Mandibular Ramus Flexure Research Articles

Quantifying Sexual Dimorphism by Analyzing Ramus Flexure and Bigonial Width in Orthopantomography.

Introduction The mandible constitutes one of the skull's largest and strongest bones. Growth spurts can influence it, and it has a variety of dimorphic traits that can be used to identify sex. In addition to observing, comparing, and evaluating the potential for mandibular ramus flexure and bigonial breadth to discriminate between sexes using digital orthopantomograms (OPG), a retrospective study was conducted to examine the validity of this method for sex estimation in the Indian population. Aim and objective This study aims to quantify sexual dimorphism by analyzing two mandibular parameters, the ramus flexure and the bigonial width, using orthopantomography (OPG). The objective is to determine the accuracy of sex determination using the ramus flexure and bigonial width. Materials and methods A total of 500 OPG images (250 males and 250 females) were analyzed using the Planmeca software (Helsinki, Finland). The ramus flexure was measured as the angle formed between the tangent to the inferior border of the mandible and the tangent to the posterior border of the ramus. The bigonial width was measured as the distance between the left and right gonion points. A statistical analysis was performed to assess sexual dimorphism and determine the accuracy of sex determination using these parameters. The study employed descriptive statistics, such as means and standard deviations, and an independent t-test to determine the significance of the characteristics in relation to males and females. Results The mean bigonial width for females was 193.3068 mm (SD = 13.51669 mm) and for males was 217.6308 mm (SD = 10.87453 mm), with a statistically significant difference (p = 0.000). The 95% confidence interval for the difference in the bigonial width between males and females was between -49.97173 mm and -43.93787 mm. For the ramus flexure, the mean was 0.0000 for both males and females (SD = 0.00000), with a significant difference between males and females (p = 0.003). The 95% confidence interval for the difference in the ramus flexure between males and females was between -0.59543 and -0.12457. Conclusion The results indicated significant sexual dimorphism in both the ramus flexure and bigonial width. This study demonstrated that the ramus flexure and bigonial width, measured using orthopantomography (OPG), exhibited significant sexual dimorphism. The analysis of these mandibular parameters provided valuable information for sex determination in forensic and anthropological contexts.

Morphology of mandible - A two year digital radiographic study

Mandible is a unique single bone often recovered intact during mass disasters.To assess whether the specific morphological characteristics of mandible in males and females can be used as an aid for sex determination based on radiographs.A two-year retrospective study was conducted in 200 subjects [100 males and 100 females] using digital radiographs. Profile of chin and morphologic differences in the base of the mandible were assessed using digital lateral cephalogram. Mandibular ramus flexure was assessed from digital Orthopantomogram. The obtained data statistically analysed using SPSS software version 20. Descriptive statistics was analysed. Chi square test was done to determine the association between gender and different parameters. The level of significance set at p ≤ 0.05.There is a significant association between chin profile, base of mandible and mandibular ramus flexure with gender. Females have prominent chin compared to males. Males have undulating base of mandible while females have straight base of mandible. Mandibular ramus flexure in males seen at the level of occlusal plane while it is seen above the occlusal plane in females.There is a morphological difference in the mandible of the males and females.

Predictive accuracy of mandibular ramus flexure as a morphologic indicator for gender determination: A radiographic study

Introduction: In forensic medicine, the identification of age and gender is an initial step and it plays a vital role in determining one's identity. The skeletal components most often investigated for gender determination are pelvis and skull, with the mandible being a practical element to analyze sexual dimorphism in the fragmented bones. Mandibular ramus can be used to differentiate between sexes and it also expresses strong univariate sexual dimorphism. Aim: Determination of gender by using mandibular ramus posterior flexure. Materials and Methods: A radiographic retrospective study was conducted on 25 male and 25 female Orthopantomographs taken in the Department of Oral Medicine and Radiology. Strict exclusion criteria were applied in selecting images. The images were taken using digital panoramic x-ray machine ORTHOPHOS – XG5-Sirona Dental System, Germany (68kvp, 8ma, 14.1 s). To process the images and mark, the location for analysis SIDEXES software was used. Each image was examined for the presence of a flexure on the posterior border of the ramus, which was carefully delineated and the occlusal plane marked, guided by the height of cusp tips of the mandibular molars. Results: In the present study, we observed the overall accuracy using mandibular ramus posterior flexure was 64% in the determination of gender with P = 0.0032. The predictive accuracy was higher for females compared to males. Conclusion: Mandibular ramus flexure can be considered as supplementary rather than definitive mean of sex determination. Hence, it is better to include as many parameters as possible for attaining the accuracy.

