Knowledge, Awareness, and Practice of Forensic Odontology Among Dental Surgeons: A Cross-Sectional Study

Introduction

Forensic odontology, also known as forensic dentistry was defined by Keiser-Nielson in 1970 as “the forensic medicine branch in which the interest of justice deals with proper handling and examination of the dental evidence and with proper evaluation and presentation of the dental findings”.¹ Forensic dentistry is used in the therapeutic and the diagnostic examination and evaluation of injuries to teeth, jaws, and soft tissue in the oral cavity; in the identification of individuals in the casualties in mass disasters and the identification, examination, and evaluation of bite marks which can be seen in child abuse cases and sexual assaults.

The whole branch of forensic odontology relies on sound knowledge and interpretation of the teeth and the jaw, which is possessed by the dentist. The theory behind forensic dentistry is that there are no two mouths alike even if they are identical twins. Teeth can leave marks on the surface of the skin or any medium. Since many individuals visit a dentist, their dental records can be easily accessed and compared with the suspect’s teeth.²

Dental identification is based on the systemic comparison of pre- and post-mortem dental features of an individual based on their dental records and the supporting radiographs. But this technique is complicated by inadequate ante-mortem dental information due to the lack of a centralized survey system to store the information and the lack of knowledge among general practitioners about the identification and collection of the evidence.³

Dental records are created and maintained to contribute to the safety and continuity of dental care, for treatment decisions, legal purposes, and treatment planning. The present cross-sectional study is an effort to evaluate the knowledge, attitude, and practices of the general dentist in urban localities of Bengaluru, India.

Methodology

This cross-sectional study was conducted by designing the questionnaire with close-ended questions. General practitioners with both undergraduate and post-graduate training other than oral pathology in the potential urban localities of Bengaluru practicing for at least five years were included in the study. Ethical approval from the Institutional Ethical Committee approval was obtained.

The sample size was calculated from the previous study and non-respondents were taken into consideration, thus sample size was rounded off to 240. The study included 240 practitioners from the potential localities of Bengaluru like Hebbal, Yelahanaka, J. P. Nagar, Jayanagar, K. R. Puram, Koramangala, Basaveshvaranagara, and Rajajinagara due to the high presence of the dental clinics in these areas. Thirty general dental practitioners from each locality were randomly selected using computer-generated random numbers for the survey and the data was selected based on purposive sampling.

The offline questionnaire included 15 variables, which included all the three components like knowledge, attitude, and practices with close-ended questions (Table 1).

SPSS 17 version was used for statistical analysis. Descriptive statistical analyses were used to report frequency and percentage.

Results

Results showed that 89% of practitioners believed that forensic odontology is an important aspect of dentistry. 11% were not sure of this branch’s importance and applications. 95% of the practitioners agreed on the importance of maintaining dental records to identify crime suspects but only 27% of the practitioners maintained dental records. 87% of general dental practitioners agreed that the estimated age by observing the chronological tooth eruptions and the density of the adjoining bone on a radiograph. While 8% said that they estimated the chronological age by considering even general wear and tear of the tooth. 5% were not sure how to identify age. While 93% of the practitioners had a general idea that the dimension of teeth in females was smaller as compared to males they didn’t have any sound scientific backing.

32% of dental practitioners could recognize child abuse by dental or medical examination, 63% by questioning the parents or child, and the rest 5% had no idea. 88% of the dentists had the awareness to differentiate between bite marks contusions, lacerations, and incisions. 12% found it difficult to differentiate bite mark findings. Among the participants, 92% of practitioners agreed that the role of photographs is crucial in forensic odontology, and only 8% used photographs to record cases of abuse.

92% of practitioners were also of the opinion that present knowledge regarding the forensic odontology branch was inadequate. 97% of dental practitioners believed that they have not received any formal education to record dental evidence in medico-legal cases. 75% of the practitioners believed that their knowledge in forensic odontology could be enhanced by attending, Continuing Dental Education (CDE) programs and workshops. 25% felt that reading journals could enhance knowledge in forensic odontology.

Discussion

From AD-66 to date, dental identification has proved vital in identifying deceased individuals. In the year 1849, a law based on forensic odontological findings accepted the first case.² The branch of forensic science refers to the area of work that can be utilized in a judicial setting and then accepted by the court and general scientific committee to separate the truth from the untruth.³ General dental practitioners play an important role in helping the law to take its due course in bringing the culprits to justice. The present survey was able to bring out the deficiency among dental practitioners in Bengaluru regarding the maintenance of the dental records, observation skills in recognizing signs for cases of abuse, and also in recording the found observation.

