|FORENSIC ODONTOLOGY: ORIGINAL ARTICLE
|Year : 2021 | Volume
| Issue : 3 | Page : 314-320
Comparison of two methods in estimating the relation between dental age and chronological age
Surya Gunasekaran1, Nazargi Mahabob2, Captain S Elangovan1, Suman Jaishankar1, B Senthil Kumar1, Deepika Rajendran3
1 Department of Oral Medicine and Radiology, KSR Institute of Dental Science and Research, Tiruchengode, Tamil Nadu, India
2 Department of Oral Maxillofacial Surgery and Diagnostic Sciences, King Faisal University, College of Dentistry, Al Hasa, KSA, KSAKSA
3 Department of Oral Medicine and Radiology, Saveetha Dental College, Chennai, Tamil Nadu, India
|Date of Submission||08-Apr-2021|
|Date of Decision||21-Jun-2021|
|Date of Acceptance||05-Aug-2021|
|Date of Web Publication||28-Sep-2021|
Dr. Surya Gunasekaran
Department of Oral Medicine and Radiology, KSR Institute of Dental Science and Research, Tiruchengode, Tamil Nadu
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Introduction: Personal identification is becoming increasingly important not only in legal medicine but also in criminal investigation, identification, and genetic research. Dental age (DA) estimation has gained acceptance because it is less variable when compared to other age indicators. Aim: This study aims to determine DA by radiographic methods in digital orthopantamogram using Willem's method and in intraoral periapical radiograph using Kvaal's method and also to find out the accuracy of two methods in determining the relation between DA and chronological age. Materials and Methods: The study sample consisted of 75 randomly selected subjects who referred to the Oral Medicine and Radiology department for the purpose to undergo orthodontic treatment, were selected. Orthopantmograph and one intraoral periapical radiograph of right mandibular first molar using paralleling cone technique were taken for each patient The DA was determined using orthopantamography by Willem's method and intraoral periapical radiograph by Kvaal's method. Results: The student's t-test was used to analyze the significance between the two different age estimation methods. In Demirjian's method, the overall mean difference between estimated DA and CA for males was 15.10 years, while for females was 11.88 years. Estimated DA assessment by Willem's method appeared to underestimate chronological age both in males and females. Conclusion: In this study, a significant relation was found between estimated DA and CA in the Willem method (p-0.00) and Kvaal's method (p-0.05). Both the methods seem to be applicable in estimating the age of both genders.
Keywords: Chronological age, dental age, intra-oral periapical radiograph, orthopantmograph
|How to cite this article:|
Gunasekaran S, Mahabob N, Elangovan CS, Jaishankar S, Kumar B S, Rajendran D. Comparison of two methods in estimating the relation between dental age and chronological age. J Indian Acad Oral Med Radiol 2021;33:314-20
|How to cite this URL:|
Gunasekaran S, Mahabob N, Elangovan CS, Jaishankar S, Kumar B S, Rajendran D. Comparison of two methods in estimating the relation between dental age and chronological age. J Indian Acad Oral Med Radiol [serial online] 2021 [cited 2021 Nov 29];33:314-20. Available from: https://www.jiaomr.in/text.asp?2021/33/3/314/326888
| Introduction|| |
Personal identification is becoming increasingly important not only in legal medicine but also in criminal investigation, identification, and genetic research. It is an important basis for differentiating guilty from innocent in legal issues, for ethical issues and for declaration of death reports, and the basis for probing into criminal cases, mass disaster or war victims.
The mouth has been identified as the organ system “where it all begins.” Forensic odontology, or forensic dentistry, as defined by Keiser-Neilson in 1970 as “a branch of forensic medicine which in the interest of justice deals with the proper handling and examination of dental evidence and with the proper evaluation and presentation of the dental findings.”
Dr. Oscar Amoedo was considered the father of the forensic odontologist. The thesis was done by him entitled 'L' Art Dentaire en Medicine Leagale' to the faculty of medicine. This book is the first comprehensive text on forensic odontology.
The traditional methods of personal identification include anthropometry, fingerprints, sex determination, estimation of age, measurement of height, identification of a specific individual, and differentiation by blood groups. The accurate estimation of age at the time of death with the help of dental remains is an important parameter for identification.
Age plays an important role in various fields, such as forensic science, various social and legal settings, and treatment planning in clinical dentistry. The age of a person can be determined by the degree of maturation of the different tissue systems of an individual.
Literature reports different morphological and radiological techniques for age assessment. Dental age (DA) estimation has gained acceptance because it is less variable when compared to other skeletal and sexual maturity indicators. Teeth form a unique part of the human body, as they are the most durable and resilient part of the skeleton. At times teeth are the only means of identification when the dead bodies have changed so extensively that external characteristics yield little information.