Sex estimation through mandibular ramus flexure using Orthopantomogram and Lateral Cephalogram-A comparative study

Mandible is one of the largest and strongest bones in skull. It is sensitive to adolescent growth spurt and holds many dimorphic traits that could be useful for the sex estimation. A retrospective study was done to analyse the reliability of mandibular ramus flexure for sex estimation in Indian population and to observe, compare and evaluate the sex discriminant potential of mandibular Ramus flexure by using digital Orthopantomogram (OPG) and Lateral Cephalogram (LC). The study was conducted on 200 samples (90 males and 110 females) with aged 10–30 years, by using both standard digital OPG and LC for each study sample. The radiographs were visualized using Planmeca Romexis software 2.9.2.R. A tangent line was drawn on the posterior margin of ramus and the orientation line were drawn on the occlusal plane on mandibular molars extended to the ramus body, which predicted the sex by viewing distinct ramus flexure and later compared with actual sex. Sex was accurately determined in 60 out of 90 males with a prediction accuracy rate of 67.4%. 90 out of 110 females were identified correctly with a prediction accuracy rate of 81%. The overall accuracy rate was 74.25%. Similar results were obtained from both OPG and LC analysis. The result of the present study proved that the mandibular ramus plays a major role in sex determination due to its unique high sexual dimorphism. Hence, we advocate the use of mandibular ramus flexure as an aid for sex estimation by using either OPG or LC.

Determination of gender by using mandibular flexure – A radiographic study

Introduction: In forensic medicine identification of age, gender is an initial step in determining one's identity. After the pelvis, mandible plays an important role in determining gender when the whole body is not present. Forensic dentists require knowledge encompassing a number of disciplines since the dental records obtained can identify an individual or afford the information needed by the authorities to establish neglect, fraud, or abuse. Aim: Determination of gender by using mandibular ramus flexure. Materials and Methods: The study was conducted on 50 male and 50 female orthopantomographs taken in the Department of Oral Medicine and Radiology. Each image was examined for the presence of flexure on the posterior margin of the ramus at the occlusal plane. The posterior margin of the ramus was carefully traced graphically and the occlusal plane level was delineated as guided by the height of cusp tips at the occlusal surfaces of the mandibular molars. Results: In the present study, it was proved 64% accuracy in determination of gender with P value of 0.005. Conclusion: By using ramus flexure, sex can be determined moderately and can be used as a supplementary in determining the sex.

Predictive Accuracy of Mandibular Ramus Flexure as a Morphologic Indicator of Sex Dimorphism in Jordanians

El presente estudio investigo la validez de flexura de la rama mandibular en la diferenciacion sexual entre adultos jovenes jordanos utilizando imagenes de ortopantomografias, en un estudio doble ciego. Se selecciono una muestra normativa compuesta de 419 imagenes, de las cuales 126 pertenecian a hombres y 293 a mujeres. Se excluyeron imagenes que mostraron una perdida marcada de los molares mandibulares, dientes sobre erupcionados o inclinados, molares anomalos y los dientes o mandibulas con enfermedad. Cada imagen fue examinada para detectar la presencia de un angulo en el margen posterior de la rama en el plano oclusal. El margen posterior de la rama mandibular fue trazado graficamente y el plano oclusal se delineo estableciendo como guia la altura de las puntas cuspideas en las superficies oclusales de los molares mandibulares. La flexura de la rama mandibular fue mas precisa en el diagnostico de las mujeres (94,6%) que para los hombres (47,6%); con una precision diagnostica global del 70,9%, la cual es inferior a la reportada por Loth & Henneberg entre 90,6­99,0%. Nuestros resultados, concuerdan con algunos hallazgos reportados por otros investigadores. En conclusion, la flexura de la rama mandibular proporciona una exactitud de prediccion moderadamente aceptable y podria ser considerada como un complemento en lugar de un medio definitivo de la determinacion del sexo. En restos oseos desconocidos, es necesario emplear la mayor cantidad de metodos o rasgos posibles que depender de un solo rasgo morfologico.