Maintenance of dental record

Only 27% of the practitioners answered in the affirmative that they maintain dental records, although 95% of the practitioners agreed on the importance of maintaining dental records. On verbal inquiry about why the records are not maintained many practitioners believed that:

• It was time-consuming and expensive and they don’t get adequate remuneration
• The patients themselves feel it is not that important. Window shopping by patients has discouraged many dentists to record dental findings.
• There is no centralized unit to record and store the findings of the dental practitioners making the entire recording exercise futile.

Clinical techniques for age estimation

87% of general dental practitioners who participated in this survey were able to identify age by observing chronological tooth eruption and density of adjoining bone on a radiograph and 8% said that they also looked into other criteria while estimating the chronological age.

Erbudak HO et al. has suggested that age estimation plays an important role in forensic dentistry for dead individual identification as well as for alive people to clarify criminal and civil liability issues.⁴ The teeth, skeleton, or bone structures can be used for the estimation of age as the indicators for maturity. The teeth maturation process offers a valuable index of dental age and it serves as a better index of maturation than the other indices.⁵ Teeth maturation can be divided into initial mineralization, crown formation, root growth, eruption of the tooth into the mouth, and root apex maturation.⁶

Tooth eruption, attrition, tooth calcification, secondary dentin deposition, periodontal diseases, cementum apposition, root translucency, color changes, root resorption, and the increase in root roughness are the dental changes related to age which can be observed in radiographs as different types of the dental age estimation methods.^4-10

In 1960, Nolla created a new kind of 0–10 graded scale for the development of each tooth which was based on the calcification of the teeth for estimation of dental age. This method was considered more accurate when compared to the other methods used in Indian children.⁶

Gustafson (Gustafson methods: 1947, 1950, and 1955) method attributed to the periodontal recession, secondary dentin formation, apical translucency, attrition, external root resorption, and cementum apposition as the dental variations related to chronological age.¹¹ The regression equation calculations are used for the age estimation although the applicability of this method is limited by the quality of X-ray images obtained.¹¹ Among dental changes in the root dentin translucency was considered as the best parameter for the estimation of age.⁹ Furthermore, the calculation of age using a total score was found to be more accurate than the calculation of age using a score of a single physiological factor.¹²

Sex determination methods

93% of the practitioners in the present survey thought that the dimension of teeth in females was smaller compared to males but they didn’t have any sound scientific backing.

Shafer et al. has used buccolingual and mesiodistal dimensions of the teeth for sex differentiation.¹³ Studies have shown significant differences in crown dimensions of male and female teeth; mandibular canines show the greatest dimensional difference with large teeth in males than in females.¹⁴

A study done by Anderson and Thompson in 1973 showed that the width of mandibular canine and intercanine distance were greater in males than in females and permitted accurate differentiation between the sexes in 74% of cases.¹⁵

Distal accessory ridge, which is a non-metric characteristic on canines is considered the most sexually dimorphic trait of the crown in human dentition, with males showing higher frequencies and more pronounced expression than females.¹⁶

The mandibular canine index which was proposed by Rao and his associates had given an accurate sex indication in an Indian population using the mesiodistal (m-d) dimension of mandibular canines.¹⁷

These researchers explained the formula as:

[(Mean m-d canine dimension) + (Mean m-d canine dimension in females + S.D)] / 2

The values attained using this formula are 1mm as the maximum possible mesiodistal dimension (m-d) of the mandibular canines in females. The same dimension is greater in males than in females. The success rate of determining the sex using the above-given formula was as close to 89%.¹⁵

Bite mark recognition and analysis

The question in the survey regarding child abuse and bite mark brought about a contrasting result. Though 88% of the practitioners in the survey were able to differentiate bite mark injuries, only 32% of practitioners were able to identify that bite marks are a result of abuse.

Child maltreatment varies widely in degree of severity. Dorion stated that the abuse of children needs to be listed among the human activities related to the evidence of bite marks.¹⁸ In New York City, almost 20% of the children requiring autopsies exhibited bite marks inflicted before death.¹⁹

Beckstead et al.²⁰ stated that “A bite mark is registration of the tooth cutting edges on a substance inflicted by the closure of jaw. The severity of the bite mark depends on the magnitude and the duration of the bite, the tissue involved, and the degree of injury.”

