Pulp Tooth Ratio-Based Age Estimation of Adults Using CBCT Images

Nitin V Muralidhar; Priyanka Nitin; Swathi Kumareswar; Ajith Pillai

doi:10.4103/jofs.jofs_232_21

ORIGINAL ARTICLE

Year : 2021 | Volume : 13 | Issue : 2 | Page : 114-120

Pulp Tooth Ratio-Based Age Estimation of Adults Using CBCT Images

Nitin V Muralidhar¹, Priyanka Nitin², Swathi Kumareswar³, Ajith Pillai⁴
¹ Department of Orthodontics and Dentofacial Orthopaedics, JSS Dental College and Hospital, JSS Academy of Higher Education and Research, Mysore, Karnataka, India
² Department of Oral Pathology and Microbiology, JSS Dental College and Hospital, JSS Academy of Higher Education and Research, Mysore, Karnataka, India
³ Department of Forensic Odontology, JSS Dental College and Hospital, JSS Academy of Higher Education and Research, Mysore, Karnataka, India
⁴ Akash Institute of Medical Science and Research Centre, Devanahalli, Bangalore, Karnataka, India

Date of Submission	22-Oct-2021
Date of Acceptance	09-Nov-2021
Date of Web Publication	14-Jan-2022

Correspondence Address:
Dr. Priyanka Nitin
Department of Oral Pathology and Microbiology, JSS Dental College and Hospital, JSS Academy of Higher Education and Research, Mysore 570015, Karnataka
India

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/jofs.jofs_232_21

Abstract

Introduction: The estimation of the age is of great significance in the various branches including the forensics dentistry. Various teeth have been considered for establishing the age using the pulp tooth ratio (PTR), using cone-beam computed tomography (CBCT) images. Hence, to standardize the protocol and the teeth to be considered for age prediction, we have selected and compared the maxillary and mandibular central incisors and canines, as these are the teeth having the least morphologic disturbances. Materials and methods: One hundred CBCT scans of patients visiting a private imaging center were collected, and the pulp volumes were assessed by the CBCT with sections axially and sagitally using “OnDemand3D Dental software.” The linear regression analysis was performed to know the relation of the variables. The correlation of the variables was estimated using the Pearson correlation coefficient. Results: Maxillary central incisors exhibited more reliability than the maxillary canines for age estimation and among the parameters used, the axial section was found to deliver better prediction percentage than the sagittal ones. Conclusion: Maxillary central incisor PTR can be reliably used to estimate the age of an individual when compared with the canines.

Keywords: CBCT, dental age estimation, forensic odontology, pulp tooth ratio

How to cite this article:
Muralidhar NV, Nitin P, Kumareswar S, Pillai A. Pulp Tooth Ratio-Based Age Estimation of Adults Using CBCT Images. J Orofac Sci 2021;13:114-20

How to cite this URL:
Muralidhar NV, Nitin P, Kumareswar S, Pillai A. Pulp Tooth Ratio-Based Age Estimation of Adults Using CBCT Images. J Orofac Sci [serial online] 2021 [cited 2023 Jun 9];13:114-20. Available from: https://www.jofs.in/text.asp?2021/13/2/114/335843

Key Message: This study highlights the importance of teeth in estimation of age, utilizing the new age imaging systems with a high level of efficiency and accuracy.

Introduction

The estimation of the age is of great significance for many science fields that include the medical, dental, and the forensics, along with the anthropology. It is very difficult to accurately tell the age of the person without any proper documentation.^[1],[2],[3] To estimate the age is still difficult among the adults as the maturation process is total in them and the regression of some organs is dependent on the habits. The age estimation for the adults is not as easy like for the pediatric subjects. Both the dental and the skeletal maturation indices are taken into consideration for the age estimation.^[4],[5],[6] The soft tissues more prone to damage are of less value than the hard tissue in the age estimation. As the dental tissues are very resistant to the damage, they can be useful in estimation of age.^{[7],[8],[9],[10]} When compared with bones, teeth are of better value.^[11],[12] However, the estimation of the age from the teeth may be time consuming, may need costly equipment, and sometimes, the teeth need to be removed from the body.^{[13],[14],[15],[16],[17],[18]} These methods may be difficult to implement in people who are still alive and need age to be estimated. Gustafson has proposed a method to estimate the age of the person by the amount of the secondary dentin deposited in the tooth.^[19] Along with the physical estimation of the age, the radiographic methods have also been used successfully. The radiographic method can be used for both the live and the dead subjects. This method is noninvasive, relatively economic, and causes less physical damage to the body.^[20] Kvaal et al. have proposed a method to estimate the age of the person by the estimation of the secondary dentin using the radiographs where the teeth are measured transversely and longitudinally.^[21],[22] The pulp tooth ratio (PTR) was taken for the estimation of the age for the first time by Cameriere et al.^[23] However, these radiographs were only two-dimensional (2D) and cannot be applied in the special cases such as the crowding or the missing teeth where there is a possibility of the image overlaps. In the above radiographic methods, only 2Ds can be measured such as the mesiodistal and the apicocoronal heights. With the availability of the cone-beam computed tomography (CBCT), the teeth can now be viewed three-dimensionally (3D) and measurements are made more accurately. The disadvantages of the 2D radiographs in the cases of the crowding can now be overcome in the 3D CBCT. Previous research has favored the age estimate by the PTR using the CBCT.^[24],[25] Hence, in our study, we aim to estimate age of the south Indian adults using PTR with CBCT images.