Sex determination from the mandibular ramus flexure of Koreans by discrimination function analysis using three-dimensional mandible models

It has been known that mandible ramus flexure is an important morphologic trait for sex determination. However, it will be unavailable when mandible is incomplete or fragmented. Therefore, the anthropometric analysis on incomplete or fragmented mandible becomes more important. The aim of this study is to investigate the sex-discriminant potential of mandible ramus flexure on the Korean three-dimensional (3D) mandible models with anthropometric analysis. The sample consists of 240 three dimensional mandibular models obtained from Korean population (M:F; 120:120, mean age 46.2y), collected by The Catholic Institute for Applied Anatomy, The Catholic University of Korea. Anthropometric information about 11 metric was taken with Mimics, anthropometry libraries toolkit. These parameters were subjected to different discriminant function analyses using SPSS 17.0. Univariate analyses showed that the resubstitution accuracies for sex determination range from 50.4 to 77.1%. Mandibular flexure upper border (MFUB), maximum ramus vertical height (MRVH), and upper ramus vertical height (URVH) expressed the greatest dimorphism, 72.1 to 77.1%. Bivariate analyses indicated that the combination of MFUB and MRVH hold even higher resubstitution accuracy of 81.7%. Furthermore, the direct and stepwise discriminant analyses with the variables on the upper ramus above flexure could predict sex in 83.3 and 85.0%, respectively. When all variables of mandibular ramus flexure were input in stepwise discriminant analysis, the resubstitution accuracy arrived as high as 88.8%. Therefore, we concluded that the upper ramus above flexure hold the larger potentials than the mandibular ramus flexure itself to predict sexes, and that the equations in bivariate and multivariate analysis from our study will be helpful for sex determination on Korean population in forensic science and law.

Sex determination using mandibular ramus flexure: A preliminary study on Indian population

Determination of sex by morphological assessment has been one of the oldest approaches in forensic anthropology. Loth and Henneberg 6 introduced a morphological trait “Mandibular Ramus Flexure” for sex identification with a high accuracy of 99% in African Blacks. However, the population specificity of sexually dimorphic features is well known. The purpose of this study is to test the reliability of this trait in Indian population. A total number of 112 adult mandibles (88 males and 24 females) were studied from the Department of Forensic Medicine, Institute of Medical Sciences, Banaras Hindu University, India. The mandibles were scored according to the original method by two observers in three different sessions. This was done to test inter and intra-observer errors in identifying the trait. The result shows that this trait can be used to diagnose sex with an average accuracy of upto 82%. Though, inter and intra-observer errors were present but could be minimized with extended practice. So, the trait has the potential to be relied upon as a single morphological trait for determination of sex in Indian population.

Ortopantomographic Blind Test of Mandibular Ramus Flexure as a Morphological Indicator of Sex in Chilean Young Adults

Loth & Henneberg (1996) describieron un sencillo indicador morfologico para la determinacion del sexo, mediante la observacion de una flexura en el borde posterior de la rama mandibular, a nivel del plano oclusal. El proposito de este estudio fue analizar el nivel de concordancia para la determinacion del sexo, mediante la observacion de parametro descrito por Loth & Henneberg, en ortopantomografias de sujetos adultos jovenes, chilenos, completamente dentados. Se utilizaron 188 ortopantomografias de los archivos del Servicio de Radiologia de la Escuela Dental de la Universidad de Talca, Chile. En nuestro estudio, las ortopantomografias de mujeres fueron clasificadas correctamente en un 63,25% de los casos (62-64,5%); para los hombres, la prediccion de exactitud solo fue de 48,25% (46,5 -50%). Los porcentajes de acierto fueron inferiores a los comunicados por Loth & Henneberg, lo que justifica la necesidad de evaluar los metodos de analisis en antropologia forense que se utilizan en nuestra poblacion.

