ABSTRACT
Here in an attempt is made to relate culprit & victim precisely, exactly & perfectly so that a full proof case against the culprit can be prepared & the victim can be helped so as to get justice & culprit gets punished to the maximum.
A set of bite marks were made by victim on the hands of the culprit who was trying to sexually assault the victim later impressions of the victims oral cavity were made, models were prepared in dental stone & plaster of Paris, the models thereafter were articulated on the culprits bite-marks on the hand & thus the models were super-imposed & comparison was made so as to identify precisely & exactly the relation between the victim & the culprit.
INTRODUCTION
Odontology is the special science pertaining to the oral cavity and teeth and the relation of the same to Forensic Science while in functional aspect and otherwise so as to relate the same to the crime and criminal so as to get justice to the victim and thus help in judiciary and bring down the crime rate.
Odontology can be most helpful when in Sexual assault cases, child abuse assault cases, crimes against women and destitute and helpless people or the ingredients of the societies where no finance and so costly equipment are required for relating the culprit to the crime and victim thereby is needed.
The human race has two varieties of teeth in their life time and very rarely the third variety that is called as a) Primary, b) Secondary and very rarely the c) Tertiary.
a) Primary teeth also called as milk teeth or baby teeth comprise of in all 20 teeth with 10 of upper or Maxillary teeth of which 2 are central incisors, 2 are lateral incisors, 2 are the canines 2 are premolars or bicuspids and 2 are molars or grinders and similarly so are the mandibular teeth thus completing 20 teeth such that each quadrant of the jaw has 5 nos of teeth as follows: 1 Central, 1 Lateral, 1 Canine, 1 Premolar & 1 Grinder.
It is very important to note that there are hardly any variations seen in this numbers or the morphology or even placements of the teeth of this type and thus child has always a very exact and the fixed such types of teeth.
Anatomically if seen and observed the milk teeth have a root about the double size of the crown when just erupted and these teeth are to be well accommodated in a smaller jaws and hence they are of smaller sized too, except in case of the canines which have a root longer than the double the size of crown, thereby, giving it an uniqueness in characterization.
Morphologically if seen the incisors have more cutting edge and hence the Central incisors have nearly the double the cutting edge as compared to the Lateral incisors which are bit smaller and thus it can be seen that biting edge of around one and half of the Lateral incisor is equivalent to one Central incisor, whereas the Canines have hardly any either cutting edge or the grinding surface and so they are used more as for tearing of the food or any material and that is why they have longer roots too, thus giving them a very strong foundation and bone support.
Sometimes the roots go as long as three times as compared to the crown of the same tooth.
The premolars or bicuspids have more of the grinding surface and the molars have yet more nearly double the surface that of a premolar so that they are specialized teeth for grinding the food and the surface thereby increased by elevations of the teeth getting engaged into the depressions of the teeth thus while getting in action the teeth get engaged with each other perfectly well and in definite pattern such that the maxillary teeth get engaged to the outer side of the mandibular teeth as the maxillary as well as the mandibular teeth are in arch form and placed so as to form a parabola like curvature when the line drawn from the centre of each tooth like arch form.
The premolars of the milk teeth very nearly resemble the premolars of the permanent teeth and molars of the milk teeth very nearly resemble the first molar of the permanent teeth the only difference is the shape of the outline form of the placement that milk teeth will have a smaller arch form shape whereas the permanent teeth will have a bigger arch form shape as that will belong to an adult person.
In all the jaws of the mammals lower jaw being the mobile type with the joint responsible for the movement is termed as Temporo-mandibular joint, situated just in front of the tragus of the ear where the side locks of the hair just end and the same can be felt with fingers when the jaw is opened and closed while keeping the finger near the tragus of the ear both sides.
Except in case of the huge reptile the crocodile where the upper jaw is mobile since all mammals and man too has the lower jaw mobile the mandibular jaw is placed a bit inner side to the placement of the maxillary jaw and hence the closure of mouth is done or facilitated by the contraction action of the muscles of mastication viz. Massater, Medial Pterygoid and Temporalis which are very strong sets of muscles on either side of the jaws and never get disused atrophic even never used for months together whereas all the muscles of the body do get disused atrophy when not used due to sickness or accidents as in during immobilization!
However the opening of the mouth or the depression of the mandible is brought about by the contraction of the Lateral Pterygoid muscle the fourth pair muscles of mastication on either side of the jaws at the condoyle of the temporo-mandibular joint.
The muscle pulls the mandible so that the gravity action of the mass of the mandible dislodges it from the joint and brings it forward so as to cause the opening of the mouth.
The Permanent teeth comprise of 16 nos of teeth in each Maxilla and Mandible and are 8 teeth in each Quadrant such that there are 2 Central Incisors, 2 Lateral Incisors, 2 well grown up Canines, 2 first Premolars, 2 second Premolars, 2 first Molars, 3 second Molars and finally 2 third Molars or Wisdom teeth or the grinders or molars which have no virtually any relation to the wisdom of a person but it erupts when an individual is well grown up and has developed quite a bit of intelligence.
