Forensic Odontology.pptx for BDS students

Age estimation

1. G O O D M O R N I N G

2. Forensic odontology

3. Introduction History Need Identification 1. Comparative- Disaster site 2. Dental Profiling- Ethnicity Tooth Morphology & Sexing Dental age estimation methods Crime inv- bite mark & lip print analysis Conclusion References

4. Forensic is derived from the Latin word forum, which means public square in an ancient Rome city used for judicial & other business

5. Latin word forum = public square

6. FDI -'that branch of dentistry which, in the interest of justice, deals with the proper handling and examination of dental evidence, and with the proper evaluation and presentation of dental findings'. It primarily deals with identification, based on recognition of unique features present in an individual's dental structures. It relies on sound knowledge of the teeth and jaws, possessed by dentists and incorporates dental anatomy, histology, radiography, pathology, dental materials, and developmental anomalies.

7. Bible- bite mark by Adam The earliest identification by dental means - 66 AD, Roman queen 1193 Maharaja of Conouj – Jai Chandra Rathore was id in the warfield by enemy troop by his golden crown 1775 Battle of Bunkers hill - Paul Revere id Joseph’s body by his amalgam bridge. HISTORY…

8. T he most high profile case of dental identification - Adolph Hitler Elaborate dental records including radiographs and spare crowns

9. Dentition was an imp lead in the id of the remains of various leaders who were killed like Zia Ul Haq (1988), former Paki president & Rajeev Gandhi , former Indian prime minister(1991).

10. Nothing has brought the FD to the emerging front like the sep 11 attack on WTC

11. FORENSIC ODONTOLOGISTS DELVE INTO : Identifying unknown human remains through dental records, and assisting at the location of a mass disaster . Eliciting the ethnicity and assisting in building up a picture of lifestyle and diet of skeletal remains at archaeological sites . Determining the gender of unidentified individuals . Age estimation of both the living and the deceased . Recognition and analysis of bite marks found on victims of attacks and in other substances such as foodstuffs . Presenting evidence in court as an expert witness .

12. Identification Establishment of a person's individuality. He who has gone, so we but cherish his memory, abides with us, more potent, nay, more present than the living man. ~Antoine de saint Proper identification of the dead - legal and humanitarian reasons.

13. Most parts of the body undergo changes as the individual ages & are replaced/recycled depending on tissue involved. The teeth are unique in that once physiological/growth information is built into them they may remain stable for thousands of years even after death. T eeth - strongest structures+ most materials used by the dentist for restoring teeth are resistant to post-mortem decomposition. Traditional methods of identification have included visually recognizing the body, fingerprints and personal property such as clothing, jewellery , etc.

14. When facial forms & finger prints fail-dentition enters the scene Identifying a body that is burned/ traumatized or decomposed & skeletonized remains - can be a very traumatic experience for relatives and friends

15. Basis for Dental Identification T heory that human dentition is never the same in any two individuals. The morphology and arrangement of teeth vary from person to person. Although teeth are relatively resistant to environmental insults after death, during life they are susceptible to physiological and pathological changes. R estorations , teeth that cannot be restored may have been extracted .

16. combinations 16 missing teeth - 600 million. Sixteen filled teeth produce a similar combination. Four missing and four filled teeth in a mouth combined can produce more than 700 million combinations.

17. Now, every tooth has five surfaces. If, instead of considering the whole tooth, the surfaces were taken individually, the variations produced would be astronomic. In fact, there are 1.8 X 10 19 possible combinations of 32 teeth being intact, decayed, missing or filled.

18. DENTAL IDENTIFICATION PROCEDURES 1. Comparative identification: attempts conclusive identification by comparing the dead individual's teeth with presumed dental records of the individual. 2. Reconstructive identification or Dental Profiling: attempts to elicit the ethnicity or 'race‘, gender, age, and occupation of the dead individual. This is undertaken when virtually no clue exists about the identity of the deceased.

19. Comparative dental identification C onventional method of post-mortem dental identification Four steps : Oral autopsy Obtaining dental records Comparing post and ante-mortem dental data Writing a report and drawing conclusions.

20. I. Oral autopsy Autopsy (necropsy or post-mortem) involves examination of the deceased, usually with dissection to expose the organs, to determine the cause of death. FD is invited to assist in a particular case investigated by the police/forensic pathologist. Dentist is rarely the first expert to be called… CDI

21. Protective clothing Lip retractors, tongue blade, rubber mouth props, mouth gag-forceps/screw ty . Dental instruments-mouth mirrors, tweezers, probes, excavators, plastic instruments, surgical knives, scissors, dental X n forceps+ elevators, swabs & cotton pellets. EQUIPMENT & EXAMINATION

22. Impression materials. Photography : police photographer/professional. Centimeter scale is included within the frame of the photograph + tracings & labelled sketches of imp features on transparent overlays. CDI

23. EXAMINATION OF THE BODY Same sequence as a living person is examined. EO + IO followed by radiographs & other techniques. The whole body exam - bite marks Impression of the bite mark -silicone rubber is injected on to the area & this flexible impression has to be backed with strips of Plaster of Paris for rigidity. CDI

24. IO Examination Essential part of the post-mortem procedure. The forensic dentist should have adequate knowledge about common post-mortem findings such as rigor mortis, livor mortis, decomposition, & post-mortem artifacts. CDI

25. Rigor mortis may render the jaws rigid and the use of mouth-gags, or intraoral myotomy is essential for jaw separation. CDI Since teeth may be brittle in burned cases, they need to be enforced with cyanoacrylate cement, polyvinyl acetate, or clear acrylic spray paint prior to examination. Access for radiography in incinerated bodies can be obtained by removing the tongue and contents of the floor of the mouth in a 'tunneling' fashion from beneath the chin.