Materials and Methods

Ethical approval for this study (protocol No. 14/2014) was obtained from the institutional ethical committee of JSS Dental College and Hospital, JSS Academy of Higher Education and Research on August 25, 2021.

Sample size calculation

With a confidence interval of 95% and power of 90% to obtain a correlation confidence of 0.3 between PTR and chronologic age, 100 samples were estimated for each type of tooth.^[3] Hence, 100 CBCT scans of patients visiting a private imaging center were collected, and the pulp volumes were assessed by the CBCT with sections axially and sagitally using “OnDemand3D Dental software.” Written consent was obtained from each patient being considered for this study. Only those CBCT reports that are clear without any errors or poor in quality were considered. Each CBCT scan has two maxillary, two mandibular central incisors, two maxillary, and two mandibular canines. Hence, eight individual images can be calculated from a single CBCT. A total of 800 CBCT “images” were considered for the study (100 each of maxillary and mandibular canines and the central incisors). Only those teeth without any pathology and the subjects free of the syndromes are included for the study. Both the genders were considered for the study. Subjects between the ages 19 and 70 years were considered. All the subjects were south Indians. The CBCT used was “Cranex 3D machine (Soredex, Helsinki, Finland),” the images were later analyzed using the “OnDemand3D Dental™ software.” Graphs 1-3 show the pulp volumes assessed by the CBCT in the axial and sagittal sections. The analysis of the images was carried out by a single observer, to avoid any bias. The ratio of the pulp to the tooth in the longitudinal, and the sagittal sections were carried out after tracing was thoroughly performed using the software. The ratio of the pulp to the tooth was measured by the formula by dividing the area of the pulp into the area of the tooth. To determine PTR in the axial plan, first, the longitudinal axis of the tooth from the crown tip to root apex was determined and then, the axial section of the tooth was set at the cementoenamel junction region by scrolling the image at the axial plan of the software. Similar to the sagittal plane, tracing was used to measure the tooth and pulp areas, and then the PTR axial was calculated. The readings were taken three times and the mean were noted. The linear regression analysis was performed to know the relation of the variables. The correlation of the variables was estimated using the Pearson correlation coefficient. SPSS 20.0 (SPSS, Chicago, IL, USA) software; IBM^® SPSS^® Statistics 20.0; IBM SPSS Statistics for Windows, Version 20.0. Armonk, NY: IBM Corp.) was used for the study. The “standard error of estimate (SEE)” and the values of “coefficient of determination (R²)” were calculated, to foresee the standard deviation of the projected age with the real age, and to assess the predictive power of the variables such as section and the type tooth.

Results

No significant variation was observed on the intraobserver variances. [Table 1] summarizes PTR for the means maximum and the minimum values. It was observed that when sexes were compared, PTR decreased with the increase in the real age in all the teeth for the sagittal and the axial sections [Graph 4]. A significant correlation between the chronologic age and physiologic ratio was observed. It was also observed that strongest for the mandibular canines among men for the axial sections, and in women, it was observed for the sagittal sections in the maxillary centrals [Table 2]. For the age estimation, the greatest R² was observed among men for the mandibular canine and among women, maxillary centrals. For the age prediction, the axial sections had the highest power for the R² than the sagittal sections [Graph 5] It was noted that the lowest SEE and highest R² for the maxillary centrals, when the predictive age from the actual age were compared [Table 3], Graph 6].

Table 1 Various measurements observed for pulp tooth ratio

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Table 2 Comparison between the genders for the various sections

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Table 3 Predicting chronologic age by using the regression models

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Discussion

The CBCT has the advantage of manipulating the image so that it can be observed for the minute of the details, for example, it can be enlarged, the depth can be calculated, etc.^{[15],[16],[17],[18],[19]} In addition, unlike other tomographies, the radiation for the CBCT is less, it has better quality than other CT. In the present study, we observed a significant relation between PTR and the age for the axial sections in both the genders. It was also observed that for the axial section, the predictive power was more than the sagittal. Our findings are in agreement to the study by Rai et al.^[3] This can be due to the axial area having lesser forces occlusally. There is also lesser deposition of the secondary dentine in this axis.^{[9],[10],[11]} Our findings are contrary to the study of Lee et al.,^[25] wherein, they found the sagittal sections better than the axial sections for the estimation of the age. This can be attributed to the sample considered for the study. This shows that the age estimation is a variable of the ethnicity.^{[20],[21],[22],[23],[24],[25]} Our study findings stated that correlation coefficient between PTR sagittally and age in mandibular canines in both genders varied significantly. This can be due to the difference in the buccolingual diameter between the men and the women.^{[21],[24],[25]} We observed that the most predictive power and the lowest SEE for the maxillary central incisor are in unison with the study of Wu et al.^[22] In our study, the pulp to tooth ratio was considered unlike other previous studies where the volumes were calculated.

Conclusion

The SEE noted is <10 years in our study, which is a prerequisite for the forensics for the estimation of the age. Hence, we can conclude that CBCT images may be successfully applied for the estimation of age among the South Indians by using the ratio of the pulp to tooth, with the maxillary central incisor being the most reliable tooth to be used for the estimation of age. Further, more studies may be performed by including other teeth and also increasing the sample size on different set of target population. This will help us to gain an insight as to which teeth which may give the required results based on specific scenario.

Acknowledgments

The authors acknowledge the immense help received from the scholars whose articles are cited and included in references of this manuscript. The authors are also grateful to authors/editors/publishers of all those articles, journals, and books from where the literature for this article has been reviewed and discussed. The authors acknowledge all those who have directly and indirectly contributed to this manuscript.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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