Like baby teeth the central as well as the lateral incisors have a more of a cutting edge more or less of the same proportion as discussed earlier as in baby teeth and the crown and the root ratio is also the same and the roots are generally of the double the size of the crown of the tooth and the anteriors have always a single roots and very rarely may be a bifid root or a small root attached to the main root.
Canines have a much longer root and may be extending to about at times 3 times the length of the crown and these have a bulky crown so as to be used for tearing of the food as well as leathery material and these comprises of a very strongest of the teeth and if healthy then can tear apart anything that comes in way! These also have a single root but at times due to genetic variation may attribute bifid or auxiliary roots.
First Premolar has a bit smaller size and shape as compared to the Second Premolar and also that the roots are single or laminated or bifid in case of the First Premolars but Second Premolars have two separate roots which may be fused at a length and may be curved or joined for entire length.
The First Molar has a nearly two times the bulk of the premolar and has three roots invariably and rarely there may be fusion of buccal roots to one root or laminated or bifid root but the palatal root is always separate and some amount of divergence is seen in their placements.
This tooth or grinder is also considered as a key tooth as it is this tooth that first erupts and then the milk teeth or the baby teeth start falling in sequence and the newer or the permanent teeth start erupting chronologically as per their completion of crown formation and the formation of the roots starts that pushes the tooth to the mouth and thus eruption starts.
And also it is true of the Second Molars when the crown is little smaller in size as compared to the first molar and also it is placed slightly outwards on the cheek side and has two roots or three even as the first molar and even has a variation of all the roots fused together or divergent rarely.
The Third Molars are however more placed on the cheek side out of the arch and at times not even meeting the opposite teeth or antagonists due to such placements and may be biting cheek while eating and thus causing trauma and injury to the cheek.
The mandibular teeth are the ones which receive wear and tear on the outer side whereas the maxillary teeth always receive wear and tear on the inner side as a result of the outer side of the placement to the mandibular teeth.
The opening of the mouth is about 3 to 4 fingers wide (the distance between the two Central Incisors of Maxillary and Mandibular teeth) of an individual such that the teeth upto premolars as in case of an adult and upto first molars in case of a child can be used by an individual while biting and the conditions like Angular chelosis, Sub Mucous Fibrosis, cuts on lips, injuries to jaws/teeth may restrict the opening of the mouth thereby reduction of bite marks of an individual and the doubtful co relation to victim and culprit.
The jaws when open form an angle between the Dental arches that reduces the space as we go inner side and hence the grinders or the molars are never utilized while biting action and hence they cannot be exhibited on the actual biting but these can be recorded so as to show the continuity of the dental arch.
The carnivorous animals have the teeth with more of the biting and tearing edge with all of the teeth and they are more of the pointed edges on the teeth surface whereas the herbivorous animals have the teeth with more of chewing surfaces as a result their teeth have more of grinding surfaces and their teeth are flat surfaced too like stumps and there are spacing too in all the teeth of the carnivorous as well as herbivorous animals.
And there is absence of Amylase enzyme too in the saliva of the animals.
Both the varieties of these animals have the tongue texture with lot of sharp scales and hence giving horny or very rough surface texture as compared to a human tongue that has very smooth and velvet like surface texture.
The bite marks can be observed on a surface bitten only up to maximum of the second bicuspids' extent and the reason for this is that while doing the biting action the Central incisors contact each other with the antagonists of the other jaw and this results in to a space between the bicuspids and the molars and is known as the curve of Spee or the angle of Spee.
The second incisors or the lateral incisors meet at little distance away as compared to the Central incisors and the Canines meet at very closely as the Central incisors do and later the bicuspids meet at a little less leaving the distance between the two sets of the teeth representing the curve of Spee and the curve of Spee further increases such that molars and the third molars do not meet each other while in biting action and all the teeth meet each other only when in Centric occlusion or while chewing action is in progress.
Hence the bite records can match the teeth of the culprit or a victim or the recorded models even only up to the limitations of the second bicuspids or very rarely even the molars can show the evidences.
Bite marks offer clue in woman's murder
LUCKNOW: The bite marks on 60-year-old woman who was found dead at her Papermill colony residence on March 20 could lead the police to the killer. In a new trend, the police have sought the help of a forensic Odontologist (a dentist who assists in criminal investigation) to crack the case.
According to a forensic Odontologist, the bite marks could be that of a woman. This points towards the possibility that a woman was involved in the murder.
Anita Sharma, wife of Late SK Sharma, a resident of B-2/3, Papermill Colony, was found strangulated at her home. The door of the house was ajar. Anita was found dead on the floor of the house.
Anita's postmortem report had confirmed two bite marks on her hands. After getting the autopsy report, ASP Aliganj Anees Ahmed Ansari sought the help of Dr Vikram Ahuja, chief dentist at Shushrut Institute of Plastic Surgery (SIPS).
Dr Ahuja confirmed to TOI that the bite marks in all probability are that of a woman. Dr Ahuja, who took training in forensic odontology from Cardiff University, UK, lifted the two bite marks from Anita's body and collected all minor details. Since the marks were lifted after postmortem, the accuracy of the result would be over 70% he said. If the marks had been taken before autopsy, the accuracy would have been 100%, he added.