26. Every surface should be cleansed before examination Debris, blood, soil- toothbrush + soapy water Distribution, color & type of stains on teeth-tobacco, beverages, medicaments Periodontal condition, gingival attachment - Oral hygiene CDI

27. Soft Tissue to be examined for any trauma, pigmentations, tattoos CDI

28. Mucosal disease, Palate-smoking & Drug induced soft tissue changes CDI

29. TOOTH STATUS Occlusion - Malocclusion Deciduous/permanent teeth the status of each tooth (whether intact, carious, restored or missing) should be carefully noted. Unerupted teeth Dev missing teeth CDI

30. The absence of a tooth in an unidentified body when compared with the ante-mortem dental records does not rule out an id. It is necessary to be able to determine if it was lost before /after death . If the margins of the empty tooth socket are sharp & unresorbed , the tooth was probably lost after death . Resorption & remodeling of the socket margins would indicate that the tooth was lost before death.

31. Diastema Supernumerary teeth Extra cusp Carabelli Fused/geminated teeth Macrodontia Hereditary condition : AI, DI unusual wear & trauma Occupational habits Tooth Mobility+fracture –assault/injury Non-vitality CDI

32. Tooth restorations Amalgam Tooth col restoration Disclosing solution- boundaries of composite restoration Porcelain/acrylic crowns- margins Gold crown Bridge RCT CDI

33. Cases when tooth is broken-part of restoration/even the lining cement present will indicate a previous restoration.

34. Fire - metal act diff, mercury in amalgam may vaporize. Teeth incinerated at 600 o c-chalky white, extremely friable. Piece of amalgam still visible.

35. 100 c 200 c 400 c 800 c

36. The Palatal Rugae & Dentures I n identifying edentulous individuals. Rugae pattern, like teeth, are considered unique to an individual. They do not change shape with age and reappear after trauma or surgical procedures. CDI The rugae pattern on the deceased's maxilla or maxillary denture may be compared to old dentures that may be recovered from the decedent's residence, or plaster models that may be available with the treating dentist. Palatal rugae are well protected by the lips, cheek, tongue, buccal pad of fat, and teeth in incidents of fire and high-impact trauma.

37. Some dentures will have the patients name written or embossed on. Some dentures will show signs of having been repaired The dentist can id if its his work CDI

38. All findings rec on chart-assistant CDI

39. RADIOGRAPHY Skeletonized remains provide the easiest access for dental examination Skull & mandible can be readily transported - portable machine in the mortuary is inadequate Decomposed & unpleasant nature of the specimens requiring id- cover the instruments in plastic sheeting CDI

40. Method to take an IOPA R/G of Md teeth

41. POST-MORTEM PROCEDURES After rigor has set in + decomposition-diff to open jaws either manually/using lever type of mouth gag. Forcible attempts to gain access-damage to teeth/restoration Better to remove the jaws. Permission obtained from the pathologist & from the coroner- Removal of soft/hard tissue for further study Attendance of a defense expert CDI

42. Ant tooth restorations - confirm by R/G Recheck the dental findings after the jaws are removed Add info from R/G or sp studies such as microscopy shd also be incorporated at this stage. CDI

43. All the information pertaining must be entered onto the standard ‘Interpol post-mortem’ form, which is color-coded in pink. CDI

44. II. Obtaining Dental Records D ental records may be obtained from the treating dentist, specialist or hospital records. Whenever possible, the original record should be examined. Such records may be in the form of dental charts, radiographs, casts or photographs. It is likely that multiple dentists might have treated an individual. CDI

45. Hence, the contents of all available dental records should be transcribed onto the standard 'Interpol ante mortem form', which is color-coded in yellow . CDI

46. III. Comparing Post- and Ante-mortem Dental Data Once the post-mortem evidence and dental records are available, the data can be compared. Better- an individual with multiple dental treatment and unusual features than someone with no extraordinary dental characteristics. CDI

47. IV. Writing a Report and Drawing Conclusions One needs to remember that any attempt at establishing identity is addressed to the legal authorities. Therefore, a detailed report and factual conclusion, based on the comparison, must be clearly stated. The quality and quantity of information required for establishing dental identification may not have been established. CDI

48. For example, the post-mortem data may reveal a 'filling' on the right upper first molar, but the dental records show the same tooth as 'intact’. This difference, however, may be explained on the basis that the filling might have been done on a date after the available dental records, but for which no records are available. CDI