The marks left by the teeth in the lower arch are more circumscribed while those of the upper arch are more diffused. This kind of disparity can be explained as maxillary teeth are used for holding purposes, while the mandibular teeth transfer biting force and are thus used for cutting or incising. A suck mark occurs when skin is drawn forcefully into the mouth and held, resulting in a bruise or hemorrhagic area in the center of the bite mark. A thrust mark further compounds a suck mark which occurs when the tongue is pushed against the lingual aspect of teeth with the skin between the two. The presence of either type of these mark suggests sexual abuse.^{21, 22}

A typical bite mark is a circular or oval configuration of bruising or ecchymosis, which upon closer examination may represent both the arch form and individual teeth. In such instances, a hemorrhagic area representing a thrust or suck mark may be seen between markings left by teeth.²³

On discovering a bite mark injury, one should always consider the possibility of self-infliction either intentional or accidental. Accidents during sports and seizures often result in self-inflicted accidental bite marks. Self-inflicted intentional bite marks can occur when a victim places or is forced to place body parts into his or her mouth during an assault or merely to unjustly incriminate another person¹⁸.

The American Board of Forensic Odontology (ABFO) realized the need to standardize the collection of evidence of bite marks and, in 1984, published its guidelines for bite mark analysis. The publication and subsequent use of these guidelines by those involved in forensic dentistry have enhanced both the acceptance and effectiveness of bite mark evidence.²⁴

Questioning the victim regarding the cause of the injury should follow bite mark evidence; this may help in establishing the actual cause of the injury.

Use of Photography in Dentistry

Though 92% of the practitioners who took part in the study agreed that the photographs are an important adjunct to recording the findings while examining cases of abuse; only 8% used photography for the same.

If the existing light is being used to capture an image, the shutter speed selected must always be greater than 1/lense focal length. This rule ensures that the image is not blurred by shaking the camera. It may be necessary to photographically capture the injuries digitally or with film, in color and in black and white using visible as well as nonvisible light. The injury may also vary in appearance in the photographs of each of these incident light sources and over time if photographed serially.²⁴ For bite mark photography, larger the image file size, less pixilation (blurring) when enlarging to life-size proportions.^25,26

Knowledge enhancement in forensic science

In the present survey, 92% of practitioners believed that the current knowledge about forensic odontology was inadequate. An equally high percentage of dental practitioners also had the opinion that they have not received any formal education to record dental evidence in medico-legal cases. Participating in programs and workshops as well as reading journals on forensic science about dental findings can be a possible solution to enhance the knowledge of forensic odontology.^27-29

In life sciences, both the discovery-based research courses and the journal clubs can achieve many of these learning goals with the undergraduates, even though each has noteworthy limitations.^30,31 The hands-on research classes are proven to be an effective entry point for the training of new students in the process of scientific discovery, except for the bioinformatics related classes.³¹

The American Medical Association’s evidence-based medicine working group has proposed a new fourstep method in evidence-based medicine (EBM) for physicians to stay abreast of technical progress.^{32, 33} This method consists of

• Posing a clinical question;
• Searching for the best available evidence using published scientific work; 
• Critically appraising the information found;
• Applying relevant information to solve the clinical problem.

In a study by Nieri M et al.,³⁴ a question was asked to the dental practitioners to assess the effectiveness of various continuing education tools in delivering updates in therapy. Clinical training obtained the highest score, thereby supporting the position that clinical skills can be improved with specific feedback as shown by many studies.^35-38 Internet obtained the lowest score probably because this tool does not yet constitute a valid learning instrument for dentists either for learning new techniques or for gathering important scientific information in therapy.³⁹

The traditional tools for obtaining continuing education like clinical training, articles, oral presentations, and books seem to be preferred over the more innovative tools such as videos and the Internet by dental practitioners.^{40, 41} One must note that the sources rated most important in theory are not necessarily the most used in practice.⁴²

Conclusion

In the contemporary world of forensic investigations, a dental practitioner must be knowledgeable and technically sound to estimate age and sex and in identifying and differentiating bite marks. A dental practitioner should also consider his importance in the forensic science field by maintaining a dental record, which might be of paramount help in medico-legal cases. The dental records should be created and maintained properly to contribute towards the safety and steadiness of dental care, treatment planning, treatment decisions, and legal purposes. Priority must be put on increasing the knowledge of forensic odontology by including better curriculums for the undergraduates’ training.

Acknowledgement

None

Conflict of Interest

None