Age estimation from pulp/tooth area ratio (PTR) in an Indian sample: A preliminary comparison of three mandibular teeth used alone and in combination

doi:10.1016/j.jflm.2011.07.003

Journal of Forensic and Legal Medicine

Volume 18, Issue 8, November 2011, Pages 350-354

https://doi.org/10.1016/j.jflm.2011.07.003 Get rights and content

Abstract

Pulp/tooth area ratio (PTR) method of adult dental age estimation has been examined on few tooth types. We assessed the lateral incisor (LI) and first premolar (PM1) in addition to canine (C) — alone and in combination. Periapical radiographs from 61 Indians aged 21–71 years were examined. PTR of LI produced the best age correlation (r = −0.395) followed closely by PM1 (r = −0.362). The canine revealed the lowest correlation (r = −0.206); among tooth combinations, the three teeth taken together had the best R value (−0.438) followed by LI + PM1 (−0.435), LI + C (−0.406) and C + PM1 (−0.37). The standard errors of estimates (S.E.E.) of the regression analyses for the individual teeth and tooth combinations ranged from ±12.13 to 13.08 years, indicating minimal difference in age estimates using solitary or multiple teeth. Errors were higher than in European groups (±2.5–5 years) which may partly owe to moderate age correlation of secondary dentine deposition in Indians. Moreover, facial soft-tissue superimposition in living subjects evaluated herein possibly precluded optimal tooth and pulp canal visualization. These indicate that the PTR method should be used judiciously in age estimation of living Indian adults, although further studies on larger samples with evenly distributed age-groups is necessary for deriving definitive conclusions.

Introduction

Forensic age estimation is important in clarifying issues pertaining to unknown or disputed ages of living individuals as well as reconstructive identification of the deceased. The teeth are considered a reliable indicator of age and provide a number of parameters for age prediction, and traditional methods of adult dental age estimation require tooth extraction and processing.¹ While extracting normal healthy teeth, unless indicated, is unethical and not practical in living individuals, it may not be permitted even in the deceased when preservation of human remains is deemed essential for a variety of legal and cultural reasons; on the other hand tooth processing has the added disadvantage that it necessitates destruction of dental evidentiary material.

Radiographic evaluation of teeth requires neither tooth extraction nor processing; in post-mortem scenarios, teeth can easily be radiographed using apparatus readily available in most mortuary settings. Importantly, dental radiography is also applicable to the living owing to miniscule radiation exposure. These reasons prompted the development of dental radiographic methods for adult age estimation. Researchers have focused on the changes occurring within the pulp cavity and measuring the alterations — specifically, the deposition of secondary dentine — on radiographs for almost four decades.2, 3, 4, 5 However, these studies examined radiographs of tooth sections or intact extracted teeth and did not analyze X-rays taken in situ. Kvaal et al.⁶ appear to be the first who evaluated radiographs obtained in situ, and also included secondary dentinal deposition within the root canal. While these authors⁶ and others⁷ measured the changes unidimensionally, later researchers used two- and three-dimensional methods to quantify reduction in the pulp chamber and root canal.8, 9, 10

One of these methods calculated the pulp/tooth area ratio (PTR) of maxillary canine and correlated this to age.⁸ The method has elicited more interest than others and has been tested on different teeth,11, 12, 13, 14 large sample sizes,15, 16 and diverse populations.14, 15, 16 An advantage of the method is that it calculates changes in tooth and pulp area, which may be more representative of alterations within teeth than one-dimensional length and width measurements undertaken by Kvaal et al.⁶; area is also more easily calculated and less equipment-intensive than computing pulp and tooth volumes.9, 10

Calculation of the PTR, however, has so far been tested on a limited number of tooth types, namely maxillary canine,8, 12, 13, 15, 17 mandibular canine,12, 13, 15, 16 maxillary incisors,¹⁴ and mandibular second molar.¹¹ Also, the method’s application on multiple teeth has been confined to the assessment of teeth from the same class, namely maxillary and mandibular canines.12, 15, 18

