Utility of Maxilla-mandibular indices for gender determination by using lateral cephalograms

 

Dr. Suwarna Dangore Khasbage¹, Dr Neha Agrawal², Dr Rahul Bhowate³

¹Professor, Sharad Pawar Dental College and Hospital, Datta Meghe Institute of Medical Sciences

(Deemed to be University), Wardha

²Post Graduate Student, Sharad Pawar Dental College and Hospital, Datta Meghe Institute of Medical Sciences (Deemed to be University), Wardha.

³Professor, Sharad Pawar Dental College and Hospital, Datta Meghe Institute of Medical Sciences

(Deemed to be University), Wardha

 

ABSTRACT:

Background- Gender determination is one of the vital aspects in personal identification as it narrows down the diagnosis towards an accurate possibility. A number of body parts and bones are studied and reported to be useful in detecting the gender for forensic purposes. Objective- To assess the utility of maxilla-mandibular indices for gender determination by using lateral cephalograms. Material and methods- This institutional ethics committee approved retrospective study analyzed 90 randomly selected digital lateral cephalograms. Five linear cephalometric indices: mastoidale to sella-nasion plane (Ma-SN), mastoidale to porion-orbitale plane (Ma-FH), distance between gonion to gnathion (Go-Gn), condylon to gnathion (Co-Gn), condylon to gonion(Co-Gn) were used for gender determination. Statistical significance of linear measurement of Maxillary and Mandibular landmarks in males and females was evaluated by using Mann Whitney test. Results- Lateral cepholograms of 66 female and 24 male were analyzed for gender discrimination. Amongst the two maxillary indices, Ma-SN was observed to be useful, whereas amongst three Mandibular indices, Co-Go and Co-Gn were found to be useful for the analysis of the discrimination of the gender. However, the utility of Go-Gn and Ma-FH was found to be non-significant. Conclusion: Maxilla-mandibular indices like Ma-SN, Co-Go and Co-Gn can be utilied for gender determination by using lateral cephalograms.

 

 

INTRODUCTION:

In medicolegal cases and anthropological research, identification of gender of unknown human remains is one of the most important criterion. There are several methods for a determination of gender using different parameters in skeleton. As skeletal components are made up of hard tissues that can withstand extreme conditions, these are widely used in sex distinction.

 

Differences are there in overall body stature, growth spurts, growth patterns, strength of muscular attachments to the bone, and the presence of bony ridges and processes, thus there are differences exist in the skeletal of the two sexes.^1,2 Amongst skeletal components, one of the methods is the measurement of cranio-facial structures which are relatively indestructible.

 

After death, skeleton is last to decompose, next to the enamel of the teeth, thus provides important information in the identification of gender. It is said that the skeleton, next to the enamel of the teeth, provides important information in the identification of gender, as it is last to decompose after death.³ Though certain skeletal components, like the pelvis and sternum, are widely used in gender determination, these are sometimes recovered in broken or incomplete parts.⁴ So, there is a necessity to use alternate areas of the skeleton for forensic purposes in such cases which include the maxilla, mandible since they are reported to remain intact, irrespective of the severe destruction of the skull and other bones, and can be used for identification of victims.^5,6

 

Radiographs are invaluable tools used in forensic sciences specifically on unavailability of skeletal components.⁷ Actually a number of imaging techniques are used to evaluate anatomy of various oral maxillofacial structures.^8-11 Lateral cephalometry is one amongst these which can be used as an investigation in forensic sciences, It is readily available, cheaper, easier to perform, offers speedy results, repeatable and easily implemented for the forensic examination.¹² Lateral cephalogram reveals architectural and morphological details of the skull, provides additional characteristics and multiple points for comparison on a single radiograph.^12,13 Thus, the present study was conducted to measure, compare and evaluate various maxillary and mandibular radiological landmarks and its relationship to the gender as observed in lateral cephalograms.

 

MATERIAL AND METHODS:

This retrospective study was conducted after obtaining approval from the Institutional Ethics Committee. Sample size comprised of 90 randomly selected digital lateral cephalograms (66 females and 24 males) which were obtained by using Planmeca 2011cc Proline Panoramic unit having teeth in centric occlusion and by following the standard criteria with reference to patient position, film position and exposure parameters. The age of the patients ranged between 14 and 26 years with an average age of 21 years and ranged between 14 and 26 years. The radiographic films were processed by digital method. Ideal lateral cephalograms of completely dentate patients with permanent dentitions only were included for assessment. Patients with the history of trauma, orthodontic treatment or any type of surgery were excluded.

