| Abstract|| |
Objectives: The study was conducted to emphasize the sensitivity and specificity of dental pulp in identifying the ABO Blood group, Rhesus factor and also to emphasize the role of dental pulp in forensic odontology to identify the deceased individual.
Materials and Methods: The study was conducted on 60 patients. The samples obtained from finger-prick method from those 60 patients were considered as control and the samples obtained from the pulp were considered as case. The blood grouping, Rhesus typing for capillary blood drawn by finger prick was done by slide-agglutination method and the blood grouping, Rhesus typing for extracted dental pulp was done by absorption-elution method.
Results: Fifty seven teeth out of sixty showed positive results. Blood group elicited from capillary blood done by slide-agglutination method matched with that of the pulpal blood group elicited by absorption-elution method. Three showed negative results.
Conclusion: As the teeth are the hardest, most stable biological material, resist adverse environmental conditions and the pulpal tissue inside the teeth is well protected, the blood group antigen from pulp remains stable for long. Thus, the high potential value of dental pulp tissue is highlighted in this study.
Keywords: Capillary blood group, forensic odontology, pulpal blood group, Rhesus factor
|How to cite this article:|
Aswath N, Selvamuthukumar S C, Karthika B. Role of dental pulp in identification of the deceased individual by establishing ABO blood grouping and Rhesus factor. Indian J Dent Res 2012;23:811-3
Forensic identification by its nature is a multi-disciplinary approach relying on positive identification methodology. , This branch dealing with the identification of the deceased has many maxims, the best known of which, is that every contact leaves its trace. , Dr. Oscar Amoedo is regarded as the father of forensic odontology.  Federation Dentaire Internationale defines forensic odontology as "that branch of dentistry which, in the interest of justice, deals with the proper handling and examination of dental evidence, and the proper evaluation and presentation of dental findings." 
|How to cite this URL:|
Aswath N, Selvamuthukumar S C, Karthika B. Role of dental pulp in identification of the deceased individual by establishing ABO blood grouping and Rhesus factor. Indian J Dent Res [serial online] 2012 [cited 2017 Nov 24];23:811-3. Available from: http://www.ijdr.in/text.asp?2012/23/6/811/111268
Teeth are invaluable sources of personal identification in mass disasters.  Pulpal tissue is one of the most protected oral tissue being surrounded from all sides by the dental hard tissues, so it was decided to use the dental pulp for detection of ABO blood grouping and Rhesus factor.  Since tooth pulp contains lot of blood vessels, blood group antigens are most certainly bound to be present in tooth pulp. 
| Materials and Methods|| |
The study was conducted on 60 patients who reported to the Out-patient Department of Oral Medicine and Radiology, Sree Balaji Dental College and Hospital, Chennai for seeking dental treatment. Sixty teeth were collected from patients, with age ranging from 13 years to 65 years, who underwent extraction of teeth due to poor periodontal status and for the purpose of orthodontic treatment. Capillary blood samples obtained from finger prick method from those 60 patients were considered as control and the samples obtained from the dental pulp were considered as case.
Permission from the Institutional Ethical Committee of Sree Balaji Dental College and Hospital, informed consent from patients to participate in the study was obtained. The blood grouping and Rhesus typing were performed in the capillary blood drawn by finger prick method by slide agglutination and in the extracted dental pulp by absorption elution method in the clinical lab.
In slide agglutination method, capillary blood was withdrawn by a prick with a lancet on patient's finger. A drop of blood was placed on three glass slides over which anti-serum A, B, D were added respectively, mixed and observed for agglutination.
In absorption elution method, dried pulpal content was scooped using spoon excavator and placed into three test tubes. To each of these test tubes three drops of antiserum A, B, and D were added and allowed to be soaked sufficiently with antiserum for 2½ h at room temperature for the antibodies to combine with their specific antigens. After removing antiserum, each sample was washed three times with cold saline solution (it was centrifuged and the supernatant was sucked with pipette) to remove the non-reacted serum. Then two drops fresh saline was added to the sample and the test tubes were heated in a water bath at 56°C for 10 min to elute the antibodies. A drop of 0.5% A or B group red cell suspension was immediately placed into each respective test tube to combine the eluted antibodies with known red blood cells. This results in agglutination of respective antibodies to the group antigen present in the cell surface of red cells. Then incubated at 37°C for 30 min to enhance agglutination, and after this procedure, it was centrifuged at 1500-2000 rpm for 1 min for flocculation formation. By gentle shaking of the test tube the presence or absence of red cell agglutination was ascertained with microscope at magnification of × 100. In this study, attempt was made to identify blood group and Rhesus factor from the pulpal tissues. The pulpal blood group was matched with that of the capillary blood group.
