Bite Marks (FORENSIC DENTISTRY)

Bite marks

1. PEDODONTICS SEMINAR PRESENTED BY: GUIDED BY: CHRISTY KOSHY DR. VIKRAM SINGH RATHORE (FINAL YEAR) DR.VANISHA SINGHVI DR. VARSHA PARIHAR BITE MARKS

2. CONTENTS INTRODUCTION DEFINITION CLASSIFICATION FACTORS INFLUENCING APPEARANCE OF BITE MARK BITE MECHANISMS IDENTIFICATION ABFO GUIDELINES PROCEDURE CONCLUSION BIBLIOGRAPHY

3. INTRODUCTION Biting is considered to be a primitive type of assault Associated with sex crimes, fights, child abuse SORUP, 1924 was the first to publish an analysis of bite mark Musculature of the lips , tongue, cheeks, mental state of the biter play an important role AGE GROUP IN CHILDREN: Female children: 11-15 yrs Male children: 4-10 yrs

4. DEFINITION BITE MARK: Mc Donald 1972: “A mark caused by the teeth either alone or in combination with other mouth parts” BITE: is to tear or seize with the tooth TOOTH MARK: produced by 2 or more teeth ARCH MARK: 4 OR 5 marks of adjacent teeth must be present before a mark can be identified as a human arch mark

5. Tooth scrape Tongue pressure marks Tooth pressure marks Classification Mc Donald’s classification CAMERON & SIMS’ CLASSIFICATION . AGENTS . MATERIALS HUMAN SKIN, BODY TISSUE ANIMAL FOODSTUFF OTHER MATERIAL

6. FactorS Influencing appearancE of bitemark Vascularity : bruising of loose highly vascularised skin is more pronounced S ex : women bruise easily than men Age : children & ealderly bruise easily Medication: such as aspirin bleeding Normal skin color Time of injury Mass & velocity of impact

7. BITE MECHANISMS Tooth pressure : direct application of incisal edges of anterior teeth or occlusal surface of posterior teeth Common in battered child syndrome Tongue pressure : when material is into mouth & pressed by tongue against lingual surface of teeth or palatal rugae Tooth scrape: by scraping of teeth across the surfaces of skin. Present as scratches or abrasions

8. Tooth scrape

9. IDENTIFICATON Sweet suggested that a bite mark may be identified by the following: GROSS CHARACTERISTICS Circular or elliptical pattern with central area of ecchymosis circular- caused by upper & lower arches ecchymosis - due to sucking action

10. CLASS CHARACTERISTICS INCISORS: Rectangular marks CANINE: Triangular or Rectangular PREMOLARS & MOLARS: spherical or point shaped INDIVIDUAL CHARACTERISTICS May have features such as fractures, rotations, spacing etc which make bite mark distinct

11. ABFO GUIDELINES American Society Of Forensic Odontology Protocol for bitemark analysis , 1993 # Description of the bitemark #Collection of evidence from victim -Photography -Impression -Salivary swab -Tissue samples # Collection of evidence fro the suspect -Dental records -clinical examination -photography -impression #Comparing the bitemark

12. PROCEDURE Description of bite mark: Demographic description -Anatomical location including surface, contour, color,shape , size

13. Collection of evidence from victim : Photography : safest means of obtaining a permanent record of marks Shots would include : With or without ABFO no.2 scale In color and black & white On and off camera flash An overall bodyshot showing the location of injury Close ups Uv photography if the injury is fading If bite is on movable anatomical location, various body positions adopted

14. SALIVARY SWABBING The amount of saliva deposited with a bite mark is about 0.3 mL & distributed over wide area of 20cm TWO SWAB PROTOCOL Saliva : source of DNA of the suspect Care should be taken not to wash the bite area before swabbing FIRST sample: rub the bitten area with a moist cotton swab This rehydrate the dry cells in the bite area 2. Bitten mark is rubbed with a second dry cotton swab 3. The swabs are air dried in room temperaure for 30 mins

15. Placed in labelled paper envelope & stored under refrigeration before submission to lab clothing must also be swabbed if bite has occured through it Use of uv light enable recovery of saliva traces in the absence of visible bite mark

16. CIGARETTE PAPER METHOD : 1 cm 2 of cigarette paper held in forceps is used after wetting it with distilled water Whole bite mark swabbed with light pressure in circular motion Air dry the paper by placing it on clear microscopic slide and sent to laboratory Saliva obtained is used to determine blood group Ag

17. IMPRESSION & STUDY CASTS Rubber base and silicone base impression materials are used. Method I : Pour the material covering bite area. Place wire gauge & inject additional material over it. Method II: Special tray constructed using cold cure confining to the shape of bite mark & impression is made. Master casts poured with type IV stone & duplicate casts should be made.

18. Collection of evidence from the suspect : Only after legal consent has been obtained Includes photographs, saliva samples, casts

19. BITE MARK ANALYSIS Measurement: metric analysis using Vernier caliper or computer software Metric analysis: matching of bite injury to the teeth arrangement in suspects dentition Nowadays adobe photoshop have developed 3D/CAD supported photogrammetry .

20. Recent advances: Xeroradiography Transillumination Videotape analysis Superimposition technique Scanning microscopy

21. CONCLUSION As suggested by Levine & ABFO DEFINITE BITER: There is reasonable medical certainity to indicate that the bitemark has been produced by suspects dentition. There is no unexplained discrepancies PROBABLE BITER: bite mark shows some degree of specificity to the suspect’s teeth by virtue of a number of matching points POSSIBLE BITER: although the suspects dentition could have made the mark, there are no characteristics matches to be absolutely certain. The similarity is non specific. NOT THE BITER: the bite mark & the suspects dentition are not consistent features on the bite mark shows that suspects teeth have definitely not caused them.

22. BIBLIOGRAPHY Textbook of pediatric dentistry, Nikhil Marwah (fourth edition) Textbook of pedodontics , Shobha Tandon (third edition) Shafer’s textbook of oral pathology (seventh edition) Oral and maxillofacial pathology, Neville (third edition)