49. CONFIRMS IDENTIFICATION This indicates that the ante- and post-mortem data match each other. The identity is proven 'beyond reasonable doubt'. It usually includes radiographic support. PROBABLE IDENTIFICATION The data is consistent but a lack of quality ante­and /or post-mortem information- means one cannot confirm identity. There is a high level of agreement between the two sets of data but, usually, with no radiographic support . POSSIBLE IDENTIFICATION Explainable differences exist between the ante­and post-mortem data. CDI

50. The data contains unexplainable differences that comprehensively indicate a mismatch . The available ante- or post-mortem information is minimal or insufficient. For e.g. if the post-mortem data shows an 'intact' right upper first molar, whereas the same tooth is 'filled' in the dental records, this would probably mean a mismatch. CDI EXCLUDES IDENTIFICATION

51. IDENTIFICATION IN DISASTERS Disasters refer to natural, accidental, or man made events, such as earthquakes, floods, airplane crashes, and terrorist attacks, that result in multiple human fatalities.

52. Such events require identification of the post-mortem remains due to severe mutilation. The process of dental identification involves comparing hundreds, sometimes thousands, of ante- and post-mortem data

53. Human remains in such events may be highly fragmented, incinerated or commingled, i.e. parts of two bodies may be mixed. First aid/hospital ***

54. 50 % of id in disasters are by dental means. Representation on the dental section should be as broad as possible, and inclusion of different specialists and dental auxiliaries can be useful. Each team member - familiar with procedures to be followed in a disaster situation. Information about team activation, the tasks to be performed, standardized charting methods, etc. should be known in advance. Tasks may range from taking radiographs to performing clerical duties. Forensic dentists are usually part of a team of identification specialists that include anthropologists, and fingerprint experts, radiologists, pathologist etc.,

55. The Interpol's disaster victim identification guide suggest the division of the dental section into three subsections- post­mortem unit, ante-mortem unit, and dental comparison and identification unit.

56. Post-mortem Unit A sketch should be made of the scene. The location at which a body is recovered is noted and preliminary examination of the mouth is made to evaluate the oral condition. The definitive dental examination, however, is best performed at the temporary mortuary set up for post-mortem examination. dental examination is usually done after most other procedures such as photography, fingerprinting, and medical autopsy.

57. A portable dental radiography apparatus should be installed at a convenient area within the temporary mortuary. Teeth and jaw specimens may be removed from a body for the convenience of examination - labeled to prevent a 'mix-up'. Refrigerated trailer trucks

58. Ante-mortem Unit difficult. The members need to collect as much information as possible in the shortest period of time. This begins with locating the dental records of the victims, which requires an extensive network of communication with the police, dentists, and relatives of the victim.

59. The dentist is requested to provide the written dental records, radiographs, and study models to the ante-mortem unit. Information - transferred onto the standard Interpol ante-mortem form.

60. DRAWBACKS: The use of different types of tooth numbering system and nonstandardized abbreviations While the FDI system is preferred, other numbering systems such as Zsigmondy Palmer, ADA, are still employed in different countries. The use of abbreviations for recording dental treatment is common worldwide and varies from one dentist to another.

61. This results in delayed identification or, worse, nonidentification . A better solution is for the regional dental associations to implement standardized codes for various surfaces of the teeth as well as treatments performed.

62. DENTAL COMPARISON AND IDENTIFICATION UNIT E limination of identification / confirmation. Done once all the post-mortem information is available. All ante-mortem data may or may not be available. Manually or by computer aid. When there is a match, one must ensure that all sets of documents relating to dental features are attached to the relevant sets of documents for the rest of the body.

63. Computer software programs have also been developed to simplify comparison. However, the final identification should always be done by the dentist manually. co-operation between different identification teams-success.

64. Ante-mortem dental records are not traceable. Dental profiling includes extracting a triad of information 1. T he decedent's Ethnic origin 2. Gender 3. Age. DENTAL PROFILING

65. I. Identifying Ethnic Origin from Teeth. Physically, humans are a diverse species. This diversity is a result of genetic influences, as well as environmental factors . The people of the world look different. Traditionally, the human species has been categorized into three 'races'­ Caucasoid, Mongoloid, and Negroid.

66. Facial # of the living are reflected in the underlying sk str. Nasal aperture of the Negroid skulls may be broad. Negroid palate-u shaped, broad with protruding ant teeth. Mongoloid-larger prominent cheek bones.

67. GENETIC AND ENVIRONMENTAL INFLUENCES ON TEETH D ifferent populations show considerable diversity in their dentition and several features have been grouped accordingly. Dental features used to describe population differences are broadly categorized as metric and non metric. DP

68. Metric features are based on measurements , and non­metric in terms of presence or absence of a particular feature, e.g. whether Carabelli's cusp is present or not. Metric features are considerably influenced by 'local' environmental factors On the other hand, Non Metric features are more heritable, therefore, dependable

69. NONMETRIC DENTAL FEATURES More than 30 nonmetric features of the tooth crown and root have been described and analyzed in detail by Scott and Turner II. Crown Features Shovelling . Double shovelling . Carabelli's feature. Three-cusped upper 2nd molar. Winging - bilateral labial rotation of the lower molar groove pattern. ('X,' 'Y' and '+') DP