We recently assessed PTR in mandibular canines of Indians,¹⁶ but obtained relatively poor age correlation as well as large errors in the age estimates. One possible approach to improving age prediction is to use multiple teeth and multiple regression models. A ‘natural’ improvement in age correlation and prediction may be expected using multiple teeth, as has been suggested and observed by at least one prominent author (p. 118)¹; moreover, some studies that examined secondary dentinal deposition on radiographs, in particular, observed better age correlations (i.e., higher r/r² values) and superior age estimates (i.e., lower standard errors of estimate, S.E.E.) using mandibular lateral incisor, canines and first premolar together rather than in isolation.6, 19 Also, Cameriere et al.12, 13 assessed PTR on maxillary and mandibular canines and found higher correlation to age as well as better age estimates when both teeth were used in combination. Furthermore, these authors stated that future studies “should aim at acquiring data about other teeth” (p. 1155),¹³ as well as investigate “the use of several teeth together” (p. 128.e5).¹⁵ Since both lateral incisor and first premolar were visible on some of the canine radiographs taken by us previously,¹⁶ we ventured to assess the use of the PTR of these two teeth in age estimation with a two-fold objective: (a) to determine its correlation to age and accuracy in age estimation vis-à-vis canine, and (b) to ascertain if the use of PTR of multiple teeth, particularly of different classes, enhanced age prediction accuracy.

Section snippets

Materials and methods

From our original sample of 178 radiographs,¹⁶ all three teeth, viz., lateral incisors (LI), canines (C) and first premolars (PM1), were clearly visible on 61 (39 males and 22 females). Subjects’ age ranged between 21 and 71 years and was relatively well distributed across the different age-groups (Table 1). Radiographs of the teeth (either left or right side) were made using the paralleling technique.

Details of measuring the pulp and tooth areas may be found in Babshet et al.,¹⁶ who made minor

Results

The paired t-test to evaluate potential observer error revealed statistically significant intra-observer differences in lateral incisor and first premolar measurements (p < 0.05); significant differences were also found in the measurements taken by the second examiner on the premolar (p < 0.05), however, no statistical inter-observer differences were seen in measurements obtained on the lateral incisors (p = 0.81).

The regression correlation coefficients, the S.E.E., and the regression equations

Discussion

In the last decade, a number of new methods for age assessment from teeth have been developed,21, 22 or existing methods refined,23, 24, 25 all of which claim relatively precise estimates. One major drawback of these methods, however, is the need to extract and process teeth, precluding their use in living subjects as well as in jurisdictions that do not permit post-mortem tooth extraction for a variety of legal and cultural reasons. Therefore, techniques that circumvent this limitation have

Conclusion

The evaluation of the pulp/tooth area ratio of three mandibular teeth revealed that the lateral incisor had the highest correlation to age when used alone, followed by the first premolar and canine. The use of these teeth in various combinations did not result in recognizably higher correlation. More importantly, there were little practical differences in the accuracy of age estimates irrespective of whether single or multiple teeth were used, with S.E.E.s ranging between ±12.1 and 13.1 years.

Conflict of interest

None.

Funding

None.

Ethical approval

Ethical approval was obtained from the Institutional Ethical Committee (Ethical Clearance dated 8th August 2008).

Acknowledgment

The authors are grateful to Prof. C. Bhasker Rao, Director, and Prof. Srinath L. Thakur, Principal, S.D.M. College of Dental Sciences & Hospital, Dharwad, for their encouragement and support to research in forensic odontology. The authors extend their gratitude to Prof. K. Satish of the Department of Mechanical Engineering, S.D.M. College of Engineering and Technology, Dharwad, for assistance in the use of AutoCAD program, Dr. Sunil Mutalik for assistance in collecting many of the radiographs