| Results and Discussion|| |
Among the 60 samples considered in this study, 30 were males and 30 were females, whose age group ranged between 13 years and 65 years. 57 teeth out of 60 showed positive results that is, pulpal blood group matched with that of the capillary blood group elicited by the slide agglutination method and three showed negative results. Results were statistically analyzed using Non-parametric test- Wilcoxon signed rank test and the P value of 0.083 [Table 1] was obtained.
|Table 1: Comparison of agglutination on slide agglutination method and absorption elution method|
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In [Table 2] among 30 males two showed negative results and the P value is 0.157. Among 30 females one showed negative result and the P value is 0.317. Among 60 patients, eleven patients were in age range between 13 years and 25 years and all showed positive results with P value 1.000. Twenty four patients were in the age range between 26 years and 45 years and all showed positive results with P value 1.000. Remaining twenty five patients were in the age range between 46 years and 65 years and in that 23 showed positive results and three showed negative results with P value of 0.083. Among 60 samples, 19 were AB positive, 3 were A positive, 14 were B positive, 1 was B negative, 21 were O positive and 2 were O negative. Among 19 AB positive blood group three showed negative results and the P value was 0.083. All the three A positive blood group showed positive results and the P value was 1.000. All the fourteen B positive blood group showed positive results and the P value was 1.000. One B negative blood group was insufficient to derive the P value. All twenty one O positive blood groups showed positive results and the P value was 1.000. Both O negative blood groups showed positive results and the P value was 1.000.
Wilcoxon Signed Rank Test indicates that there was no significant difference in the blood groupings between two methods: Finger prick and pulpal method. It was assumed that there is no difference in the blood groupings between two methods used to find out different groups. The assumption of no difference in null hypothesis was formulated for the present research and this hypothesis was tested by using Wilcoxon Signed Rank test since the samples are not different but are related to one another. Null hypothesis has to be rejected, if P value of the test statistic is < 0.05. In the present study P value of 0.083 (P = 0.083 was > 0.05) was obtained, it can be inferred that capillary blood group obtained by slide agglutination method and pulpal blood group obtained by absorption elution method are the same.
The negative results in three samples could be attributed to insufficient quantity of pulp, reduction in fibrosed tissue in the pulp with increasing age and also increased calcification of the canal. ,, In living people, a large number of aerobic gram-negative bacteria are present in saliva or on dental tissues. , Together with yeasts, the aerobic gram-negative bacteria tend to grow explosively in contaminated stored specimens or putrefying material and tend to overgrow the other species. , The massive growth of such bacteria tends to obscure the pulpal blood group antigen and it can produce a negative result. , Negative results can occur from the specimen of post-mortem dental pulp due to haemolytic erythrocytes, and putrefaction, mummification or skeletonization of the body during post-mortem interval. ,
This study finding is consistent with the study done by Yumi Nakayama and Yasuhiro Aoki  in 1998. In this study, 30 teeth were subjected for the study. The blood types determined using the gauze specimens and the results obtained from the pulps matched in 27 cases. Amongst the remaining three samples of which the blood group could not be confirmed, two were from old patients aged 66-71 years, and one was markedly worn out.
| Conclusion|| |
In this Case Control Study among 60 samples, 57 samples pulpal blood group matched with that of the blood group determined by Slide agglutination. Three negative results were obtained only in older age group because of regressive changes of pulp. As the teeth are the hardest, most stable biological material, resist adverse environmental conditions and the pulpal tissue inside the teeth is well protected, the blood group antigen from pulp remains stable for long. ,, Thus, the high potential value of dental pulp tissue is highlighted in this study. This study has to be continued on a larger sample.
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Department of Oral Medicine and Radiology, Sree Balaji Dental College and Hospital, Narayanapuram, Velachery Main Road, Chennai, Tamil Nadu
Source of Support: None, Conflict of Interest: None
[Table 1], [Table 2]