|FORENSIC ODONTOLOGY: ORIGINAL ARTICLE
|Year : 2019 | Volume
| Issue : 4 | Page : 353-358
Tooth coronal index (TCI), antegonial angle, and antegonial depth measurement for age estimation using digital panoramic radiograph
Priyanka Tidke1, Sunita Kulkarni2, Vaishali Agrawal1, Ullas Saxena2, Rucha Pandharipande3
1 MGM Dental College and Hospital, Navi Mumbai, Maharashtra, India
2 Guru Gobind Dental College, Burhanpur, Madhya Pradesh, India
3 SDKS Dental College and Hospital, Maharashtra, India
|Date of Submission||05-Jun-2019|
|Date of Acceptance||23-Oct-2019|
|Date of Web Publication||03-Mar-2020|
Dr. Priyanka Tidke
Senior Lecturer MGM Dental College and Hospital, Navi Mumbai, Maharashtra
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Introduction and Aim: Age estimation in living individuals is a relatively recent area of applied research within the forensic sciences. Tooth coronal index (TCI) method of age estimation is based on the relationship of age and size of pulp on dental radiographs. This study was an attempt to device simple, cost-effective method to perform morphometric analysis of dental pulp for age estimation. Materials and Methods: In all, 200 subjects were studied for this study. They were classified into four groups (21–30, 31–40, 41–50, and 51–60 years). Subjects then had undergone digital radiographic procedure [radiovisiography (RVG) and orthopantomogram (OPG)], and morphometric analysis (TCI, antegonial angle, and depth) was done. Results: On analysis of complete models with TCI, antegonial angle, and depth, there were 21 (42%) cases with predicted age within ± 5 years in the test data set. In the complete data set (n = 200), 78 (39%) cases were predicted with age within ± 5 years. The models derived for the second premolar and with TCI, antegonial angle, and antegonial depth were better predictor of age when compared with model with only single parameter. On predictions based only on TCI, both the OPG and RVG methods were at par with regard to the overall prediction. Conclusion: There are no significant differences in correlation of age with TCI using OPG and RVG. Correlation of age when three parameters (TCI, antegonial angle, and antegonial depth) are combined is more significant when compared with TCI alone.
Keywords: Antegonial angle, antegonial notch, orthopantomogram, radiovisiography, tooth coronal index
|How to cite this article:|
Tidke P, Kulkarni S, Agrawal V, Saxena U, Pandharipande R. Tooth coronal index (TCI), antegonial angle, and antegonial depth measurement for age estimation using digital panoramic radiograph. J Indian Acad Oral Med Radiol 2019;31:353-8
|How to cite this URL:|
Tidke P, Kulkarni S, Agrawal V, Saxena U, Pandharipande R. Tooth coronal index (TCI), antegonial angle, and antegonial depth measurement for age estimation using digital panoramic radiograph. J Indian Acad Oral Med Radiol [serial online] 2019 [cited 2020 Jul 2];31:353-8. Available from: http://www.jiaomr.in/text.asp?2019/31/4/353/279844
| Introduction|| |
Aging is an unavoidable, inevitable process, beginning at conception and ending with death. Age estimation (sometimes known as age evaluation, age determination, age diagnostics, or age assessment) in living individuals is a relatively recent area of applied research within the forensic sciences. Its value and importance as an assessment tool has risen exponentially as the needs for an informed opinion on the age of an individual have assumed increasing importance for the assessment of both criminal culpability and legal/social categorization. Chronologic age estimation of individuals has a major impact in the field of forensic odontology and regarded as a basic and vital parameter in the age estimation of deceased person.
The natural teeth are the most durable organs in the bodies of vertebrates, and humankind's understanding of their own past and evolution relies heavily on remnant dental evidence found as fossils. Once a tooth is fully mineralized and erupted, it forms a very stable entity. Both developmental and regressive changes to the tooth can be related to chronological age. Furthermore, a tooth will resist the influence of many factors and disintegrates only very slowly., This makes teeth very suitable for dental age estimation.