DA determination is important because it is a useful tool to estimate the Chronological age (CA) of a child with an unknown birth date. Teeth are among the most reliable tools in the process of identification of age, especially in the first and second decades. Radiological methods are based on the evaluation of tooth development on the various radiographic images as intraoral periapical, panoramic radiographs, digital, and advanced imaging technologies to assess the extent of tooth mineralization from the moment when radiopaque spots become visible before tooth calcification until the tooth apex is closed. The stages of development can be considered as one of the most dependable indicators in assessing the age of the victim.
Dental evidence was first accepted by law in the USA in the Webster-Parkman case in 1849. Olze et al. in 2005 reviewed the various methods of staging and found that the Demirjian classification achieved the highest values for both observer agreement and for correlation between the stages as defined by the method and true age. Therefore Olze et al. regarded Demirjian's system to be the best for DA estimation. However, modified Demirjian's method proposed by Willem has been tested in various geographic population groups and has shown higher accuracy than Demirjian's method age estimation. The accuracy of Willem's method can be contributed to its single step calculation from the gender-specific chart.
Aims and objectives
To determine DA by radiographic methods in digital orthopantamogram using Willem's method and in Intraoral periapical radiograph using Kvaal's method.
To find out the accuracy of two methods in determining the relation between DA and chronological age.
| Materials and Methods|| |
- Above the age of 8 years
- Only fully erupted mandibular first molar in normal functional occlusion
- Those who give voluntary consent for the study procedure
- Absence of systemic diseases, dental anomalies, nutritional and endocrine problems, premature birth, and birth defect.
- Teeth with radioopaque fillings
- Any associated pathologies
- Malalignment, rotation
- Impacted teeth
- Teeth with developmental anomalies.
The study protocol was approved by KSR Institutional Ethical Committee Ref. no. 107/KSRIDSR/EC/2015 dated 21.12.2015 following the Declaration of Helsinki ethical principles for medical research involving human subjects. Written informed consent was obtained before the investigatory procedure. Patients who were referred to the Oral Medicine and Radiology department for the purpose to undergo orthodontic treatment were selected randomly for the study. Orthopantmographs were taken for orthodontic treatment purpose and one intraoral periapical radiograph with right mandibular first molar by using paralleling cone technique were taken for the same patient for this study purpose. The sample size is one of the criteria for generalizing the results obtained by the applicability of any dental age (DA) estimation method to a specific population. The sample size of the subjects calculated by conducting a pilot study was 75.
Sample size estimation
The pilot study was conducted in the Department of Oral Medicine and Radiology. Sample size was estimated using the parameters obtained from the pilot study. The sample size (n) is calculated according to the formula:
n = [Zα × (SD)/d]2
n = Sample size
Zα = Corresponding degree of Confidence interval
SD (σ) = Standard deviation from pilot study
d = Accepted error (0.5)
n = [Zα × (SD)/d]2 = [1.96 × 2.15/0.5]2 = 71.0016
To round off, It was estimated as 75
The study sample consisted of 75 randomly selected subjects (males and females) of age ranging from 7 to 32 years divided into five groups according to age. Clinical examination of all 75 individuals was performed and the name, sex, and date of birth of each individual and date of radiography were recorded. CA of an individual was calculated by subtracting the birth date from the date on which the radiographs were exposed for that particular individual. The DA was determined using orthopantamography by Willem's method and using intraoral periapical radiograph by Kvaal's method.
The panoramic images were obtained in the Digital Imaging and Communication in Medicine (DICOM) format, were saved as DICOM files on a computer, and were analyzed by using the Adobe Photoshop CS6 image editing program. With the help of a Photoshop generator, the images were enlarged and were adjusted the brightness/contrast, if needed. The obtained panoramic images were used to assess the status of maturation based on calcification of the permanent teeth in the mandibular right side, from the central incisor to the second molar, using Demirjian et al., method [Table 1]. After noting all stages of teeth from the central incisor to the second molar, the developmental status of a particular tooth was calculated in years based on the tables given by Willems et al., [Table 2].  All the values from the central incisor to the second molar thus obtained were summed to obtain an overall maturity score, which will indicate the DA of that particular patient.
|Table 1: Description for developmental stages of tooth by Demirjian et al., method|
Click here to view
Intraoral periapical radiographs of the right mandibular first molar were taken by using paralleling cone technique. The exposed films were developed in an automatic processor in fresh solutions. The developed X-ray films were dried and subsequently coded. Intraoral periapical radiographs were traced on a tracing sheet. On the radiographs obtained, 15 standardized points were marked, based on the original method for DA calculation published by Kvaal et al., and measurements were taken using divider and scale with millimeter calibrations. [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5].
