AGE ESTIMATION IN FORENSICS

Age estimation in forensics for dental students

1. AGE ESTIMATION IN FORENSICS PRESENTED BY N.NARMATHA I YEAR PG

2. INTRODUCTION: Forensic odontology is the proper handling, examination and evaluation of dental evidence, which will be then presented in the interest of justice Evidence from teeth is the age and identification of the person to whom the teeth belong by using dental records or antemortem photographs.

3. DENTAL AGE ESTIMATION: Final step in the triad of dental profiling Age estimation is an important sub speciality of forensic sceinces Applicable from infancy to late adolescence and also for adults. Methods : Morphologic,radiographic,histological and biochemical methods to examine age dependant changes in teeth Three phases Prenatal, neonatal ,early post natal period Children and adolescents A dults

4. AGE ESTIMATION IN PRENATAL, NEONATAL ,EARLY POST NATAL PERIOD: Primary teeth begin to calcify at approximately 12-14 weeks inutero Enamel formation of deciduous teeth is complete by first year. First permanent molar- commences calcification around the time of birth . Aka and coworkers – measure the developing calcified teeth correlating to age. Laly’s and colleagues- use CT scans Stack – dry weight of mineralized tooth cusps of deciduous central incisor, lateral incisor and first molar

5. Six months intrauterine life – combined weight of teeth in child is 60mg, 0.5 mg in newborn 1.8 gm at six months after birth. Neonatal line: Indicator of live birth Ciapparreli – neonatal line may take upto 3 weeks after birth to form – estimating age in this group have legal implications

6. AGE ESTIMATION IN CHILDREN AND ADOLESCENTS Two events measure dental age Tooth emergence tooth calcification Nystrom and colleagues – study of tooth emergence as convenient clinical method Limited to deciduous teeth Commences approximately at six months after birth and completing by about 2 ½ years .

7. Radiographs assess calcification of permanent dentition – better alternative Since calcification of teeth can be observed on R/G for a period of several years. Not altered by local factors Study of tooth calcification allows as to assess age at 2 ½ - 6 years > 12 years Dental calcification- better indicator of age in first two decades of life.

8. SCHOUR AND MASSLER’S METHOD First attempt at scientific dental age estimation. 20 chronologic stages of tooth development from 5 months IU until 21 years of age Chart is based on histologic sections and permit direct comparisons with radiographs.

9. DEMIRJIAN’S METHOD: Assess the mandibular left side teeth. Most widely used technique – assessing age in children and adolescents. ADVANTAGES: Detailed descriptions and radiographic illustrations of tooth developmental stages Relative simplicity Chaillet and demirjan – modified and included third molar – provided separate maturity score for each sex. Calcification of teeth was divided into 10 stages and numbered ‘0’ to ‘9’

10. Maturity score: Stage 0 – calcification is yet to begin Stage 5 – crown completion Stage 9 – completion of tooth calcification Acharya – formula for Indians Males: 27.43521-(0.0097 x S2) + (0.000089 x S 3) Females : 23.7288 –(0.0088 x S2) + (0.000085 x S3 ) Average absolute error is ± 1.43 years of actual age Produce dental age ,on average is closer to the real age by about six months – assess age in child or adolescent.

11. VALUE OF THIRD MOLAR IN AGE ESTIMATION: Valuable indicator of age in 16-22 year old age Determine whether an individual is a juvenile (< 18 yrs ) or an adult(>18 yrs ) In I ndia – 18 years is the threshold age Acharya – applied Demirjian’s grading to third molar – correctly predicted juvenile/adult status(73.2 %)

12. AGE ESTIMATION IN ADULTS: Gustafson’s method: D escribed age changes in the dental tissues and noted six changes related to age. They are: Attrition of the incisal or occlusal surfaces due to mastication (A) Periodontitis (P) Secondary dentin (S) Cementum apposition (C) Root resorption (R) Transparency of the root (T )

13. Gustafson suggested the last two changes Each sign was ranked and allotted 0, 1, 2, 3 points. Formula: An+ Pn + Sn + Cn + Rn + Tn = points The exact equation calculated was: y = 11.43 + 4.56x ( y = age and x = points) Error was ±3.6 years. Disadvantage : Cannot be used in living person

