Gender Determination

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MC Supplement - 2012 ( 52 - 54 ) Mirza H. F. et al

GENDER DETERMINATION USING CANINEMANDIBULAR INDEX, A NEW PERSPECTIVEIN FORENSIC ODONTOLOGY

ABSTRACT

The objective of this study was to evaluate the effectiveness of mandibular canine index(MCI) in determination of sex. Possibly the dimorphism of the canines may be used asa valid tool in the forensic and legal identification of an individual. This study comprisedof 89 individuals and 77 cases were enrolled in the study from Pakistan (39 males, 38females) and 12 from UK (8 males and 4 females). Alginate impressions of mandibulararch were also made and the parameters considered were canine width,intercanine distance and mandibular canine index.It was seen that a definite statistically significant sexual dimorphism exists in mandibularcanines. With standard MCI, it was possible to detect sex in the sample studied to anextent of about 76%. Hence it is considered as a quick, easy and reproducible methodfor determining the sex of an individual.

Key Words : Mandibular canine width, Canine index, Intercanine distance, Sex determination.

INTRODUCTION:Identification of skeletal remains has great importance in the field of forensic medicine1.Various methods have been devised to assist the forensic experts in determining thegender of the deceased. Anatomical structures including skull, teeth and pelvic girdle havebeen implicated time and again by the forensic anthropologists to conclude the genderof skeletal remains2.Teeth measurements are significantly authentic tool in determination of gender3 especiallyin cases where secondary sexual characteristics have either not developed or wherecertain body parts, otherwise useful to determine the gender, were missing. Teeth,especially the canines, are the hardest and chemically most stable tissues. They arepresent even in severely decomposed bodies making them very important for identification.The size of the teeth is of great importance, to establish sexual dimorphism. Out of thetwo proportions, width and length, the former is considered to be more important4,5,6.A study from Sweden employed odontometrics to analyze the gender differences. In thisstudy, Lund et al reported males to have larger mesio-distal, bucco-lingual, mesiobuccal-distolingual and distobuccal-mesiolingual diameters7. Another study from Turkey alsoreported significant gender differences using diagonal teeth measurements, where maleswere found to have greater diagonal measurements8.Rao et al in 1989 conducted a preliminary study in India that brought about a newadvancement in the forensic anthropology6. They introduced mandibular canine index(MCI) as a measure for gender ascertainment. It was a very significant as well as a simpleand economical method and has been further worked upon in several studies.Sexual dimorphism refers to the differences in size, stature and appearance between maleand female. This can be applied to dental identification also because no two mouths arealike. Various features like tooth morphology and crown size are characteristic for malesand females. However, tooth morphology is also known to be influenced by cultural,

M E D I C A LM E D I C A LM E D I C A LM E D I C A LM E D I C A LC H A N N E LC H A N N E LC H A N N E LC H A N N E LC H A N N E L

Original Article

ARCHIVES OFSURGERY AND ALLIED

1. FARHAT HUSSAIN MIRZA2. M. MUSAAB SIDDIQUI3. AKHTAR AMIN MEMON4. M. YASIN BANDUKDA5. SYEDA EZZ-E-RUKHSHAN ADIL6. HUMAIRA AMIN

1. Associate Professor and Head,Department of ForensicMedicine,Dow Medical College,Dow University of Health Sciences,Karachi, Pakistan.

2. Postgraduate student,Queen Mary University of London,United Kingdom.

3. Medical student,Dow Medical College,Dow University of Health Sciences,Karachi, Pakistan.



6. Medical studentKarachi Medical and Dental College,University of Karachi, Karachi,Pakistan.

Corresponding Author-CAPT DR FARHAT HUSSAIN MIRZAHead, Department of Forensic MedicineDow University Of Health SciencesDow Medical College, Karachi.Email- [email protected] Address-19-D, Mohammad Ali Housing Society,Miran Mohammad Shah Road, KarachiMob- 03009230198



environmental, and racial factors9. Variation in tooth form can bestudied by measurement of enamel height, dentine height, pulpheight and pulp width which exhibit sexual dimorphism.Sexual dimorphism by evaluation of MCI has been studied inPakistan previously. Mughal et al determined gender in about 76%cases using MCI10. However, the purpose of our study was toaccess MCI in two different populations, to determine the accuracywith which the gender can be determined and to comparativelydetermine a possible MCI value that can be kept as standard forboth the populations.