- Tooth length (T)
- Pulp length (P)
- Root length (R)
- Ratio of Pulp width to Root width
- A: Cemento-Enamel Junction
- B: Mid-point between A and C
- C: Mid-root level
The ratios calculated were:
P - Pulp length/root length
R - Pulp length/tooth length.
Ratios of the pulp/root width at three different levels:
At the ECJ (A)
At the midpoint between ECJ and mid root level (B)
At the mid root level (C)
The obtained values were applied to the formula developed to estimate the age from the right mandibular first molar given by Kvaal and coauthors.
Age = 33.5 – 18.6 (M) – 3.49 (W − L)
W = Mean value of width ratios from levels B and C
L = Mean value of length ratios P and R
W − L = Differences between W and L
The estimated age was compared with the chronological age recorded and the efficacy of the formula in estimating the age was evaluated.
The data were analyzed using Statistical Package for Social Sciences (SPSS) software version 16.0 (Windows version 17.0 SPSS Inc., Chicago, IL, USA). The level of significance (α) was fixed at 5% (p ≤ 0.05). The student's t-test was used to analyze the significance between the two different age estimation methods.
For evaluating intra-observer reproducibility, 10 intraoral periapical radiographs were randomly selected from the radiography used in this study and rescored of the period of at least 2 weeks and the Cohen Kappa value was calculated. The result of the agreement with the Willem method was not reported, since the calculation that is made is based on the estimation data of the different stages of the maturation of the Demirjian method.
| Results|| |
The study comprises 24 males and 51 females of age ranging from 7 to 32 years. The subjects were divided into five groups, where 7 males and 8 females of age ranging from 27 to 32 years were in group I, 7 males and 8 females of age ranging from 22 to 26 years were in group II, 5 males and 10 females of age ranging from 17 to 21 years were in group III, 2 males and 13 females of age ranging from 12-16 years were in group IV, 3 males and 12 females of age ranging from 7 to 11 years were in group V. Each group comprised of 15 subjects [Table 3].
In this present study, the sample was divided into 5 groups, group I was of ages <32, which shows that the mean DA were found to be 15.9 in Willem's method and 18.88 in Kvaal's method. Group II was of ages <26, which shows that the mean DA were found to be 15.49 in Willem's method and 17.78 in Kvaal's method. Group III was of ages <21, shows that the mean DA were found to be 13.75 in Willem's method and 19.90 in Kvaal's method. Group IV was of ages <16, which shows that the mean DA were found to be 11.85 in Willem's method and 17.69 in Kvaal's method. Group V was of ages <11, which shows that the DA were found to be 7.55 in Willem's method and 17.09 in Kvaal's method [Graph 1].
In the present study, the overall mean difference between the estimated DA and CA for males was 15.10 years while for females was 11.88 years. These gender differences in the entire sample were not statistically significant. When comparison among gender is done, females mature earlier than males, but the mean difference between DA and CA was not statistically significant [Table 4].
Estimated DA assessment by Willem's method appeared to underestimate chronological age both in males and females [Table 5]. However, the difference was greater in females when compared to males. The estimation by Willem's method was compared with the “gold standard” chronological age. The difference was reported as the mean age difference. Mean difference is considered to be a more appropriate measure of accuracy than other measures.
In Kvaal's method, the mean value of pulp chamber height and crown root trunk height, pulpal width at CEJ, and width of the crown at CEJ were assessed, respectively. It was observed that as the age increases the height of the pulp chamber decreases, there was no significant difference between male and female subjects. The width of the pulp at the level of the cementoenamel junction was also found to decrease with age [Graph 2]. The age of the subjects had no influence on the crown root height and the width of the crown at the level of cementoenamel junction.
| Discussion|| |
Forensic dentistry is the application of dental knowledge to those criminal and civil laws that are enforced by police agencies in the criminal justice system. It is the most unexplored and intriguing branch of forensic sciences.
Several methods have been developed to estimate the age of individuals, such as morphological, biochemical, and radiological methods. Most morphological methods require extractions and microscopic preparations of at least one tooth from the individual. These methods cannot be used in living individuals and in cases where it is not acceptable to extract teeth for ethical, religious, cultural, or scientific reasons. Radiographic assessment of age is a simple, non-invasive, and reproducible method that can be employed both on living and unknown dead, either in identification cases or archaeological investigations.
Edwin Saunders showed that teeth were a more accurate assessment of age than height. Gustafson made the earliest systematic attempt to estimate age from radiographs, using macro structural change, and was the most popular age estimation test employed by forensic odontologists and pathologists. Since then age estimation using dental parameters has been used in forensic science.
