jiafm, 2010-32(2) april-june. - forensic medicine

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ISSN 0971-0973 J Indian Acad Forensic Med, 32(2)The combined bone fusion score was foundto be 3.514 with a standard error of 1.284, and a p > It I value of 0.01. It was found to be statisticallysignificant, and was used for the equation forestimation of age in the prediction model.The oral orthopantomograms (OPGs) wereexamined for changes in the mandible, namely theperpendicular distance of the mental foramen fromlower border of body of the mandible (D1), the leastperpendicular distance of the mandibular canals fromthe tangents drawn along the lower borders of thebody of the mandible (D2), and the angle between thetangents drawn along the posterior border of the ramiof the mandible and the lower borders of the body ofthe mandible.The mean values of each measurement oneach side of each group (control and study) were thencalculated, and are shown in Table 5, above.Linear Regression:Using the relevant data of cases, viz., thenine independent variables of Combined Hair Score,Combined Skin Score, Combined Bone Fusion Score,Mandible Right D1, Mandible Right D2, MandibleRight Angle, Mandible Left D1, Mandible Left D2,and Mandible Left Angle were linearly regressedagainst the known dependent variable „Age‟ todevelop a prediction Model for Age estimation.AM (The American Institute for Research and JohnCohen) Statistical Software Beta Version – 0.06.02was used for the execution of the regressioncommand.The 32 cases of the control group, whoseages were known, were used for the Regression(Prediction Model).Adjusted Wald TestF(9,23)=46.2231P(F> f) = 1.2913e-012Extremely SignificantDependent Variable: AgeR=0.936R-Square = 0.877Ratio of the mean square, i.e., the F Statistic,was very high, and was extremely significant, as canbe seen from the p value (< 10 -11 ) in the Wald test.There was very high correlation between thepredicted values and the observed values of thedependent variable (Age) given by the regressionmodel (Correlation Coefficient = 0.936)Around 88% of the variation in the dependentvariable (Age) can be explained by the independentvariables.This showed very high fitness of this predictionmodel (88%).The following variables proved to be significantlyassociated with, and more important in the estimationof age:1. Combined Skin Score2. Combined Bone Fusion Score3. Mandible Right D24. Mandible Right Angle5. Mandible Left AngleThe standardized estimates clearly demonstrated thatthe most important of these were the Mandible RightAngle and the Combined Skin Score.The model thus yielded the following regressionequation:Age=2.562 (combined skin score)+3.514 (combined bone fusion score)+8.687 (mandible right D2)+0.436 (mandible right angle)-0.263 (mandible left angle)-+8.442 (constant)As the model used the data from subjects between25 to 45 years of age, this equation can be used forthis age group, and holds true with 88% accuracy.Using this regression equation, the age of the 32subjects in the study group was estimated as shown inTable 6.Discussion:Hair on the head tends to become grayusually after 40 years of age and silvery white inadvanced old age. [1, 2] Graying of the hair wasfound to be of no statistical significance for theestimation of age. This was due to the fact that thepatterns of graying of hair are very unreliable. Manyfactors have been held responsible for this, amongthem nutrition, shock, [3] cosmetics and black or redcoloring for concealment of age, and artificialcoloring according to the dictates of current fashion(either darkened by using henna, phenylenedioamine,metallic salts of lead, bismuth or silver, or bleachingwith chlorine, hydrogen peroxide, dilute nitric acid ornitrohydrochloric acid). Colour changes due tooccupation have also been observed, e.g., a greenishhue in ebony turners and copper smelters, and abluish tinge in indigo workers. [1] A plethora ofhereditary factors (autosomal dominant conditionssuch as progeria, Werner‟s syndrome, myotonicdystrophy, Book‟s syndrome, Fisch‟s syndrome,Rothmund-Thomson syndrome, Waardenburgsyndrome, ataxia telangiectasia, Seckel‟s syndrome,cri-du-chat syndrome, multiple lentigines syndrome),autoimmune disorders like pernicious anaemia,hypothyroidism, hyperthyroidism, sympatheticconditions (facial hemiatrophy), infections (e.g.,HIV), certain metabolic defects like oculocutaneousalbinism or albinoidism, Hemansky-Pudlacksyndrome, Cross-McCusick-Breen syndrome, Tietz116