70. Lateral incisor variants: Include peg shaped, diminutive and T-forms Parastyle : Tubercle on the buccal surface of the upper molars. Protostylid : The presence of a tubercle on the mesiobuccal cusp of the lower molars -lower first molar

71. ROOT FEATURES Two-rooted upper premolar. Two-rooted upper molar. Two-rooted lower canine. Tomes root: Presence of an extra root on the lower first premolar. Three-rooted lower molar.. Single-rooted lower molar. DP

72. EUROPEAN, WEST- AND SOUTH-ASIAN ORIGIN four-cusped lower second molar two­rooted lower canine Carabelli's feature three­cusped upper second molar EAST-ASIANS Winging Shovelling double-shovelling interruption grooves enamel extensions three-rooted lower first molar three-cusped upper 2 nd molar single-rooted lower second molar DP

73. 2. Sex Differentiation B ased on data from morphology of skull & mandible, metric features, as well as by DNA analysis of teeth . Skull & mandible : Male larger, orbits square, nasal apertures higher & narrower with sharp margins Female -forehead is more vertical so ridges are min in size & may be much more rounded Bones of skull DP

74. CRANIOFACIAL DIMENSIONS A re not reliable until well after puberty. A ffected by old age changes. L ateral cephalometric tracings-99 per cent success Max length of the skull- In general, the male skull is larger, with an endocranial volume about 200cc more than that of females. DP

75. Md angle-90% accurate Male angle of md shows a marked roughened/ridged app & lower border of the angle of the md may deviate lat to a marked extent in males F-rounded & gracile in construction, attachment of m is smoother. Muscular f may show male changes & VV

76. Mastoid process- larger, prom & more roughened in males. Other # male skull - larger occipital condyles - larger & broader U- shaped palate - heavier & more laterally arched cheek bones. DP

77. SEX DIFFERENCES IN TOOTH SIZE Studies show significant differences between male and female permanent and deciduous tooth crown dimension T ooth size, or odontometrics , is under considerable influence of the environment. The canines consistently show the maximum sex difference. Premolars, first and second molars as well as maxillary incisors are also known to have significant differences. DP

78. TOOTH MORPHOLOGY AND SEXING 'Distal Accessory ridge', a nonmetric feature on the canine "is the most sexually dimorphic crown trait in the human dentition, with males showing significantly higher frequencies and more pronounced expression than females". G reater absence of the distobuccal cusp or distal cusp on the mandibular first molar in females (40.6 per cent) compared to males (16.2 per cent) in a south Indian population. T he reduction in the number of cusps is a reflection of an evolutionary trend towards overall reduction in the size of the lower face, with males apparently resisting this trend. DP

79. DENTAL INDEX In addition to absolute tooth size, tooth proportions have been suggested for differentiating the sexes . AITCHISON - 'INCISOR INDEX' Ii = [MDI 2 / MDI 1 ] X 100 Higher in males DP

80. The 'Mandibular Canine Index' by Rao Using the mesiodistal dimension of the mandibular canines 7.1 mm is the maximum possible mesiodistal dimension of mandibular canines in females . The same dimension is greater in males. 89 per cent success The odontometric difference between males and females is generally explained as a result of greater genetic expression in males. DP Mean m-d canine dimension in female + S.D. + Mean m-d canine dimension in males - S.D. 2

81. SEX DETERMINATION BY DNA ANALYSIS CDI DNA is a robust mol which can tolerate a remarkable range of temp, pH, salt & other factors that destroy classical serological markers. Validation testing has shown that DNA mixed with detergents, oil, gasoline & other adulterants did not alter its typing cha . Indeed it is this ruggedness which allows DNA longevity & has permitted DNA typing of Egyptian mummies & 30 million year old insects preserved in amber . Decedent’s ante-mortem sample is unavailable, the DNA pattern may be compared to a parent or to a sibling

82. Forensic DNA analysis for sex determination can give highly accurate results. H air from a hairbrush, epithelial cells from a toothbrush Sex can be determined with very minute quantities of DNA (as little as 1Opg), and from very old specimens of teeth. PCR allows amplification of even highly degraded DNA.

83. Types of DNA: Genomic or Nuclear DNA : Commonly used in forensic cases. Mitochondrial DNA ( mtDNA ), While any given cell has a single nucleus, each cell has a high copy number of mtDNA , e.g. epithelial cells contain 5000 mtDNA molecules. substitute CDI

84. Sivagami and coworkers state, " amelogenin (AMEL) is one of the major matrix proteins secreted by the ameloblasts of the enamel. The AMEL gene, coding for a highly conserved protein, is located on the X- and the Y-chromosomes in humans. The two alleles are similar for the exonic sequences but differ in the intronic sequences. Thus the females (XX) have two identical AMEL genes but the males ( XY) have two nonidentical genes.