In 1995, Kvaal et al. presented a method to estimate the age on periapical radiographs, whereas Paewinsky et al. verified the applicability of this method on orthopantomography. In the present study, orthopantomography was used for age prediction. Most of the previous studies on panoramic radiographs, methods of age prediction using pulp tooth ratio were carried out on single-rooted teeth using a regression model. The problems associated with orthopantomography are the superimposition of anatomical structures, especially in the anterior region. Also, the assessment of the pulp cavity of maxillary teeth was found to be difficult because the maxillary posterior teeth are often overlapped by bony structures. So, the right mandibular first molar was chosen for the measurement on the intraoral periapical radiograph. Johanson (1971) found that the correlation between the age and height of the pulp chamber was somewhat stronger than that reported for all teeth in methods for age calculation.
In 1973, Demirjian introduced a method (DemI973) that estimated chronological age based on developments of seven teeth from the left side of the mandible. This method has been tested in various populations and has been mostly reported to overestimate the age of an individual. In 2001, Willems et al., evaluated the accuracy of the Demirjian method in the Belgian Caucasian population and modified the scoring system when a significant overestimation was reported. This modification has been evaluated among various communities and has been reported to be more accurate compared with the original method.
Jyotsna et al., reported that Willems method underestimated the mean age of males by 0.69 years and females by 0.08 years, showed that females mature earlier than males in the selected population. The mean difference between DA and CA according to Willems's method was 0.39 years and is statistically significant (P < 0.05).
In Kvaal's method, the mean value of pulp chamber height and crown root trunk height, pulpal width at CEJ, and width of the crown at CEJ were assessed, respectively. It was observed that as the age increases the height of the pulp chamber decreases, there was no significant difference between male and female subjects. The width of the pulp at the level of the cementoenamel junction was also found to decrease with age. The age of the subjects had no influence on the the crown root height and the width of crown at the level of cementoenamel junction.
A recent study by Mohammed et al., conducted among South Indian children concluded that mean DA showed significant underestimation of 0.7 ± 1.69 years and 0.11 ± 1.3 years in boys and girls, respectively. However, a study conducted among the North Indian population by Grover et al. reported that the method overestimated the age of girls and boys by 0.24 and 0.36 years, respectively.
Similar age estimation studies were done on OPG by Cameriere et al., and Bosmans et al., and, P- value > 0.05, indicated no significant difference between the estimated and chronological age. In the present study, the P- value was > 0.05, indicating a significantly positive result and no statistically significant difference between the estimated age and the actual chronological age.
A study published by Sharma and Srivastava in 2010 mentioned the use of digital intraoral periapical radiographs for estimation of the age of individuals, wherein the authors have obtained population specific regression formulae to estimate age based on Kvaal's technique.
Recently, a study has been published by Kanchan-Talreja et al. in which, the original Kvaal's formulae have been tested on digital intraoral periapical radiographs and have led to large errors in age estimation. The authors in the same study have also developed population-specific formulae which again led to errors in age calculation but a smaller extent than applying the original formulae. It is to be noted that the conventional method and prescribed instrumentation (such as stereomicroscope) used in the original study were not used in the above-mentioned studies which could have been a possible reason for the variation in the achieved results.
Limitations of the study
- The difference between the chronological age and calculated age is due to tooth formation stages are not equally spaced during growth and are not of equal duration.
- When a three-dimensional image is projected on a two-dimensional film receptor, a discrepancy may occur in the morphologic measurements of the tooth.
- Proper visual discrimination between formation stages is necessary because it remains subjective and even a one-stage difference may have an impact on DA.
The research, however, does not end here as there are no methods, by which the age of an individual can be precisely estimated. The goal of future research, therefore, must be within practical and financial constraints and respect recognized ethical standards. Properties and shortcomings of the various existing methods must be reviewed systematically to achieve this objective. In addition, the opportunities provided by combining different methods must be examined.
| Conclusion|| |
In this study, a significant relation was found between estimated DA and CA in the Willem method (p-0.00) and Kvaal's method (p-0.05). Both the methods seem to be applicable in estimating the age of both genders. Moreover, it is equally important to realize that no age estimation will accurately determine the exact age for every individual since development naturally varies between individuals. DA is not the same for all children of a specific known age. The most important aspect of DA estimation is to remember that one should not restrict to only one age estimation technique, but to apply different techniques available and perform repetitive measurements and calculations.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient (s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
The authors would like to thank those who participated in this study. They also would like to thank Dr. Prakash MDS, Department of Public Health dentistry, who made this study easier and complete.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]