MATERIALS AND METHODS:The study was conducted at Department of Forensic Medicine,Dow Medical College, Civil Hospital Karachi, Pakistan andDepartment of Dentistry, Queen Mary University, London, UK.This was a cross-sectional comparative study extending over aperiod of 1 year from January 1st, 2011 to December 31st, 2011.Out of a total of 89, 77 cases were enrolled in the study fromPakistan (39 males, 38 females) and 12 from UK (8 males and 4females).Data Collection: Data was collected using a divider. All themeasurements were intra-oral. The width of mandibular canineswas taken as the greatest mesiodistal width between the contactpoints of the teeth on either side of the jaw. The followingmeasurements were taken in all casts.1. The greatest mesiodistal width of the mandibular canine (both

on the right and left sides).2. The intercanine distance (i.e. the distance between the tips

of both canines in the lower jaw).The following parameters were determined on study casts in

males and females:1. Intercanine distance2. Right mandibular canine width3. Left mandibular canine width4. Mandibular canine indexMandibular canine Index (MCI) was then evaluated by the formula:MCI = Mesiodistal width of mandibular canine /Mandibularintercanine distanceThe standard value of the mandibular canine index is applied asa cut-off score to distinguish males and females. It is obtained bythe formula:Standard MCI = [(Mean male MCI - SD) + (Mean female MCI+SD)] / 2The MCI calculated in individual was related to standard MCIobtained by the above-mentioned formula.Analysis of Data: Statistical data was analyzed using StatisticalPackage of Social Sciences (SPSS) version 16. The frequency andpercentages were calculated for categorical variable that includedgender.The mean + SD was calculated for canine width, intercaninedistance and mandibular canine index. P-values were calculatedusing Pearson Chi Square Test.

RESULTS:Pakistan:The mean canine width among the 39 males was found to be0.7192 ± 0.06242 cm. While among 38 females, the mean caninewidth was found to be 0.6329 ± 0.06182 cm [p=0.000].The mean inter-canine width among the males was found to be2.4449 ± 0.23446 cm. However in females, it was found to be

2.9289 ± 0.47699 cm [p=0.000]. Thus, females were found tohave a greater mean inter-canine width than males.Furthermore, mean canine mandibular index was found be greaterin males i.e. 0.295 ± 0.020932 cm while in females, it was foundto be 0.2208 ± 0.03810 cm [p=0.000].Hence, the standard MCI in our Pakistani population was foundto be 0.266484 cm, which gets rounded off to 0.2665 cm. Withthe help of this standard MCI, we predicted gender correctly in94.87% males and 89.47% of females.United Kingdom: The standard MCI in our cases from UK wasfound to be 0.2705545 cm, which gets rounded off to 0.2706 cm.Keeping this MCI in mind, we correctly predicted the gender in100% males and 100% females.Comparative Analysis: The standard MCI after a comparativeanalysis of both the populations was concluded to be 0.26868 cm,which gets rounded off to 0.2687 cm. In accordance with thisstandard MCI, gender was correctly determined in 95.74% malesand 90.47% females.

DISCUSSION:Our study reported a very significant rate of sexual dimorphismin mandibular canines, about 90% in females and 96% in males.It is much more significant than the study conducted previouslyin Pakistan, reporting sexual dimorphism in only about 76%.Padmavati et al conducted a study in Vikarabad, India on agegroup 19-25 years where about 73.3% of the males and 80%



in relation to the specific demands of forensic practice. Int J Legal Med.2000;113(3):129-36.

2. Garvin HM, Passalacqua NV. Current practices by forensic anthropologistsin adult skeletal age estimation. J Forensic Sci. 2012 Mar;57(2):427-33.

3. Acharya AB, Mainali S. Are dental indexes useful in sex assessment?J Forensic Odontostomatol. 2008 Dec 1;26(2):53-9.

4. Kanchan-Talreja P, Acharya AB, Naikmasur VG. An assessment of theversatility of Kvaal’s method of adult dental age estimation in Indians.ArchOral Biol. 2012 Mar;57(3):277-84.

5. Fernandes MM, Tinoco RL, de Braganca DP, de Lima SH, FrancesquiniJunior L, Daruge Junior E. Age estimation by measurements ofdeveloping teeth: accuracy of Cameriere’s method on a Braziliansample. J Forensic Sci. 2011 Nov;56(6):1616-9.

6 . Rao NG, Rao NN, Pai ML, Kotian MS. Mandibular canine index-A clue for establishing sex identity. Forensic Sci Int. 1989;42(3):249-254.

7. Lund H, Mornstad H. Gender determination by odontometrics in aSwedish population. J Forensic Odontostomatol. 1999;17(2):30-4.

8. Karaman F. Use of diagonal teeth measurements in predicting genderin a Turkish population. J Forensic Sci. 2006;51(3):630-5.

9. Greene DL, Environmental Influences on Pleistocene Hominid DentalEvolution. 1970;20(5):276-279.University of California Press.