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Age estimation of living individuals has become a crucial part of the forensic practice, especially due to the global increase in cross-border migration. The low rate of birth registration in many countries, hence of identification documents of migrants, especially in Africa and Asia, highlights the importance of reliable methods for age estimation of living individuals. Despite the fact that a number of skeletal and dental methods for age estimation have been developed, their main limitation is that they are based on specific reference samples and there is still no consensus among researchers on whether these methods can be applied to all populations. Though this issue remains still unsolved, population information at a glance could be useful for forensic practitioners dealing with such issues.
This study aims at presenting a scoping review and mapping of the current situation concerning population data for skeletal (hand-wrist and clavicle) and dental methods (teeth eruption and third molar formation) for age estimation in the living.
Two hundred studies on the rate of skeletal maturation and four hundred thirty-nine on the rate of dental maturation were found, covering the period from 1952 and 2020 for a total of ninety-eight countries.
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Identification of Ajnala skeletal remains using multiple forensic anthropological methods and techniques: A bioarchaeological report
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Fragmented and badly damaged commingled human remains present a tough challenge for their identification pursuits in forensic anthropology. Thousands of unknown human remains along with items of contextual identity, reportedly belonging to 282 Indian sepoys killed in 1857, were exhumed mon-scientifically from a disused ancient well at Ajnala (Amritsar, India). In this manuscript, the non-scientific excavation of unknown human remains from the abandoned well, their forensic anthropological strategies for identification purposes, challenges being faced and future possibilities of their biological profiling have been discussed. Multiple methods and techniques like anthropological examinations, odontological profiling, radiological analyses, stable isotope and mitochondrial DNA (mtDNA) analyses were applied to few bones and teeth collected from the Ajnala skeletal assemblage. Though majority of studied bones and teeth were found belonging to adult males, very few of them had morphological, osteological and molecular features questioning the authenticity and validity of the written records. Due to certain ambiguous findings or gaps observed between the anthropological analyses of the Ajnala skeletal remains and the reported versions about their affiliations; certain advanced radiological, chemical and molecular techniques were applied to estimate their probable age, sex and populational affinity. The obtained radiological, isotopic and molecular signatures of the remains were compared with the available databases to estimate their affinity with the individuals of geographic area to whom the remains reportedly belonged to. The maternally inherited mtDNA haplogroup assignments, and stable isotope analysis of carbon and oxygen suggested that the studied human remains belonged to the individuals from West Bengal, Bihar, Odisha, Awadh (presently in Uttar Pradesh) and parts of Meghalaya and Manipur as potential regions of their geographic identity and thus, attributing the victims to be non-local to the site. However, merely on the basis of forensic anthropological examinations of very few bones and teeth (collected out of a huge collection of thousands of bones and teeth); it would be just an unqualified and sweeping conclusion to claim their identity as adult or non-adult, male or female, local or non-local, victims of 1857 mass killings or to the victims of ceremonial sacrifices or criminal activities committed in the past. A sufficient number of bones and teeth along with items of personal identity needs to be examined with multiple scientific techniques to arrive at some valid conclusions about their biological identity.
Age estimation from tooth-pulp area ratio: A preliminary study
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The width of the pulp has been considered as a better indicator of the age in the previous studies conducted by Bosmans et al. [7], Cameriere et al. [8], Kvaal [10] and Solheim [11]. Dehghani et al. [12] used the pulp/tooth area ratio in an Iranian population; Juneja et al. [13] in Karnataka population; Jeevan et al. [14] in Indian population; by Zaher et al. in Egyptians [15]; by Babshet et al. [16] in Indian population; by Afify et al. [17] in Egyptian population and by Misirlioglu et al. [18] in Turkish population. There was no significant difference between the chronological age and the estimated age using the derived linear regression equation, which was in accordance with the previous studies [6,7,12–18,4].