Several methods have been developed for age estimation based on dental tissue and tooth morphology which are classified into two broad categories: morphologic and radiologic methods which are further classified into clinical, histologic, and biochemical methods.
Easily applied method of age estimation is based on the evaluation of secondary dentine deposition on radiographs. Tooth coronal index (TCI) method of age estimation is based on the relationship of age and size of pulp on dental radiographs.
Apart from the tooth, other craniomaxillofacial structure like various parts of mandible can be used to estimate age of an individual. During an individual's life, the morphological changes undergone by the mandible are thought to be influenced by dental status and the age of the patient. The upward curving of the inferior border of the mandible anterior to the angular process (gonion) is known as antegonial notching. It lies at the junction of body and the ramus.
Conventional radiographic methods are used to determine age because secondary dentine deposition and the changes in the size of pulp can be evaluated. Most of the studies use conventional radiographic methods for age estimation.
There are various disadvantages of conventional radiographic method such as processing errors, storage for longer duration, image transfer, and the measurements are difficult to make. Dental digital radiography evolved in late 1980s. Advances in silico n technology and software development are making its use more precise and practical. Digital systems are accompanied by software tools which make use of digital radiographic techniques easy and rapid.
Digitization of panoramic radiographs and intraoral periapical radiographs and their computerized storage have recently become available. These procedures exploit image analysis to obtain nondestructive metric measurements of some morphological parameters of teeth, which are relatively precise and accurate methods. They improve the reliability, and consequently the statistical analysis of data.
Very few studies have been carried out to evaluate age estimation based on morphometric dental pulp analysis using radiovisiography (RVG) and its comparison with morphometric dental pulp analysis using orthopantomogram (OPG).
This study is an attempt to device simple, cost-effective method to perform morphometric analysis of dental pulp for age estimation and to study age changes on antegonial angle and antegonial depth measurements as well as to establish age prediction equation using TCI, antegonial angle, and antegonial depth measurements for age estimation.
| Materials and Methods|| |
The subjects reporting to the outpatient Department of Oral Medicine and Radiology, Swargiya Dadasaheb Kalmegh Smruti Dental College and Hospital, Wanadongri, Nagpur, were included in this study. The need for the study and usefulness of the study was explained to each patient and informed consent was obtained.
A total of 200 subjects were studied for this study. They were classified into following four groups and 50 subjects in each group were studied:
- 21–30 years
- 31–40 years
- 41–50 years
- 51–60 years.
The procedure involved clinical examination, digital radiographic image capture, and measurements from subjects obtained from the Department of Oral Medicine and Radiology at Swargiya Dadasaheb Kalmegh Smruti Dental College and Hospital, Wanadongri, Nagpur.
The subjects were made to sit comfortably in a dental chair and examination was carried out using a mouth mirror and a straight probe. The examination was required to confirm that the teeth under study (i.e., second premolar and first molar of any one side) were present, and if present, they were neither carious nor restored. In addition, individuals with severe periodontal or restorative dentition were not included in the study. It was further assured that the antagonists of these teeth were present. Next, patient's demographic data such as name, age, sex, address, and date of birth were recorded. Later, the subjects were transferred to radiography section for digital radiographic procedure.
The study subjects were briefed about the radiographic procedures. A standard panoramic radiographic examination of the selected individuals was conducted using ORTHOPHOS XG X-ray system (version 2.53; Sirona, Germany). The measurements were taken using “Sidexis” software.
The patient was explained about the procedure. The patient was asked to sit upright on conventional dental chair to decrease the artifacts that could be cast onto the image. The occlusal plane was aligned so that it was parallel to the floor. The radiographs of the second premolars and first molars were taken from the same side as that of the side of OPG from which readings were taken. For periapical view, size #2sr CCD-based sensor (SuniRay) was used with sensor dimensions 43.5 × 31.5 mm. Radiographs were taken by paralleling angle technique. The measurements were taken using “SuniRay” software.