J Indian Acad Forensic Med, 32(2) ISSN 0971-0973syndrome (all of them are generally due to defectivemelanin production) and last, but not the least, drugssuch as chloroquine, triparanol, flurobutyrophenone,mephenesin and dixyrazine, all play a greater orlesser role in the early or delayed graying of hair. [4]The statistically significant variables, asalready mentioned in the results, are skin changes,fusion of the components of sternum, position of themandibular canal and the angle of the mandible onthe right side, and the left angle of the mandible. Ofthese, the skin changes are of least reliable, becauseof the variety of factors affecting it, viz. heredity(aging genes, cellular senescence, telomereshortening, longevity genes, and nonenzymaticglycosylation), nutrition, oxidative stress, amino acidracemisation, exposure to sunlight, (Photoageing --one of the most crucial factors in the Indiansubcontinent), smoking, treatments likephotoprotection, trans-retinoic acid, alpha-hydroxyacid, antioxidants or Hormone therapy, caloricrestriction, application of cosmetics and, morerecently, injection of medicines into the skin andmuscles (Botox / Dysport / Myobloc -- the Botulinumtoxin A and Botulinum toxin B preparations) [5] as aremedy for of wrinkles of the skin.The manubrio-sternal joint, which liesbetween the manubrium and sterna body is usually asymphysis, the bony surfaces are covered by hyalinecartilage and are connected by a fibrocartilage whichmay ossify in the aged. [6, 7, 8] The fusion of thecomponents of the sternum, [6, 9] as visualized inright lateral views of X-rays of the chest, were foundto be useful enough for the estimation of age in thisparticular age group.The first practical method for estimation ofage at death of individuals from their teeth waspresented by Gustafson. [10] The mandibular canaland mental foramen are standard anatomicallandmarks. [7] Changes in the mandible, [2, 6, 8, 11]as seen in oral orthopantomogram, particularly on theright side, were determined to be of greater value forage estimation than those on the left side. The reasonsfor such a difference are thought to be a missing tooth/ missing teeth on either side, artificial dentures oneither side, chewing habits, malocclusion of a tooth /teeth, non-eruption of a tooth / teeth, and thehandedness of the person. (The handedness of theperson is related to the dominance of the cerebralhemisphere. Therefore, in a right-handed person, as isthe case with majority of the population, [12, 13] useof the dominant hand, e.g., the right hand forbrushing the teeth will exert more pressure on theright side of the mandible while brushing the teeththan a left-handed person, who will induce more agerelatedchanges on the left side than the right.Conclusion:The observations and results of the studyconfirmed the presumption made before it wascommenced that subjective assessment of graying ofhair was of little or no help in the estimation of agebecause of the host of factors that were involved inwhen it commenced or why it never appeared at all.This was emphasised by statistical analysis of aCombined Hair Score (CHS) that had beendeveloped.Although a roughly equivalent number offactors played a role in changes in the skin, wrinklingat the three locations mentioned above proved moresignificant in that regard when converted into aCombined Skin Score (CSS).Of all the parameters studied, a review ofliterature suggested that the least criterion affected byexternal and internal factors was fusion of themanubrium and xiphoid process with the body of thesternum, however uncertain the ages at which thesephenomena occur might be. The degree of theirreliability in the estimation of age was borne out bystatistical analysis of the data, which yielded a highsignificance and highest coefficient of a CombinedBone Fusion Score (CBFS) in the equation for theassessment of age in the later years.Among the age changes in the mandible, theright and left angles (MRA & MLA) and the leastperpendicular distance between the mandibular canalon the right side and a tangent drawn along the lowerborder of the body of the mandible (MRD2) turnedout to be the most reliable parameters in theassessment of age in the later years, and weretherefore incorporated into the equation developedfor that purpose.Using statistical analysis of the data, linearregressions graphs were prepared on a speciallydeveloped software program by plotting fivesignificant variables (CSS, CBFS, MRD2, MRA andMLA) against the dependent variable of age Thefollowing equation for estimation of age between theages of 25 and 45 years was derived from thesegraphs:Age = 2.562(CSS) + 3.514(CBFS)+ 8.687(MRD2) + 0.436(MRA)- 0.263(MLA) + 8.442From a statistical standpoint, the fitness ofthe formula (i.e., its accuracy) was very high (88%).Using this formula, the ages of the 32 subjects in thestudy group were predicted, and were found to tallyalmost exactly with the ages as claimed by 22 (69%)of them.In conclusion, it may be said that thisparticular study has succeeded in most instances inpredicting the ages of the study group, and in arrivingat a formula for age estimation between the ages of25 and 45 years without using any invasive, costly,117
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