Predictive accuracy of sexing the mandible by ramus flexure

Loth & Henneberg (Am J Phys Anthrop 99 (1996) 473) described a single morphological indicator of sexual dimorphism, namely the presence or absence of flexure on the posterior border of the mandible, with a predictive accuracy of 90.6–99.0%. In the other studies, which have criticized mandibular ramus flexure as sex indicator in adult and fossils specimens by the same method, the accuracy of sexing was found between 59.0% and 80.4% which is well below the reported 90.6–99.0% (Am J Phys Anthrop 107 (1998) 363; Am J Phys Anthrop 111 (2000) 573; Am J Phys Anthrop 111 (2000) 429; Homo 53 (2002) 97). It was indicated that the method sexed males more reliably than females and consistency was low. In the current blind test, 120 mandibles from forensic cases were examined for the presence or absence of mandibular ramus flexure. Virtually identical results were obtained when a second observer examined the same sample of mandibles. The results were then compared to records of the same cases resulting in 85.8% accuracy for the total sample. A marked difference was observed between sexes where the ramus shape was diagnostic for 92.6% of the males but for only 60.0% of the females ( p< 0.001). When mandibles with excessive tooth loss (more than two molars missing) ( n = 35 ) were removed from the sample (in normative sample), the overall predictive value increased to 90.6% (95.6% accuracy in males and 70.6% in females). Our results confirm that there are marked differences between the sexes in the predictive accuracy and this indicator is better in mandibles without molar tooth loss as mentioned by Loth & Henneberg. They also pointed out that the tooth loss is a potential source of error. On the other hand, in this study, there were no sexing errors when mandibles which ramus shape scores −1, 0 and +1 were extracted from the normative sample as the “sex indeterminate group”. This study suggests that further assessment should be made only when both rami are available for observation, and the mandible shows either bilateral flexure (+2) or bilateral non-flexure (−2). The consideration of this new categorization can also be useful when using Loth & Henneberg's method.

Investigation into the usability of geometric morphometric analysis in assessment of sexual dimorphism

Understanding sexual dimorphism is very important in studies of human evolution and skeletal biology. Sexual dimorphic characteristics can be studied morphologically and metrically, although morphologic studies pose several problems such as difficulties with quantification and interobserver error. Geometric morphometrics is a relatively new method that allows better assessment of morphologic characteristics. This paper aims to investigate the usability of this method by assessing three different morphologic characteristics in a sample of South African blacks: shape of the greater sciatic notch, mandibular ramus flexure, and shape of the orbits. Relative warps, thin-plate splines, and canonical variates analysis (CVA) analyses were performed. As expected, the shape of the greater sciatic notch provided the best separation between the sexes. Surprisingly, however, the shape of the orbits performed better that ramus flexure. Several possible explanations for this result are possible, which include the possibility that orbit shape is more sexually dimorphic than previously expected, or that biological reality is not reflected by this technique. More research is, however, needed.

Mandibular ramus flexure and gonial eversion as morphologic indicators of sex

Recently, two mandibular traits--ramus flexure and gonial eversion--have come under close scrutiny (Loth & Henneberg 1996, 2000). The present study investigates the reliability of these two traits when each is applied as a single and independent indicator of sex, including the question of repeatability. The investigation was designed to give insights into possible confounding factors such as age and remodeling after tooth loss. Two samples, one of forensic (N = 153) and one of archaeological provenance (N = 80), were examined. The forensic sample was evaluated by a single observer while the archaeological sample was independently scored by three different observers. The results document that age and localized tooth loss seriously reduce the accuracy of these traits. For ramus flexure, male accuracy was only 66%, while female accuracy was even lower (32%). Overall accuracy was 59%. It is believed that the original scoring system devised by Loth and Henneberg (1996) creates an inherent bias in favor of males. For gonial eversion, a similar picture emerged (75.4% for males, 45.2% for females and 69.3% overall accuracy). Furthermore, both indicators are prone to intra- as well as inter-observer bias. While both possess some merit as sex indicators, they show marked functional and adaptive responses and may not be suitable for all samples.