Analysis of various parameters
Morphometric analysis on OPG and RVG
One of the features of the software is that it allows linear and curvilinear measurements between any two points or multiple points.
A straight line traced between the cementoenamel junctions is the division between the anatomical crown and root. The crown height (CH) was measured vertically from the cervical line to the tip of the highest cusp (Moss et al., 1967). The coronal pulp cavity height (CPCH) was measured vertically from the cervical line to the tip of the highest pulp horn (Ikeda et al., 1985). This measurement provided the TCI for each tooth which was then calculated as follows: TCI = CPCH × 100/CH [Figure 1].
|Figure 1: Schematic representation of measurement of coronal height (CH) and coronal pulp clavity height (CPCH) on the first molar|
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The measurements similar to those in the first molars were proposed to be made in the second premolar as well [Figure 2].
|Figure 2: Schematic representation of measurement of coronal height (CH) and coronal pulp cavity height (CPCH) on the second premolar|
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Antegonial angle measurement
The antegonial angle was measured by tracing two lines parallel to the antegonial region that will intersect at the deepest point of the antegonial notch [Figure 3].
Antegonial depth measurement
The antegonial depth was measured as the distance along a perpendicular line from the deepest point of the notch concavity to a tangent through the inferior border of the mandible [Figure 4].
The data obtained, using the materials and methodology described above, were tabulated, sorted, and statistically analyzed using regression analysis to enable discussion and conclusions.
| Results|| |
A correlation study consisting of 200 subjects is undertaken to study the degree of relationship between age and TCI in premolars and molars on OPG and RVG and to compare the two radiographic techniques for age estimation using TCI. The antegonial angle and antegonial depth measurements are also studied to estimate age. The prediction equations are established using TCI, antegonial angle, and antegonial depth to predict age of an individual [Table 1].
[Table 2] shows the distribution of subjects as per se x. The number of males was 127 (63%) when compared with 73 (37%) females. The male-to-female ratio was 1:0.57.
[Table 3] provides the descriptive statistics for different parameters corresponding to each tooth based on OPG. For second premolar tooth, the mean coronal height of subjects was 8.22 ± 1.04 mm, while the mean coronal pulp height was 2.53 ± 0.68 mm and the mean TCI was 30.46 ± 0.6.61. For first molar tooth, the mean coronal height of subjects was 8.99 ± 1.07 mm, while the mean coronal pulp height was 2.63 ± 0.7 mm and the mean TCI was 29.14 ± 6.45.
|Table 3: Descriptive statistics for different parameters corresponding to each tooth based on OPG|
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[Table 4] provides the descriptive statistics for different parameters corresponding to each tooth based on RVG. For second premolar tooth, the mean coronal height of subjects was 7.96 ± 0.94 mm, while the mean coronal pulp height was 2.33 ± 0.78 mm and the mean TCI was 28.82 ± 6.55. For first molar tooth, the mean coronal height of subjects was 8.50 ± 1.4 mm, while the mean coronal pulp height was 2.32 ± 0.64 mm and the mean TCI was 26.91 ± 6.43.
|Table 4: Descriptive statistics for different parameters corresponding to each tooth based on RVG|
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[Table 5] provides the descriptive statistics for antegonial measurements as obtained by OPG. The mean antegonial angle of subjects for the right side was 159.53° ± 7.97°, while for the left side the mean antegonial angle was 160.02° ± 7.89°. The mean antegonial depth of subjects for the right side was 2.37° ± 1.19° mm, while for the left side the mean antegonial depth was 2.26° ± 1.11° mm.
|Table 5: Descriptive statistics for antegonial measurements as obtained by OPG|
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[Table 6] provides the linear regression equations for predicting age based on different combinations of antegonial measurements and TCI for two tooth types and by two methods, irrespective of gender.
