Mandible

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Mandible

  1. 1. CAPT RISHI POKHRELCOL RAJAN BHATNAGARCOL SUSHIL KUMAR
  2. 2. INTRODUCTION Determination of sex from skeletal remains – initial step in determination of identity Human mandible - among the strongest bones - significant sexual dimorphism Multivariate Discriminant Functional Analysis (MDFA) – best among metric methods. Population: Marathwada region of Maharashtra.
  3. 3. AIMS & OBJECTIVES To test sexual dimorphism in mandibles of population under study. To identify parameters of mandible that show maximum sexual dimorphism To determine population specific cut off point and constants for MDFA. To test the accuracy of MDFA.
  4. 4. MATERIALS & METHODS Cross sectional, observational study Adult mandibles of known sex from Anatomy department, GMC, Aurangabad. Sample size : 103  Males: 77 Female, 26  Females : 26 Male, 7 Exclusion criteria 7  Incomplete  Gross asymmetry  Extreme of ages
  5. 5. MATERIALS USED
  6. 6. MATERIALS USED
  7. 7. PARAMETERS USEDParameter (Midline) Abbn. Parameter (Bilateral) Abbn.Symphyseal height ID GN Height of mandibular body HTBicondylar breadth CDL CDL Mandibular thickness at mental MB foramenBigonial breadth GO GO Minimum ramus breadth MnRbMandibular length ML Maximum ramus breadth MxRBIntermolar distance IMD Mandibular or gonial angle AIntercanine distance ICDArch perimeter AP Units mm, degree, cms
  8. 8. STATISTICAL ANALYSIS MDFA (multivariate discriminant function analysis) Stepwise MDFA Analysis : SPSS 19
  9. 9. OBSERVATIONS & RESULTS
  10. 10. MEAN VALUES140120 MALES100 80 FEMALES 60 40 20 0 ID GN HT LT MB LT GO GO CDL CDL Mn RB Mx RB Mx RH ML A IMD ICD AP
  11. 11. DESCRIPTIVE STATISTICSVariable TOTAL (N = 103) MALE (N = 77) FEMALE (N = 26) P value MEAN SD MEAN SD MEAN SDID GN 27.06 4.27 27.55 4.25 25.62 4.07 0.0456HT 26.48 3.48 26.77 3.46 25.60 3.43 0.138MB 10.60 1.33 10.74 1.39 10.17 1.05 0.059GO GO 100.20 9.86 101.90 8.99 95.15 10.74 0.002CDL CDL 115.63 9.40 116.86 7.76 111.96 12.6 0.021Mn RB 33.61 5.69 35.35 5.38 28.47 2.74 <0.001Mx RB 43.03 6.27 44.83 5.85 37.69 4.09 <0.001Mx RH 63.17 7.25 64.13 6.64 60.32 8.32 0.020ML 66.62 7.00 68.22 6.31 61.89 6.91 <0.001A 118.79 6.87 117.84 6.67 121.58 6.81 0.016IMD 36.55 5.87 36.80 5.88 35.80 5.90 0.456ICD 23.10 7.01 23.91 7.26 20.68 5.65 0.042AP 7.011 1.00 7.08 1.06 6.80 0.81 0.228
  12. 12. Parameter b STEP 1: MDFA ID GN -0.037 Multivariate discriminant function HT 0.076 f (x) = b0 + b1x1 + b2x2 + b3x3 + --------- + b13x13. MB 0.267 GO GO -0.050 Where, f (x) : MDFA score CDL CDL 0.041 b0 : constant (-7.704) Mn RB -0.185 Mx RB -0109 b1 to b1 : raw coefficients Mx RH 0.053 x1 to x13 : variables values ML -0.015 f(x) at group centroid for males = - 0. 556 A 0.101 IMD 0.053 f(x) value at group centroids for females = 1.648 ICD 0.033 Demarcation point = 1.09 AP -0.301
  13. 13. STEP 2: STEPWISE MDFA A combination of MnRB and A was found to be best among all. The function f (y) = b0 + b1 (MnRB) + b2 (A) b0 = 3.755 b1 = 0.202 b2 = - 0.089 f(x) at group centroid for males = 0.435 f(x) value at group centroids for females = -1.288 Demarcation point = - 0.9628
  14. 14. RESULTS MDFA S-MDFA 100 Percentage 80 60 40 20 0 Male Female OverallMETHOD Male Female Male % Female % Overall %MDFA 72/77 21/26 93.5 80.8 90.3S- MDFA 76/77 12/26 98.7 46.2 85.4
  15. 15. FUNCTION FOR MDFA f(x) = (- 0.704) + (-0.037) ID GN + (0.076) HT + MB (0.267) +GO GO (-0.050) + CDL CDL (0.041) + MnRB (-0.185) + MxRB( -0109) + MxRH (0.053)+ ML (-0.015) + A (0.101) + IMD (0.053) + ICD (0.033) + AP (-0.301) f(x) > 1.09, the mandible belongs to female f(x) < 1.09, the mandible belongs to male Accuracy : 90.3%
  16. 16. FUNCTION FOR S - MDFA f(y) = 3.744 + (0.202) MnRB + (-0.089) A If, f(y) > - 0.9628 the mandible belongs to male and if f(y) < - 0.9628, the mandible belongs to female Accuracy: 85.4%
  17. 17. DISCUSSION Author (s) with population No of Parameters Accuracy % used(Hanihara, 1959), Japan 4 88.6(Giles, 1964), USA 3–8 82.0 – 88.0(Potsch-Schneider et al., 1985), Germany 17 71.6 - 81.7(Steyn & Iscan, 1998), South Africa 5 81.5(Barthélémy et al., 1999), France 2-7 87.3(Muñoz et al., 2001), Spain 1 - 14 78.3 - 88.7(Vodanović et al., 2006), Croatia 1-9 74.12 – 92.06(Simona et al., 2007), Romania 5-7 86.0(Saini et al., 2011), Varanasi, India 1-5 60.3 - 80.2Current study, 2012, Maharashtra, 2 - 13 85.4 – 90.3India
  18. 18. Saini et al, 2011, Indian Population (Varanasi) Sample size : Total 116, Male 92, Female 24 Functions and Variables Avg. Acc. %Max. ramus br. + min. Ramus. br. + condylar ht. + projective ht. + 80.2coronoid ht.Max. ramus br. + min. ramus br. + coronoid ht. 80.2Condylar ht + projective ht + coronoid ht. 76.7Coronoid ht. 74.1Condylar ht. 72.4Projective ht. 68.1Max ramus br. 62.1Min ramus br. 60.3 Our study Maximum 90.3% Minimum 85.4%
  19. 19. CONCLUSIONS Mandibles of population under study show sexual dimorphism. MnRB and A show maximum sexual dimorphism. Population specific coefficients, constants and demarcation points for MDFA are derived.Accuracy of sexing is comparable to other populations.

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