75% to 85% (8,9). The accuracy of sex determination based on mandibular ramus morphology appears to vary depending on population-specific factors, including genetic background, environmental influences, and dietary habits (10).

Condylar height and maximum ramus width were also found to be significant indicators of sexual dimorphism. These parameters have been previously highlighted by Franklin et al. (11) and Ghosh et al. (12) as useful criteria for sex determination. Moreover, the coronoid height, although less reliable than other parameters, still contributed to the overall discriminative power of the analysis (13).

The findings of this study are consistent with previous research conducted on various populations, including Greeks (14), South Africans (5), and Egyptians (6). However, it is essential to recognize that the degree of sexual dimorphism can vary among different ethnic groups. Therefore, population-specific standards should be established to enhance the reliability of forensic identification methods (7).

One of the limitations of this study is the relatively small sample size, which may affect the generalizability of the findings. Future studies should consider larger and more diverse samples to validate the results further. Additionally, the use of advanced imaging techniques, such as three-dimensional (3D) imaging, may improve the accuracy of sex determination by providing more precise measurements (8,9).

The reliability of measurements in this study was ensured through repeated measurements by independent observers, with satisfactory intra- and inter-observer reliability. The use of discriminant function analysis proved to be a valuable statistical tool for developing a predictive model for sex determination, as reported in earlier studies (2).

In conclusion, the present study confirms that mandibular ramus morphology is a useful tool for sex determination in the Indian population, with high accuracy achieved through discriminant function analysis. Further research is needed to establish standardized protocols and reference data specific to various populations to improve the accuracy and applicability of this method

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