Detailing about the science, Dr Ahuja said human teeth leave prominent marks. In the flesh, they leave noticeable bruises or puncture marks. The distinctiveness of the bite mark is used for the identification of the person. For example, gaps or abnormalities present in the teeth of a suspect are compared with the bite mark to see whether it is logical to say that the suspect's teeth made the bite mark or not, Dr Ahuja added.
Every detail of the bite mark, like color, size, appearance, location and number of times the victim was bitten are recorded. Photos of the bite marks and samples are taken. Based on these impressions, a dental mold is made and a profile of the criminal is drawn, said Dr Ahuja, adding that if a suspect has been arrested, their dental records are taken and compared to the bite marks for verification.
To be able to match a suspect with a bite mark, the mark is documented using photographs, said Dr Ahuja. Then a record of the suspect's teeth is acquired where odontologists take an impression of the teeth in silicon rubber. The impression is set using plaster to make a replica of the gums and teeth and compared with the samples. These photos and replicas are then compared with the crime scene bite mark, he further said.
Meanwhile, ASP Aliganj told TOI that bite marks found on Anita's body were matched with three suspects. One suspect has been ruled out by Dr Ahuja, but the other remains under scanner, he added.
Reference : - http://articles.timesofindia.indiatimes.com/2012-04-03/lucknow/31280811_1_marks-gums-and-teeth-impression (Last Accessed on 12th December 2012)
METHODOLOGY
A female of aged 16 years here after called as victim, was asked to bite on the fore-arm of a man aged 60 years here after referred to as a perpetrator & in doing so the bite marks were generated on the fore-arm.
The above situation was created such that it appeared as assault took place.
The bite-marks were recorded by taking their photographs.
In the photograph indentations of teeth was clearly visible on the fore-arm of the culprit.
The upper & lower jaw impressions of the victim were made by mixing Alginate impression material with water in a bowl & then loading the material in dental perforated impression trays.
On setting of the impression material the impression trays were removed from the mouth, washed & wetted with water & left for further procedure.
In another rubber bowl dental stone was mixed with water in proper proportion so as to get creamy flowing homogenous mass which with the help of plaster spatula was poured in the impression taken & plaster was allowed to flow in the final cavities & negative records of jaw arches created by making impression.
Methodology
The dental stone, supported by base of plaster of Paris was allowed to set for about 60 to 70 minutes & later on confirming complete setting of the same by filling the warmth of the models, the same were separated from the impression material by tapping so as to get exact positive identical replica of dental arches & surrounding tissues.
The distance between the 2nd premolar of right side to that of left side of each upper and lower arch was measured by the scale in centimeters, and also the perpendicular distance to mesial diastima on this inter premolar line was measured and also compared to with the bite marks of the victim’s model and the culprit’s actual bite marks and this very exactly matched with each other whereas those models considered for comparison of the same age group with three other individuals never matched so perfectly!
COMPARISION
The dental arch models thus received were positive record of the dental arches of the victim & when these were held & super imposed with the bite marks generated on the fore-arm of the culprit.
The bite marks
received on the fore arm of the culprit was also compared with those of other
three sets of Dental models of the persons of the same age group and was seen
that these last three models did not superimpose vividly exactly due to placements
of teeth, different arch forms, and absence of certain teeth.
RESULT & DISCUSSION
The dental arch models of the victim & the teeth setup exactly matched with that of the bite-marks of the fore-arm of the culprit.
Thus the bite marks given by the victim to the culprit exactly & very precisely match with each other unless the culprit or suspect is nabbed after lapse of very long time or the culprit or suspect receives medical help in the mean time he gets before being nabbed.
CONCLUSION
Thus with the help of models generated by taking impressions of the dental arches of the victim we can compare the bite marks generated on the body parts of the culprit & the presence of culprit is exactly precisely & specifically confirmed with that of victim while the crime is being committed & victim can get justice by requesting maximum punishment to the culprit.
The preparation
of the database of the bite marks will not serve the purpose as the victim’s
bite marks on already nabbed suspect’s forearm are to be
compared with and the presence of the culprit is to be confirmed while the
crime is being committed. The database only will be useful when there are so
many bite marks recorded and the marks are to be compared with that of the
culprit when the suspect has biting tendency and bitten so many people around thus
committing to crime.
ACKNOWLEDGEMENTS
I hereby acknowledge the help rendered to me in completing this presentation & I am thankful to the following people for their support.
1. Voomivarada Panchal
2. Anoop Kumar Srivastava
3. Srikant Sethi
4. Madhavi Nevalkar
Above research paper was presented & accepted in DNA international Forensic Conference 2012 at Hyderabad on 16th December 2012. It was also presented at the Indian Dental Conference at Science city Kolkata 2013.
By Dr. Pramathesh Panchal
Mumbai India.
Mumbai India.
E-Mail: - pramatheshpanchal@gmail.com
Mobile: 091 9833411181.
Mobile: 091 9833411181.