The teeth are considered as a reliable indicator of age and provide several parameters for age estimation. Age estimation from dental radiographs is a non-destructive and straightforward method to obtain information. This preliminary study aimed to establish a relationship between chronological age and the tooth/pulp area ratio in a central Indian population. The digital dental X-ray- OPGs of 46 randomly selected consenting subjects belonging to the age group 18 to 60 years were examined. The tooth area and pulp area of upper maxillary right permanent canine were calculated. A Graph was also plotted on the scattered points to get a linear trend line and equation of the relationship between chronological age and tooth/pulp area ratio. Statistical analysis shows a significant strong positive correlation (R²= 0.99) between age and tooth /pulp area ratio. Linear Regression equation was derived for estimation of age, i.e., y = 6.6554x - 22.578 (where y is the estimated age and x is the tooth-pulp area ratio). The estimated age was accurate up to ± 2 years of the actual age. The result of this preliminary study shows that the tooth/pulp area ratio of the canine may serve as a reliable tool for estimation of age.
Les dents sont considérées comme un indicateur fiable de l’âge et fournissent plusieurs paramètres pour l’estimation de l’âge. L’estimation de l’âge à partir de radiographies dentaires est une méthode simple et non destructive pour obtenir des informations. Cette étude préliminaire visait à établir une relation entre l’âge chronologique et le rapport surface dent/pulpe dans une population du centre de l’Inde. Les radiographies dentaires numériques (OPG) de 46 sujets consentants choisis au hasard appartenant au groupe d’âge des 18 à 60 ans ont été examinées. La région de la dent et de la pulpe de la canine permanente supérieure droite du maxillaire supérieur ont été calculées. Un graphique a également été tracé sur les points dispersés pour obtenir une ligne de tendance linéaire et une équation de la relation entre l’âge chronologique et 1 le rapport la région dent/pulpe. L’analyse statistique montre une corrélation positive forte significative (r carré 0,99) entre l’âge et l le rapport la région dent/pulpe. L’équation de régression linéaire a été calculée pour l’estimation de l’âge, c’est-à-dire, y = 6,6554x - 22,578 (où y est l’âge estimé et x est le rapport de la surface dent-pulpe). L’âge estimé était précis jusqu’à ± 2 ans de l’âge réel. Le résultat de cette étude préliminaire montre que le rapport région dent/pulpe de la canine peut constituer un outil fiable d’estimation de l’âge.
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2018, Forensic Science International
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Several methods have been proposed for age estimation using dental radiographs [12]. The apposition of secondary dentin reduces the area and volume of pulp chamber, thus the analysis of the pulp/tooth area ratio can be employed as a reliable biomarker for ascertaining age [16,24,25]. In the present study, the pulp/tooth area ratio (AR) of canines (upper, lower and both) was measured in 271 digital panoramic radiographs to determine chronological age of Iranian adults.
Age estimation in adults is an important issue in forensic science. This study aimed to estimate the chronological age of Iranians by means of pulp/tooth area ratio (AR) of canines in digital panoramic radiographs.
The sample consisted of panoramic radiographs of 271 male and female subjects aged 16–64 years. The pulp/tooth area ratio (AR) of upper and lower canines was calculated by AutoCAD software. Data were subjected to correlation and regression analysis.
There was a significant and inverse correlation between age and pulp/tooth area ratio of upper and lower canines (r = −0.794 for upper canine and r = −0.282 for lower canine; p-value < 0.001). Linear regression equations were derived separately for upper, lower and both canines. The mean difference between actual and estimated age using upper canine was 6.07 ± 1.7.
The results showed that the pulp/tooth area ratios of canines are a reliable method for age estimation in Iranians. The pulp/tooth area ratio of upper canine was better correlated with chronological age than that of lower canine.
Morphological analysis of the lower second premolar for age estimation of Korean adults
2017, Forensic Science International
Citation Excerpt :
Thus, development of non-invasive, accurate, cost-effective, and simple methods of age estimation is inevitable. The clever use of dental radiologic methods of age estimation can supply this demand, especially when extraction or sectioning of the teeth is not possible [13]. Secondary dentin deposition in adults tooth is a useful indicator of age estimation using dental radiography [9].