10. Mughal IA, Saqib AS, Manzur F. Mandibular Canine Index (MCI). TheProfessional Medical Journal. 2010;17(3):459-463.

11. Padmavati K, Momin FV, Ahmed SA, Ather SA. Mandibular CanineIndex- A tool for sex determination. J Indian Dent Assoc. 2011;5(1):18-20.

12. Acharya AB, Angadi PV, Prabhu S, Nagnur S. Validity of the mandibularcanine index (MCI) in sex prediction: Reassessment in an Indiansample. Forensic Sci Int. 2011:204(1-3):207.

13. Reddy VM, Saxena S, Bansal P. Mandibular canine index as a sexdeterminant: A study on the population of western Uttar Pradesh. JOral Maxillofac Pathol. 2008;12(2):56-59.

14. Yadav S, Nagabhushana D, Rao BB, Mamatha GP. Mandibular canineindex in establishing sex identity. Indian Journal of Dental Research.2002;13(3-4):143-6

15. Sperber G. The genetics of odontogenesis: implications in dentalanthropology and palaeo-odontology. Transactions of the Royal Societyof South Africa. 2006;61(2).

16. J.Michael Plavcan, Carel P. van Schaik, Interpreting hominid behavioron the basis of sexual dimorphism, Journal of Human Evolution.1997;32(4):345-374.

17. Kaushal S., Patnaik V.V.G., Agnihotri G. Mandibular Canines In SexDetermination. J Anat. Soc. India. 2003;52(2):119-124.

18. Sherfudhin H, Abdullah MA, Khan N. A cross-sectional study of caninedimorphism in establishing sex identity: comparison of two statisticalmethods. Journal of Oral Rehabilitation. 1996;23(9):627-631.

19. Muller M, Lupi-Pegurier L, Quatrehomme G, Bolla M. Odontometricalmethod useful in determining gender and dental alignment. ForensicScience International. 2001;121(3):194-197.

20. Acharya AB, Mainali S. Limitations of the mandibular canine index insex assessment. Journal of Forensic and Legal Medicine. 2009;16(2):67-69.

21. Vishwakarma N, Guha R. A study of sexual dimorphism in permanentmandibular canines and its implications in forensic investigations.NepalMed Coll J. 2011 Jun;13(2):96-9.

females were correctly detected using mandibular canine indices11.Acharya et al reported a low 51% accuracy rate of this methodin Karnataka, India12. A study from Uttar Pradesh, India carriedon 100 males and 100 females belonging to age group 17-25reported 70% efficiency of MCI in determining gender13, whilesimilar study conducted in Devangere, India detected 83% malesand 81% females14. Thus, our study has reported in relation themost accurate MCI values with significant results.Teeth measurements provide a useful adjunct in sex determinationin forensic odontology and paleontology. Because of their uniquestructure and composition, teeth are the last structures to degeneratepost-mortem. Thus, they can assist in forensic science to determinesex, age and race even years after death. Teeth develop from acomplex series of molecular interactions. Genes for the developmentof teeth are located on the 22 pair of autosomes and as well asthe sex chromosomes15. Development of permanent canines iscompleted in early adolescence. Canines are used in human beingto assist mastication and cut fibers in food product. Canines havethe ability to resist post-mortem which has made them valuablein identification of sex. Canines are marker of aggression, a morecharacteristic attribute in males. Thus, sexual dimorphism in caninesas seen among males and females and as mentioned from abovestudies is not merely by chance but it is because of the functionaldifferences between both genders16. Kumar et al verified thatinter-canine distance and mandibular canine index are usefulmeasurements in distinguishing between sexes. Kaushal et al conducteda study among 60 college students in Patiala and mentioned thatdifferences may also exist between corresponding canines. Hereported that left mandibular canine exhibited greater sexualdimorphism then the right mandibular canine17. He also mentionedthat gender is most likely to be male when the width of the canineis greater than 7mm17. Furthermore, Sherfudhin et al also indicatedsignificant dimorphism in maxillary canine as well18.Regardless of the above results provided by the above mentionedstudies some limitations also occur. Muller et al conducted astudy in which tooth occlusion was taken into consideration. Theresults were compared with standard MCI19. Acharya et al alsoexplained the reason which can diminish the ability of MCI in sexdetermination is attributed to it being a ratio (MD dimension ofcanine and inter-canine arch width) rather than an absolutemeasurement20. In our study, both these parameters were measuredand compared in males and females and the differences were foundto be statistically significant.Despite the above mentioned limitations, MCI is still a simple,swift and inexpensive method for determination of gender and hasprovided investigators with significant results21. Thus, allowing itto be used worldwide in forensic medicine.

REFERENCES:1. S. Ritz-Timme, C. Cattaneo, M. J. Collins, E. R. Waite, H. W. Schütz,

H.-J. Kaatsch, H. I. M. Borrman. Age estimation: The state of the art

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Gender Determination