85. Certain dyes having an affinity Y chromosome which may be made fluorescent under microscope. CDI

86. RFLP (restriction fragment length polymorphism )/ southern blotting: -limited value in cadaveric tissue unless the remains are fresh since DNA rapidly breaks down after death. Dot/blots: sequence info can be obtained by DNA probes (small piece of single stranded DNA which will bind to another with the complementary sequence ) - rapid, reasonably well - on degraded samples. STRs/short tandem repeat: significant degradation, quite amenable to automation CDI

87. 3. Dental Age Estimation The final step in the triad of dental profiling different physiologic systems are used to estimate age Size of the skull Closure of symphysial suture Fontanelles Hand wrist X rays Teeth are considered better suited than bones. Dental age is one of the few measures of physiologic development that is uniformly applicable from infancy to late adolescence. DP

88. APPLICATION OF AGE ESTIMATION: Treatment planning Legal applications- - crime investigation -school admission -marriage -employment Living DP

89. Dental age estimation makes use of morphologic, radiographic, histological, and biochemical methods to examine age dependant changes in teeth Age estimation using the dentition may be grouped into three phases: Ageing in prenatal, neonatal and early postnatal Age estimation in children and adolescents -first 2 decades (teenage) -3 rd molars in age estimation Age estimation in adults. 2 imp events Calcification & Emergence of dec & perm teeth Calcification is preferred & is reliable compared to emergence DP

90. Emergence is a convenient clinical method-It involves visual assessment of teeth present in the mouth and requires little expertise or equipment. The use of tooth emergence for age estimation should, however, be limited to deciduous teeth . Their emergence is under genetic control and is relatively regular On the other hand, emergence patterns of permanent teeth are under the influence of the intraoral environment , being affected by infection, arch space, and premature tooth loss. DP

91. Therefore, evaluation of radiographs to assess tooth calcification is a much better alternative since calcification of teeth can be observed from radiographs for a period of Several years It is not altered by local factors such as lack of space, infection, etc., And the study of tooth calcification also lets us assess age at periods when no emergence takes place (2.5-6 years and > 12 years). DP

92. 1. AGE ESTIMATION IN PRENATAL, NEONATAL AND EARLY POSTNATAL CHILD. The primary tooth germ begins to form at seven weeks in utero , and the enamel formation of all deciduous teeth is usually complete by the first year. Among the permanent teeth, the first molar shows germ formation first at about 3.5-4 months - accurate DP

93. Jaw of 26 week fetus Jaw of 30 weeks fetus Mineralisation of tooth germs-well advanced in ant, crypt of 1 st dec molar min outline of 2 cusps r seen, 2 nd dec M-min of 1 cusp is visible, as this process starts at about 6 months of IU life this child was about 26 weeks from conception at the time of death. More min of ant, 2 nd dec M contains a tooth with 5 cusps which r beginning to min but still are widely separated , 1 st dec M cusps r beginning to fuse but still r not completely united , a # which suggests that fetus has not reached full term & is probably 30 weeks from conception

94. Absence of teeth-<6 mon Variable 1 dec M-all the cusps fused 2 nd dec M-min & fused but not completely Crypt of 1 st perm M-one of the mesial cusps have started to mineralize indicates a new born infant. DP

95. Histological techniques- which enable observation of tooth mineralization up to 12 weeks before it is actually apparent on radiographs. However, this requires specialist training. But radiography has advantage that it is 'noninvasive', requiring no tissue dissection. DP

96. The ‘Neonatal line' is considered as an indicator of birth. Bowers attributes its formation to the slowing down of enamel prism growth rate , thus ‘creating an apparent line of demarcation’. According to CiapparelIi , the neonatal line may take up to three weeks after birth to form. DP

97. Hence, false result may be produced when one concludes that the absence of the neonatal line proves that the individual was ' stilIborn '. What is certain, however, is that if the neonatal line is present, it indicates a live birth. Estimating age in this age group may have legal implications in cases that involve F oeticide and Infanticide . DP

98. First 2 decades of life: Putrefied body Incisor is almost complete, 1 st perm molar showing min in one of the cusps Histological sections of the incisor from the same pt shows that the degree of root dev confirms the age of 3 months after birth DP 2. Age Estimation in Children and Adolescents

99. 1 st permanent molar has erupted & the radiograph showed the pre of dev 2 nd molar- confirming the age of 7-8 years. Resorption of deciduous teeth-Mixed dentition period DP

100. Dentine translucency Bang and Ramm - First used for estimating age and reported significant increase in root translucency with age . Root dentine starts to become translucent during the third decade of life . Hence, the difference in refractive indices between intratubular organic and extratubular inorganic material is equalized, resulting in increased translucency of the affected dentine. DP

101. For age estimation, Solheim suggested translucency length (in mm) or area (in mm2) may be measured on intact or sectioned teeth. These variables may be measured either manually or by computer image analysis. Length of translucency had a greater correlation to age, for which two equations were given: for zones of translucency ≤ 9 mm, and for zones > 9 mm, where Bo is a regression constant, B1 and B2 are regression coefficients, and X is the translucency length. Age = B o + B 1 X+B 2 X 2 Age = B o + B 1 X DP

102. When sections of teeth cannot be prepared, cut through a standing permanent tooth. DP

103. DISADVANTAGES : Irregular junction of translucent and non­translucent zones, thereby making it difficult to measure the length. Underestimation of age in older age groups. This could be due to slowing down of dentinal sclerosis, since most of the root would already be sclerosed by old age, thus restricting further increase in translucency. DP