|Table 6: Linear regression equations for different combinations of method used, tooth type, and antegonial measurements considering both sexes|
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It is evident from [Table 7] that considering both sexes and the complete model with TCI, antegonial angle, and depth, there were 21 (42%) cases with predicted age within ± 5 years in the test data set. In the complete data set (n = 200), 78 (39%) cases were predicted with age within ± 5 years. The predictions were slightly better with this model when compared with those obtained using only TCI. Thus, in summary, the models derived for the second premolar and with TCI, antegonial angle, and antegonial depth were better predictor of age when compared with model with only single parameter. With regard to predictions based only on TCI, both the OPG and RVG methods were at par with regard to the overall prediction. A gender-wise split revealed some differences in prediction.
|Table 7: Age predictions for both males and females using different models (tooth: second premolar)|
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| Discussion|| |
This study for adult age estimation was conducted using digital panoramic radiographs and digital intraoral periapical radiographs. The panoramic technique has the advantage of displaying all the mandibular and maxillary teeth on a single film. The teeth included in this study were mandibular first molar and second premolar in which the pulp chamber had good delineation and mandibular any side dentition arbitrarily taken as the differences between upper and lower dentition and teeth sides are negligible in radiographic adult age determination as shown in previous studies. Then comparison was carried out between digital panoramic radiographs and digital intraoral periapical radiographs for age estimation using TCI.
The linear regression equations were established for predicting age based on different combinations of antegonial measurements and TCI for two tooth types and by two methods, irrespective of gender. Among these, the equation for the second premolar by OPG method had maximum adjusted R2 of 0.153, indicating its better predictive ability when compared with other three models. Hence, age estimation using premolar tooth was better when compared with molar tooth irrespective of gender. This is in contrast to the studies by Żądzińska et al. and Igbigbi and Nyirenda which showed the molar equation estimated age better for males while the premolar equation was for female and combined samples.
Among the total sample, 31.5% of subject's age was estimated within ± 5 years using OPG. This was in co-relatioln with a study conducted by Igbigbi and Nyirenda. They estimated 47.7l6% of cases within ± 5 years.
In this study, age estimlation using TCI by intraoral periapical digital radiograph was also carrlied out. Among total sample, 32% of subject's age was estimated within ± 5 years. There were no significant differences in age estimation using OPG and RVG.
According to gender, there were some differences in age estimation using OPG and RVG. In case of males using OPG, there were 26.7% cases with age prediction within ± 5 years. While by RVG it was 30.7%. Hence, RVG is a better predictor of age estimation using TCI for males. While in case of females using OPG, 42.5% cases were predicted within ± 5 years and 36.9% cases were predicted within ± 5 years using RVG. Hence, OPG is a better predictor of age in females.
In this study, statistically significant differences were obtained between the mean antegonial angle and antegonial depth measurements with respect to age and gender in younger age groups 21–30 years and 31–40 years. This is in contrast to a study conducted by Ghosh et al. (2010) and Dutra et al. In their study, no statistically significant relation was observed between the mean antegonial angle and depth measurement with respect to age, although a trend of decrease in the antegonial angle was observed.
However, while comparing the mean antegonial angle and antegonial depth values on the right and left sides, the left-side values were more than the right side. But statistically no significant differences were observed. While in case of the antegonial depth, statistically significant differences were observed. The mean antegonial depth on the right side was more when compared with the left side.
This is in correlation with a study conducted by Mays who reported that the mean dimension of the right antegonial depth was greater than the corresponding mean dimension recorded for the left antegonial depth.
| Conclusion|| |
In this study, it is noted that the correlation of age with TCI in different age groups is significant with the premolars irrespective of gender.
There are no significant differences in correlation of age with TCI using OPG and RVG.
The correlation of age when three parameters (TCI, antegonial angle, and antegonial depth) are combined is more significant when compared with TCI alone.
A significant correlation was observed in decrease in the antegonial angle and increase in the antegonial depth in younger age groups.
The antegonial angle was more in females while depth was less when compared with males. Hence, the antegonial angle and antegonial depth can be implicated as forensic for gender determination.
The antegonial depth was significantly more on the right side when compared with the left side.
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]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7]