14. Pillai and Bhaskar applied this method on Indians – error ± 8 years JOHANSON METHOD ( 1971) Widely recommended Age changes were differentiated into seven different stages (A0-A3) and evaluated for the same six criteria Root transparency - more clear when the thickness of the ground section of the tooth was 0.25 mm Age = 11.02 + (5.14 × A) + (2.3 × S) + (4.14 × P) + (3.71 × C) + (5.57 × R) + (8.98 × T)

15. DENTIN TRANSLUCENCY: Diameter of dentinal tubules as a result of intra tubular calcification Differences in refractive indices between intra tubular organic and extra tubular inorganic material is equalized – translucency of affected dentin. BANG AND RAMM – measured length of translucency Predictable increase in root translucency as age increases.

16. Acharya modified bang and ramm’s method – common to all single rooted teeth Formula I – 35.5619 + (3.4828 x T) (translucency > 9mm ) Formula II – 29.9074 + ( 7.4507x T ) + (M -0.4369 X T 2) (translucency < 9mm ) Error ± 8.3 years Measured on either intact extracted teeth or ground sections of teeth. Convenient to postmortem age estimation Disadvantages: Junction between translucent and non translucent zones - irregular

17. AGE ESTIMATION FROM INCREMENTAL LINES OF CEMENTUM: ( Kagerer and grape) Makes use of mineralized,unstained cross sections of teeth Accuracy : 2 – 3 years of actual age . Hypomineralizedd bands – give an indication of events such as pregnancies , skeletal trauma , renal disorders

18. Camerire & associates used non destructive radiographic technique.

19. PULP-TO-TOOTH RATIO METHOD BY KVAAL Pulp-tooth ratio is calculated for six mandibular and maxillary teeth Maxillary central and lateral incisors, second premolars Mandibular lateral incisor,canine and first premolar. Age = 129.8 – (316.4 × m) (6.8 × [W-L])

20. THE CORONAL PULP CAVITY INDEX: Calculates the correlation between the reduction of the coronal pulp cavity and the chronological age. Mandibular premolars and molars were considered Panoramic radiography is used The tooth-coronal index (TCI) is computed for each tooth and regressed on the real age of the sample using the formula. TCI = CPCH X 100/CL

21. AMINO ACID RACEMIZATION: Helfman and bada first suggested a relationship between age and extent of aspartic acid racemization in dentin. L- aspartic acid D aspartic acid Constant change at different ages – used for age estimation. Measured at brain cells , crystalline lens, bones and teeth Racemization rate – higher in root dentin – valuable tissue for using this method .

22. AGE ESTIMATION FROM 14 C LEVELS: Amount of carbon isotope in enamel and compares it to recent atmospheric levels of 14 C

23. NOLLA’S METHOD (1960) Evaluated mineralization of permanent dentition in 10 stages. Every tooth is assigned a reading - total is made of the maxillary and mandibular teeth - compared with the table given by Nolla .

24. MOOREES, FANNING AND HUNT METHOD (1963) Dental development was studied in the 14 stages of mineralization for developing single and multirooted . Permanent teeth and the mean age for the corresponding stage was determined

25. CONCLUSION Determination of dental age is done by reference to the ever-growing human deciduous and permanent dentitions. The importance of age estimation includes an assessment of minor/major status in individuals without legal documents, Demirjian method, the widely used method with appropriate modifications shall be a reliable method.

26. References 1.Shafer's Textbook of Oral Pathology - Arya Rajendran , B Sivapathasundharam - Google Books_files 2. Smith T, Brownlees L. Age Assessment Practices: A Literature Review & Annotated Bibliography. New York: United Nations Children’s Fund (UNICEF); 2011. 3. McKenna CJ, James H, Taylor JA, Townsend GC. Tooth development standards for South Australia. Aust Dent J 2002;47:223-7. 4. Al- Emran S. Dental age assessment of 8.5 to 17 Year-old Saudi children using Demirjian’s method. J Contemp Dent Pract 2008 1;9:64-71. 5. Stavrianos C, Mastagas D, Stavrianou I, Karaiskou O. Dental age estimation of adults: A review of methods and principles. Res J Med Sci 2008;2:258-68