104. Incremental lines of cementum. U se of mineralized, unstained cross-sections of teeth, preferably mandibular central incisors and third molars. A n accuracy of within two to three years of the actual chronologic age. However, the pathologic state of the periodontium and/or desmodontium may compromise the precision of ageing. DP

105. In addition to age, hypo mineralized bands in these incremental lines gave an indication of events such as pregnancies, skeletal trauma, and renal disorders , which could be accurately dated to an individual's life-history, thus facilitating identification. A major disadvantage of the above methods of estimating age in adults is the necessity to extract and/or section the teeth. While this is possible in the dead, it is not practical among living adults DP

106. RADIOGRAPHIC METHOD OF KVAAL AND ASSOCIATES. N ondestructive technique, used pulp size measurement of six teeth M axillary central and lateral incisor, Second premolar; Mandibular incisor, Lateral incisor, Canine , and First premolar observed on periapical radiographs. The measurements included several length and width ratios used in order to compensate for magnification and angulation errors of teeth on the radiograph. DP

107. pulp-root length (P) pulp-tooth length (R) tooth-root length (T) pulp-root width at CE] (A) pulp-root width at mid-root level (C) pulp­root width at mid-point between level C and A (B) M ean value of all ratios excluding T (M) M ean value of width ratios Band C (W) M ean value of length ratios P and R (L). When six teeth (right or left side) from both jaws are available, the following regression formula can be used: Age = 129.8-316.4(M)-66.8(W-L). DP

108. AMINO ACID RACEMISATION R elationship between dentinal age and the extent of aspartic acid racemisation in dentine. All humans use amino acids exclusively in protein synthesis. Aspartic acid is an amino acid that has a rapid rate of racemisation , i.e. it gets spontaneously converted from one type ( L­aspartic acid) to another (D-aspartic acid) with increasing age. DP

109. Therefore, there is a constant change in the ratio of L- and D-aspartic acid at different ages and this D-L ratio may be used for age estimation. D-L ratio can be measured in those proteins that are synthesized early in life and are not replaced. Such proteins are found in brain cells, bone and teeth. Racemization rate of aspartic acid is high in root dentine. E stimates age within plus/minus three years of the actual age.

110. OTHER METHODS Spectroradiometry - objective method for dentine color measurements . Dentinal colors white, cream, and yellow - associated with age 12-37 years while dark yellow and brown were associated with the age-group 55-64 years. Color changes in the dentine and cementum may be caused by infusion of decomposition products from erythrocytes such as PORPHYRINS , which fluoresce. There is a strong correlation between deepening of the tooth color (i.e. increased yellowing of the roots) and increase in fluorescence intensity with age. DP

111. The keys to optimal dental age estimation suggested by Williams and associates : The investigator should be sufficiently experienced . 2. Multiple investigators or a second opinion is important. 3. Use of multiple age estimation methods . 4. Careful adherence to suggested protocol , including use of specific equipment and proper storage of tooth specimens. 5. Use of multiple teeth . DP

112. CRIME INVESTIGATION A vital role the forensic dentist plays is in Criminal investigation Includes: the investigation of LIP PRINTS BITE MARKS CHILD ABUSE

113. Tsuchihashi named the wrinkles and grooves visible on the lips as ' Sulci labiorum rubrorum '. The imprint produced by these grooves is termed 'lip print' the examination of which is referred to as ' Cheiloscopy '. These grooves are heritable and are supposed to be individualistic. Lip prints

114. Lip prints were first classified by Santos : Simple wrinkles . Straight line . Curved line . Angled line . Sine-shaped curve Compound wrinkles . Bifurcated . Trifurcated . Anomalous

115. Tsuchihashi later proposed a separate classification: Type I. Clear-cut vertical grooves that run across the entire lip. Type II. Similar to Type I, but do not cover the entire lip. Type III. Branched grooves. Type IV. Intersected grooves. Type V. Reticular grooves. Type VI. Grooves that cannot be morphologically differentiated.

116. A combination of these grooves may be found in any given set of lips. Lips are divided into quadrants similar to the dentition-a horizontal line dividing the upper and lower lip and a vertical line dividing right and left sides. By noting the type of groove in each quadrant, the individual's lip print pattern may be recorded.

117. lipsticks have been developed that do not leave any visible trace after contact with surfaces such as glass, clothing, cutlery, or cigarette butts Alvarez and associates - 'persistent ' lip prints. Can be 'lifted' by aluminium powder and magnetic powder. Use of lipsticks is not indispensable for leaving lip prints-Ball states that the vermilion border has minor salivary glands, and the edges of the lips have sebaceous glands, with sweat glands in between. One may, therefore, assume that secretions of oil and moisture from these enable development of 'latent' lip prints, analogous to latent fingerprints, in most crime scenes where close contact between the victim and culprit has occurred.

