From Annals and Essences of Dentistry
METHODS OF IDENTIFICATION IN FORENSIC DENTISTRY
Ratnakar.P*Singaraju. G.S.***Profesor , Department of Oral medicine , Mookambica institute of dental sciences, Padanilam, Kanyakumari, Tamilnadu* * Profesor , Department of Orthodontics , St. Joseph Dental College Eluru, , A.P. (Both the authors are ex-Readers at CKS Teja Institute of Dental science, Tirupati, A.P.
The subject of Forensic Odontology has been generating as an area of emphasis for all interested and properly trained dentists in all hazards response. Many States have recognized the role of forensic dentist in the areas of emergency/hazard readiness. Forensic Odontology or Forensic Dentistry has been a discipline within the oral medicine fold and has been a well-accepted role for dentists. When the Tsunami in the Tamilnadu in 2001 and Bomb blasts in Mumbai in 2008 struck the people , another facet in the role of dentists and dentistry in emergency response as a forensic expert came to the collective consciousness of oral health professionals. The dentists participating in such events should be properly trained to have a meaning full role in disaster response. The dental evidence in forensic investigation is legally accepted. However there are certain pitfalls associated with the various methods in forensic dentistry. In this review various methods employed in the forenic odontology for personal identification such as Bite marks, Cheiloscopy , Rugoscopy , photographs and radiographs are discussed.              
forensic odontology, rugoscopy ,cheiloscopy.
The word forensic comes from the Latin word forensis: public; to the forum or public discussion; argumentative, rhetorical, belonging to debate or discussion1. From there it is a small step to the modern definition of Forensic in adjective form used or applied in the investigation and establishment of facts or evidence in a court of law . Forensic dentistry is the branch of dentistry that deals with the legal aspects of professional dental practices and treatment, with particular emphasis on the use of dental records to identify victims of crimes or accidents. Forensic dentistry plays an important role in mass disasters(terrorist attacks, earthquakes, Tsunamis),, child/elder/spouse abuse, bite mark analysis, criminal/natural deaths and injuries, Bioterriorism etc.., It also helps in identification of decomposed and charred bodies like that of drowned persons, burns, and victims of motor vehicle accidents. The different methods employed in in forensic dentistry include Bite mark analysis, tooth prints, Rugoscopy, Cheiloscopy, Dental DNA analysis, Radiographs, Photographic study etc..,. In this article, the various methods employed in forensic dentistry are discussed.
The study of palate in general is called as Palatoscopy and the The study of the patterns of the grooves and ridges (rugae) of the palate to identify individual patterns is called as Rugoscopy. Palatal rugae comprise about three to seven ridges radiating out tangentially from the incisive papilla. Venegas 2 et al determined the shape, size, number and position of the palatal rugae. The most prevalent palatal rugae shape was sinuous followed by curve , line, point and polymorphic varieties . The palatal rugae that were larger were the sinuous. The pattern of these rugae is considered unique to an individual and can be used as reliable method in postmortem cases. The shortcomings in applying rugoscopy as a definitive tool in forensic odontology are many. Postmortem identification is not possible without the antemortem records. To give rugoscopy such importance, previous recording, scanning and preservation through dental casts and computer records are essential. Kapali et al. 3 have observed that denture wear, tooth malposition, and palatal pathology can cause alterations in rugae patterns. Thomas and kotz 4 from their studies concluded that different patterns of rugae are genetically determined, and so can be rather used in population differentiation than individual identification. palatal rugae are often destroyed in fire accident cases and in those cases of decomposition and thus rugoscopy does not have application after this stipulated period. 5
Lip prints (cheiloscopy)
Lip prints are normal lines and fissures in the form of wrinkles and grooves present in the zone of transition of human lip, between the inner labial mucosa and outer skin, examination of which is known as cheiloscopy6. Lip prints are unique for individuals like the finger prints. Suzuki and Tsuchihashi, in 1970, devised a classification method of lip prints, which is as follows7:
- Type I - A clear-cut groove running
vertically across the lip.
- Type II - Partial-length groove of Type I.
- Type III - A branched groove.
- Type IV - An intersected groove.
- Type V - A reticular pattern.
- Type VI - Other patterns.
