DENTAL AGE ESTIMATION USING THE RADIOGRAPHIC VISIBILITY OF PERIODONTAL LIGAMENT AROUND LOWER THIRD MOLARS AMONG SELECTED NIGERIANS

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O.I Opeodu¹, O.F Sigbeku²

1. Department of Periodontology & Community Dentistry, College of Medicine, University of Ibadan..
2. Department of Oral Pathology, College of Medicine, University of Ibadan, Ibadan.

Abstract

Background: Age estimation for sporting activities, legal age determination and migration purpose is oftentimes essential, which makes the need for a scientifically proven method of age estimation an important aspect of medical practice. Forensic odontology is an essential aspect of forensic practice and may be a veritable tool in age estimation.

Aim and Objective: The objective of this study was to evaluate the usefulness of orthopantomograms (OPG) in age estimation among selected Nigerians.

Methodology: A retrospective assessment of 202 OPGs was done to review the visibility of the periodontal ligament of third molars with completed root formation according to the methods described by Olze et al (2010). Individual ages were then calculated by deducting date of exposure from the date of birth recorded in years. Mean age with standard deviation were calculated for each group.

Results: Assessing the minimum and maximum age at which each of the stages of the radiographic visibility of the periodontal ligament as seen on the OPGs revealed that there was a gradual increase in the age at which the stage increment occurred, with a few exceptions. Comparison of the radiographic visibility of the periodontal ligament revealed that males tend to achieve early periodontal visibility stages compared to females, but the reverse was observed in later stages.
Age 17 is more than likely attained in any person found within stages 1 to 3 as the minimum age found in these stages were above 17 years.

Conclusion: With a few exceptions, the assessment of periodontal ligament visibility on OPGs can adequately predict the age of individuals. Thus, the use of this method may need to be combined with other methods in accurate determination of dental age in instances of forensic age estimation.

Keywords: Age determination, Periodontal ligament, Orthopantomogram, Third molars, Forensic

Introduction

There are instances where establishment of the identity of an individual becomes very important. This may include the estimation of the age of affected individual, for instance in age-grade sporting activities, legal age, age estimation among migrants, and in cases of mass casualty or suspected murder cases.^1-3 Criminals in their bid to escape justice or illegal migrants seeking asylum may claim to be younger than 18 years of age, which may necessitate the determination of their true age, and this can be done with the use of forensic odontology.¹ There is bound to be changes to human body following death, either because of murder or mass casualty, but dental tissues will not decompose at the rate at which soft tissues does, and may be among the last set of tissues to decompose in dead human beings, which provides good source of materials for forensic investigation in case of suspicious death or insurance claim. There had also been instances where victims of serial killers were dissolved in acids, only for dental prosthesis to resist dissolution by the acid, which aids in the resolution of such cases.

The international interdisciplinary Study Group on Forensic Age Diagnostics put forward a guideline for forensic age estimation, which include the following:
a. Clinical examination, including anthropometric measures and assessment of sexual maturity signs
b. Radiographic examination of the left hand
c. Dental evaluation involving clinical examination and analysis of orthopantomograms (OPGs).

If the skeletal development of the hand is completed, an additional radiographic examination or CT-scan of the clavicles need to be done.2 Different methods had been used in the assessment of the dental age estimation and these include the assessment of the visibility of the periodontal ligament of completely erupted lower third molars on OPG.⁴ The other method is the assessment of the root pulp visibility in the lower third molars, which is based on the idea that secondary dentine will keep being deposited in the pulp canal with the resultant narrowing of the pulp canal.⁵ The upper third molars are usually not used because of the superimposition as a result of adjacent structures, which does not allow for clarity of the image in that area.⁶ Olze et al. had reported the benefits of the use of radiographic visibility of periodontal membrane of fully mineralized third molars among Germans who are older than 21 years of age. ⁴ However, due to differences in dentition and eruption sequence from culture to culture, age estimation from one culture may not exactly fit into that of another culture. Therefore, there is the need for the assessment of the orthopantomograms (OPGs) among Nigerians, with the view of correlating with their ages to establish a baseline data for Nigerians. Previous studies reported among Nigerians gave a conflicting report of other methods used not being able to effectively predict the age of their studied population.^7,8 Therefore, this retrospective study of orthopantomograms was to assess the possibility of the use of the method described by Olze et al.⁴ at assessing the radiographic visibility of periodontal membrane and correctly estimating ages of Nigerians.