118. Distinct lip lines+well marked grooves+ an area of abnormality-mirror image

119. However, a major disadvantage pertains to uncertainty about the permanence of Lip patterns. Major trauma, pathosis and the surgical treatment rendered to correct the pathosis , affect the size and shape of the lip, thereby may alter the pattern and morphology of the grooves. T he prints produced may differ in appearance depending on the pressure applied and its direction. Hence, lip prints caused by one individual may be mistakenly identified as those from another. Therefore, this sub-specialty of forensic odontology required further study-first, to comprehensively establish the uniqueness of lip grooves.

120. BITE MARKS Defined by MacDonald “a mark caused by the teeth either alone or in combination with other mouth parts". Biting is considered to be a primitive type of assault and result when teeth are employed as a weapon in an act of dominance or desperation. Can be caused by humans or animals; they may be on tissue, food items, or other objects.

121. Broad, U-shaped and some­what circular or oval Narrow in anterior aspect and is V-shaped and elongated Human bite marks have broad central and relatively narrow lateral incisors and are blunt & superficial. Bite marks caused by animals exhibit broad laterals , narrow central and sharper and deeper canine marks. Deep & tearing. present on breast, abdomen, nipple, thigh, back and shoulders in case of sexual assault and the extremities in a fight and violence present on exposed skin surfaces and extremities. HUMAN ANIMAL

122. cat dog monkey human

123. MacDonald suggested an etiologic classification. pertinent to human bite marks Tooth pressure marks : direct application of pressure by teeth. Tongue pressure marks. Tooth scrape marks : anterior teeth, and present as scratches or superficial abrasions.

124. WEBSTER'S CLASSIFICATION Bite marks in foodstuffs, especially in cases of theft or robbery, where the involved may conveniently grab a bite from the kitchen refrigerator or the supermarket food shelf. Type I. The food item fractures readily with limited depth of tooth penetration, e.g. hard chocolate. Type II. Fracture of fragment of food item with considerable penetration of teeth, e.g. bite marks in apple and other firm fruits. Type III. Complete or near complete penetration of the food item with slight marks , e.g. cheese.

125. BITE MARK APPEARANCE Type of Injury: Compression of the skin surface due to tooth pressure during a bite causes indentations initially. Indentations, while ideal for bite mark analysis, seldom persist for more than a few minutes unless the victim is dead. Owing to the elastic nature of skin, indentations soon disappear as the skin regains its original contour. This is followed by a brief period of edema over the bite area, which usually obscures the bite mark completely.

126. Once the edema subsides, subcutaneous bleeding is apparent. These are referred to as contusions or bruises, and are the most common presentation of bite marks in criminal investigations. They appear as reddish/purplish discolorations on the skin surface, a result of blood escaping into the subcutaneous tissue from ruptured vessels. When the intensity of the bite is great, there may be a break in the integrity of skin surface, resulting in lacerations . The most extreme form of bite mark injury is avulsion , where part of the tissue is bitten off.

127. Compression of skin-Tooth pressure -causes indentations edema contusions or bruises ( SC bleeding- bluish/purplish ) When the intensity of the bite is great, there may be a break in the integrity of skin surface, resulting in lacerations . The most extreme form of bite mark injury is avulsion , where part of the tissue is bitten off. Few min Elastic nature Brief period obscures

128. FEATURES OF HUMAN BITE MARK: Class features. The pattern present in the bite mark may vary in size and shape. This enables one to differentiate between different types of teeth. Incisors produce rectangular marks Canines are triangular or rectangular , depending on the amount of attrition Premolars and Molars are spherical or point- shaped . Individual features. Class features may, in turn, have characteristics such as fractures, rotations , etc. Such features are known as individual features and they make the bite mark distinct.

129. Bites and Child Abuse Child abuse may be broadly categorized as physical abuse, sexual abuse, emotional abuse, and neglect of the child. One must also remember that children may bite each other casually during play.

130. Visual Examination . Type of injury- petechiae , contusion, abrasion, laceration, incision, avulsion Contour, texture, and elasticity of the bite site Physical appearance (color and size), orientation, and location Differences between upper and lower arches, and between individual teeth . Photography : provide a permanent record of the appearance of bite marks. No time should be lost in obtaining photographs, as the injury rapidly changes appearance due to healing. Examining a bite mark:

131. Saliva deposited on skin may have WBCs and sloughed epithelial cells . These are a potential source of DNA , thus enabling a direct link to the suspect. Care should be taken not to wash the bite area before saliva swabbing. A cotton swab moistened with distilled water should be used for swabbing. This rehydrates the dry cells in the bite area. The swab is then labeled and stored in a refrigerator. The latter prevents degradation of salivary DNA and bacterial growth. If the bite has occurred through clothing, the clothes must also be swabbed for saliva. The use of high intensity alternative light source (such as UV light ) to locate stains from body fluids enable saliva traces to be recovered even in the absence of visible bite marks. Saliva Swab.

132. Impressions. Impression of the bite area should be made when tooth indentations exist. The material of choice is Vinyl Polysiloxane . The impression material should be reinforced with dental stone, self-cure acrylic, or impression compound to prevent against dimensional change.

133. It is to be noted that if the bite mark is on an area accessible to the victim's own dentition. impressions of the victim's teeth should be made for suspected self-inflicted bites .