Lip print recording is helpful in forensic investigation that deals with identification of humans, based on lip traces. A lip print may be revealed as a surface with visible elements of lines representing the furrows. This characteristic pattern helps to identify the individuals since it is unique for individuals. One common problem that is encountered during the cheiloscopic studies is that of smudging or spoiling of lip prints leading to unidentifiable marks When the lines are not clear (Only the shape of lines is printed), individual identification of human being based on this trace is extremely difficult, unless the trace contains more individual characteristics like scars, clefts etc, and often identification ends with group identification.7,8
Bite mark analysis
The science of identification of bite mark identification can be used to link a suspect to a crime. Bite can be defined as the mark made by human or animal teeth in the skin of alive people, cadavers or unanimated objects with relatively softened consistence9 . Bite marks depending upon the crime or circumstances are impressions left on food, skin or other items left at a scene. In assault cases they may be found on the victim. Besides the agent identification, bite mark analysis, in a forensic investigation, can elucidate the kind of violence and the elapsed time between its production and the examination. It can show if the bite was produced intra-vitam or post-mortem and, in case of several bite marks, identify the sequence of them9. The identification of the perpetrator can also be done by the determination of ABO blood groups from the saliva on the bite mark, and linking bacteria and other microorganisms found in the bite mark to the oral milieu of the perpetrator. Newer techniques that have enhanced bite mark identification include application of electron microscopy and computer enhancement technique. However, bite marks do not embody all the requisites of an ideal identification method (unicity, immutability, practicability, classificability), but it can represent, in some cases, the unique signs of real value to criminal investigation 10.There are many drawbacks of bite mark analysis. The size of the bitemark may shrink in size in a relatively short duration (10-20 minutes) and this necessitates their recording at the earliest possible time. 6Incomplete bite marks are not conclusive and a minimum of four to five teeth have to be present for reliable bite mark analysis.
The utilization of radiographs in identification is valuable if sufficient antemortem records are available. Various morphological and pathological alterations can be studied from the radiographs. Crown and root morphology aids in identification. The presence of decayed, missed, filled, and fractured teeth, various stages of wound healing in extraction sockets, degree of root formation, and bone trabecular pattern in the jaws aid in identification. However in countries like India antemortem records are meagre and incomplete or improper.
Dental structures are relatively more resistant to higher temperatures . Techniques involving DNA in Forensic Dentistry offers a new tool when traditional identification methods fail due to the effects of heat, traumatism or autolytic processes, as well as in distortions and difficulties in analysis12.They can provide a source of DNA for easy identification. Due to this abundance of material, the use of the technique based on PCR (Polymerase Chain Reaction) has acquired great importance in DNA post-mortem analysis in forensic cases. Polymerase Chain Reaction is an enzymatic amplification of a specific DNA sequence, aiming millions of copies production from this sequence in a test tube, which was first described by Kary Mullis, in the late 1980's, and enabling a new strategy of gene analysis though a simple and fast method, excusing all the laborious stages of genic cloning12. The method using PCR enables the distinction of a subject among the other ones with a high level of reliability, starting by 1ng (nanogram), equivalent to a single part in a billion grams, of the DNA target13 .Saliva is a very useful DNA source due to the fact of being collected by painless and non-evasive way, able to be used even when it is stored in the most different conditions14. . However the molecular methods are a relatively newer techniques and need to be evaluated Different methods of identification applicable in forensic dentistry are available. However each one has its own limitations and this should be kept in mind while applying such techniques. It is necessary to broaden the pertinent studies of the theme, in order to establish protocols to allow additional tools in criminal investigation
- ↑ Mosby's Medical Dictionary, 8th edition. © 2009, Elsevier
- ↑ Venegas et al. Palatal Rugae: Systematic Analysis of its Shape and Dimensions for Use in Human Identification, Int. J. Morphol. 2009:7(3):819-825.
- ↑ Kapali S, Townsend G, Richards L, Parish T. Palatal rugae patterns in Australian aborigines and caucasians. Aust Dent J 1997;42:129-33.
- ↑ Thomas CJ, Kotze TW Jr. The palatal rugae pattern in six Southern African human populations. J Dent Assoc South Africa 1983;38:547-53.
- ↑ Alberta Kumar DA J Decay rates in a cold climate region: A review of cases involving advanced decomposition from the medical examiner's office in Edmonton. Forensic Sci 1998;43:57-61
- ↑ Utsuno H, Kanoh T, Tadokoro O, Inoue K. Preliminary study of post mortem identification using lip prints. Forensic Sci Int 2005;149:129- 32.
- ↑ Saraswathi TR, Mishra G, Ranganathan K. Study of lip prints. J Forensic Dent Sci 2009;1:28-31( citatation)
- ↑ Sivapathasundharam B, Prakash PA, Sivakumar G. Lip prints (cheiloscopy). Indian J Dent Res 2001;12:234-7.
- ↑ Strom F. Investigation of bite marks. J Dent Res 1963;42:312-6.
- ↑ Rothwell BR. Bite marks in forensic dentistry: A review of legal and scientific issues. J Am Dent Assoc 1995;126:223-32
- ↑ SA Sholl, Moody GH. Evaluation of dental radiographic identification: An experimental study. Forensic Sci Int 2001;115:165-9.
- ↑ Pötsch L, Meyer U, Rothschild S, Schneider PM, Rittner C. Application of DNA techniques for identification using human dental pulp as a source of DNA. Int J Leg Med. 1992; 105: 139- 43
- ↑ Sweet D, Lorente JA, Valenzuela A, Lorente M, Villanueva E. PCR-based DNA typing of saliva stains recovered from human skin. J Forensic Sci. 1997; 42:447-51
- ↑ Koh D, Ng DPK, Choo SGL, Ng V, Fu Q. Effect of storage conditions on the extraction of PCRquality genomic DNA from saliva. Clin Chim Acta. 2004; 343: 191-4.