Technical note: evaluating mandibular ramus flexure as a morphological indicator of sex.

Described as a highly reliable method of sex identification, mandibular ramus flexure is a morphological trait expressed on the posterior border of the ramus at the occlusal plane (Loth and Henneberg [1996] Am. J. Phys. Anthropol. 99:473-485). In a blind test, 158 mandibles were examined for the presence of flexure as defined by Loth and Henneberg, resulting in 79.1% accuracy, which is well below the reported 91-99% accuracy. Twenty-five of these mandibles were assigned the ambiguous score of 0, an outcome of a +1 score for one side, and a -1 score for the other. Seventeen mandibles were examined twice to measure intraobserver error. Only 64.7% of the scores were duplicated in the second session, suggesting difficulty in consistent identification of flexure. Low overall accuracy, an invalid scoring system, and high intraobserver error indicate that mandibular ramus flexure is an unreliable technique for estimation of sex.

Brief communication: A study of the predictive accuracy of mandibular ramus flexure as a singular morphologic indicator of sex in an archaeological sample

Brief communication: A study of the predictive accuracy of mandibular ramus flexure as a singular morphologic indicator of sex in an archaeological sample

Brief communication: A study of the predictive accuracy of mandibular ramus flexure as a singular morphologic indicator of sex in an archaeological sample

Loth and Henneberg ([1996] Am J Phys Anthropol 99:473-485) assert that they have discovered a single morphologic indicator of sexual dimorphism in the human mandible that rivals the predictive accuracy of the complete pelvis at 94.2% for all samples (99% for healthy samples). To test the accuracy of their method, mandibles (n = 150) from the Tepe Hissar collection were assessed for the presence or absence of mandibular ramus flexure. These results were then compared to a separate sex assessment based on morphologic indicators from the corresponding skull and innominates (where possible) to yield an overall accuracy of only 78.2%. As a means of independent assessment, the mandibular results were also compared with Krogman's ([1940] Racial Types from Tepe Hessar, Iran, from late fifth to early second millennium, BC. Amsterdam: Koninkliijke Nederlandsche Akademie van Wetenschappen) assessment of sex based on craniofacial measurements and morphologic indicators from the skull. This comparison produced an even lower accuracy of 67.2%. Such results question the predictive potential of mandibular ramus flexure as a single indicator of sexual dimorphism and suggest caution when applying this method, especially in the case of fragmentary forensic and fossil remains.

Technical note: a blind test of mandibular ramus flexure as a morphologic indicator of sexual dimorphism in the human skeleton

Loth and Henneberg (1996, Am. J. Phys. Anthropol. 99:473-487) identified a single morphological feature of the mandible, the presence or absence of a distinct flexure or angulation of the posterior margin of the mandibular ramus at the level of the occlusal plane, which appears to be an extraordinarily accurate predictor of sex. Using only this feature, Loth and Henneberg were able to predict sex with 94% accuracy in a large sample of mandibles. In this article, we report the results of a blind test of mandibular ramus flexure as a predictor of sex. In our blind test, only 62.5% of the mandibles were correctly sexed, and virtually identical results were obtained when the same sample of mandibles was examined by a second observer. Overall, our results demonstrate that: 1) the association between ramus flexure and sex is weak; 2) the predictive accuracy of Loth and Henneberg's method is better than chance for only one sex, males; and 3) the method is based on a trait that cannot be reliably or consistently identified.

Mandibular ramus flexure is a good indicator of sexual dimorphism

Mandibular ramus flexure is a good indicator of sexual dimorphism

Mandibular ramus flexure—indicator of sexual dimorphism?

Mandibular ramus flexure—indicator of sexual dimorphism?

Mandibular ramus flexure: A new morphologic indicator of sexual dimorphism in the human skeleton

Mandibular ramus flexure: A new morphologic indicator of sexual dimorphism in the human skeleton