134. EVIDENCE COLLECTION FROM THE SUSPECT. I nformed consent or a court order (warrant). The items of evidence recovered should include : Photographs of the suspect's teeth, in occlusion and in open bite. Maxillary and mandibular impressions made with rubber-based material, and models poured in dental stone. It is advisable to pour at least two casts of the suspect as a back-up.

135. Test bite media Wax exemplars: A luwax , base plate wax Styrofoam Volunteers skin Fruits Clay Bite registration in centric occlusion using a thin sheet of wax. Saliva swab

136. BITE MARK ANALYSIS AND COMPARISON The dynamics of biting make analysis of the bite mark and its comparison to the suspect's teeth challenging. In addition to jaw movements, one needs to consider movement on part of the victim, the flexibility of the bitten tissue, as well as distortion introduced during photography. Bearing this in mind, one may proceed with the analysis.

137. Tech aids employed for analysis: - T ransillumination of tissue -Computer enhancement &/or digitization of mark &/or teeth -Stereomicroscopy &/or macroscopy -SEM -Videotape -Caliper for measurement

138. Silicone rubber impression

139. It is important to consider uncommon characteristics of the bite mark such as presence or absence of a particular tooth, mesiodistal dimension, rotation, fracture, diastema, and other unusual features of the teeth, as these may help in implicating a suspect.

140. The measurement of the mark constitutes 'metric analysis', and may be obtained using simple instruments such as a vernier caliper or using software programs. Measurements obtained from the bite mark should be compared to that of the suspect's dental model.

141. Metric analysis, ideally, should not be used alone, but in conjunction with 'pattern association', which involves matching the pattern of bite injury to the arrangement of teeth in the suspect's dentition. Ciapparelli and Hughes have described 'direct methods' of comparison , where the suspect's models were placed directly over the bite mark photograph or on the bite mark itself, i.e. in situ . the incisal and occlusal edges of the suspect's teeth were traced onto clear acetate and superimposed on life-sized bite mark photographs. This constitutes the indirect method.

142. Variations of the prototypical BM Drag marks- slipping of teeth against the skin/by imprinting of the lingual surface of the teeth Double bite- a bite within a bite Peripheral ecchymosis - excessive confluent bruising Partial bite marks- one arched, one/few teeth, unilateral-due to incomplete set of teeth, uneven pressure/skewed bite

143. Indistinct/faded bite marks : - Fused arches: collective pressure of teeth, no indi tooth marks - Solid: ring pattern is not apparent coz erythema /contusion fills the entire center leaving a filled, discolored, circular mark - Closed arches: joined at their angles Latent - seen only with sp imaging tech Superimposed/multiple bites Avulsive bites

144. Terms indicate degree of confidence that an injury is a bite mark: Possible BM : an injury showing a pattern that may/may not be caused by teeth Criteria : -gen shape & size are pre but distinctive # such as tooth marks are missing -incomplete, distorted/a few marks resembling tooth marks are pre but arch configuration is missing

145. Probable BM: the pattern suggests/supports origin from teeth but could conceivably be caused by something else Cri: pattern shows some, basic, gen cha of teeth arranged around arches Definite BM: there is no reasonable doubt that teeth created the pattern, other possibilities were considered & excluded Cri: pattern conclusively illustrates (classic #, all the cha, typical class cha) of dental arches & human teeth in proper arrangement so that it is recognizable as an impression of the human dentition

146. Comparison microscope -device allowing 2 sections or specimens to be viewed simultaneously so that a correlation can be tested b/w the two. However, the trend today is moving towards the , use of computer software programs suggested by ; Johansen and Bowers. A 3-D/CAD supported , photogrammetry approach developed by Thali and holds promise for the future.

147. Thickness of Soft ti overlying the bones of the skull does not vary greatly b/w individuals. Contour & thickness of the mu of facial expression are added in mod clay, care being taken not to exceed the thickness designated by the wooden pegs. Spaces b/w the mu are filled in with clay to represent c/t, finally the skin contour is added. In pic the deviated nasal septum-rt

148. Superimposition of a facial photograph over a skull photograph printed to exactly the same size & orientation- real legal cases in 1930s The method enabled to distinguish b/w 2 diff women.

149. THE DENTIST AS AN EXPERT WITNESS Forensic dentists, who are associated with identification and crime investigation, are usually required to provide testimony in the court of law in the capacity of an 'expert witness'. i.e. an expert witness is one who gives an opinion on facts that fall within the realm of his/her particular profession or specialization.

150. the expert witness may appear for the prosecution or for the defense. questioning by the lawyers of the opposing side cross-examination The opposition counsel may indulge in character assassination, trying to weaken the expert witness and the evidence that is presented. It is advisable to control one's temper, keep calm, and be dispassionate.

151. and should never try to guess answers, or answer questions that are beyond one's expertise. To do so could be disastrous, with the opposing lawyer taking full advantage to undermine the expert's credibility. Opinion should be presented in such a way that it is accurate and yet simple enough for the layman to understand. never to discuss matters pertaining to a case with anybody To summarize, the expert witness in particular and the forensic dentist in general, must be professional, unbiased, ethical, and truthful

152. “In nature’s infinite book of secrecy a little I can read”