 

The five linear cephalometric variables were derived using a range of cephalometric bony landmarks which include: mastoidale to sella-nasion plane (Ma-SN), mastoidale to porion-orbitale plane (Ma-FH), distance between gonion to gnathion (Go-Gn), condylon to gnathion (Co-Gn), condylon to gonion (Co-Gn). (Figure 1) These variables were measured digitally and recorded in tabular format and analyzed for statistical significance.

 

Figure:1. Photograph of Lateral Cephalogram depicting the parameters used in this study

 

Statistical Analysis:

Statistical significance of linear measurement of Maxillary and Mandibular landmarks in males and females was evaluated by using Mann Whitney test

 

Results:

In this study, lateral cepholograms of 66 female and 24 male were analyzed for gender discrimination by using five maxilla-mandibular indices. Out of total five variables studied, two variables were maxillary and three were mandibular. Amongst the two maxillary variables, one (Ma-SN) was observed to be useful as the results were statistically significant. Amongst three Mandibular variables, two variables (Co-Go and Co-Gn) were found to be useful for the analysis of the discrimination of the gender as shown in table 1 and 2 (p<0.0001). In other words, one variable each of both the jaws (Go-Gn was not reliable for the gender discrimination (Go-Gn and Ma-FH) was not useful.

 

Table:1: Average Linear measurement of Maxillary landmarks in males and females

Table:2: Average Linear measurement of Mandibular landmarks in males and females

 

DISCUSSION:

In forensic sciences, determination of gender is the vital factor which increases the potential for identification of the human remains or missing person by a substantial degree.¹⁴ It is reported that, chances of sex identification are variable based on the availability of skeletal parts. For example, chances of accurate determination of sex are 98% if the skeleton is complete, 90% when only skull, and 95% if pelvic bones are present. While the possibility of determination of sex accurately only 80%, if only the long bones, such as femur, humerus, etc. are available for forensic evaluation.^15-17 Srivastava RK et al¹⁵ suggested that by and large the utilization of long bones for sex determination is beneficial as male long bones tend to be longer and huge than those of the feminine, with a lot of marked muscle attachments.¹⁵ Other studies reported the utility of other skeletal components of human body which are likely to be preserved during mass disasters like that the most indicative regions of the skull in terms of sexual dimorphism are the frontal regions and base of the skull.^18,19

 

The present study assessed utility of the maxilla- manduibular indices for gender determination by using lateral cephalograms. Sexual dimorphism is the expression well defined after puberty, during adolescent years.¹² In the present study, the lower age limit was taken as 14 years and that of upper age limit 26 years. Dhaka P et al²⁰  stated that the female mandible has a higher growth rate between the age of 8–12 years while the male mandible shows faster growth between 13–16 years. Beyond this (i.e., 17–20 years), the growth of both sexes is almost equal.²⁰

 

According to Paiva²¹ and Kemkes²² Ma-Sn and Ma-Fh both maxillary parameters were found to be strong contributors for gender discrimination but in present study, Ma-Sn is only found to be significant from maxillary parameters. Results of the present study are consistent with the findings that mean of all the linear measurements of both the maxillary and mandibular parameters were greater in males as compared to females.

With reference to mandibular indices, findings of the present study are comparable to study by  Missier MS et al.²³ They have tested 99 variables, amongst which twenty-four variables showed statistical significance. Ramus length, Condylion to Gnathion (Co-Gn) and ramus height showed the highest sex determining dependability of 78%. In the present study also, Co-Go and Co-Gn were found to be useful for the analysis of the discrimination of the gender. However, according to Naikmasur et al²⁴ other skeletal parts contributed most for sexual dimorphism which includes bizygomatic width, ramus height and depth of the face. According to Shiva Kumar B and Deepthi BC²⁵ coronoid height and the mental index can be used in identification of sex effectively while in elderly,  maximum and minimum breadth of ramus of the mandible is useful for sex determination. Naikmasur et al²⁴ and Hsiao et al¹⁸ presented 80-100% of accuracy by using lateral cephalogram. While inherent magnification is also present in lateral cephalogram along with the parameters.

 

Taken as a whole, findings of the study showed that maxilla-mandibular indices like Ma-Sn, Co-Go and Co-Gn are useful for gender determination by using lateral cephalograms, findings are comparable to previous studies.^12,23,24 Limitation of the study was small sample size.

 

To conclude Maxilla-mandibular indices like Ma-Sn, Co-Go and Co-Gn are useful for gender determination by using lateral cephalograms.

 

ACKNOWLEDGMENTS:

We thankful to Datta Meghe Institute of Medical Sciences (Deemed to be University) for providing the facilities to carry out this research work.

 

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Accepted on 21.01.2020           © RJPT All right reserved

Research J. Pharm. and Tech 2020; 13(9):4175-4178.