This study aimed to examine the applicability of the pulp/tooth area ratio in the lower premolar teeth using panoramic radiography in age estimation of Korean adults.
402 digital panoramic images of Korean adults between 20 and 78 years were analyzed. Following Cameriere et al.’s method, two observers measured the pulp and tooth areas of the lower second premolar on digital panoramic images, and the ratio of pulp to tooth area in the whole tooth (PTR) was calculated. In addition, the whole tooth was divided into coronal and root parts at the cementoenamel junction, and the ratios in the coronal part (PcCR) and root part (PrRR) were also calculated separately. Independent t-test, Analysis of covariance, linear regression, and the standard error of the estimate (SEE) were computed using statistical software. To justify the use of linear regression models for purposes of prediction, diagnostic tests of principal assumptions were also performed.
Independent t-test revealed significant differences in genders. PrRR produced the best age correlation (male, SEE = 10.8; female, SEE = 9.8; total, SEE = 10.4 years), followed closely by PTR (male, SEE = 11.1; female, SEE = 10.3; total, SEE = 10.7 years) and a relatively lower accuracy for PcCR (male, SEE = 14.7; female, SEE = 14.4; total, SEE = 14.6 years). Model assumptions and accuracy for purposes of prediction in PTR and PrRR were satisfied.
The pulp/tooth area ratio using panoramic radiography has the potential as an effective tool for age estimation in the Korean adult population, and the pulp/tooth area ratio in the root part is more accurate than that of the whole tooth. Notably, female has shown higher accuracy compare to male subject.
Age estimation in adults by dental imaging assessment systematic review
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Twelve studies met the inclusion criteria for the quantitative analysis (Table 5). The use of this method has shown a standard error of estimation (SEE) from ±1.2 [42] to ±12–13 years (r = 0.2–0.4) [51] From these studies, 2 reported a median error < ± 5 years [7,38], 6 studies reported an error from ±5 to ±8.5 years [26,40,42–44,46], and three studies reported an error from ±10 to ±13 years [4,47,51]. From the included studies in the qualitative analysis, only one reported significant intra-observer differences in lateral incisors and first premolars (p < 0.05) [51].
The need to rely on proper, simple, and accurate methods for age estimation in adults is still a world-wide issue. It has been well documented that teeth are more resistant than bones to the taphonomic processes, and that the use of methods for age estimation based on dental imaging assessment are not only less invasive than those based on osseous analysis, but also have shown similar or superior accuracy in adults.
To summarise the results of some of the recently most recently cited methods for dental age estimation in adults, based on odontometric dental imaging analysis, to establish which is more accurate, accessible, and simple.
A literature search from several databases was conducted from January 1995 to July 2016 with previously defined inclusion criteria.
Based on the findings of this review, it could be possible to suggest pulp/tooth area ratio calculation from first, upper canines and other single rooted teeth (lower premolars, upper central incisors), and a specific statistical analysis that considers the non-linear production of secondary dentine with age, as a reliable, easy, faster, and predictable method for dental age estimation in adults. The second recommended method is the pulp/tooth width–length ratio calculation. The use of specific population formulae is recommended, but to include data of individuals from different groups of population in the same analysis is not discouraged. A minimum sample size of at least 120 participants is recommended to obtain more reliable results. Methods based on volume calculation are time consuming and still need improvement.

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^☆: Portions of this paper have been presented at the 7th National Conference of the Indian Association of Forensic Odontology, 10–11 April 2010, Life Line Multispecialty Hospital, Chennai, India.

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Original communicationAge estimation from pulp/tooth area ratio (PTR) in an Indian sample: A preliminary comparison of three mandibular teeth used alone and in combination☆

Abstract

Introduction

Section snippets

Materials and methods

Results

Discussion

Conclusion

Conflict of interest

Funding

Ethical approval

Acknowledgment

Forensic Sci Int

Forensic Sci Int

Forensic Sci Int

J Forensic Leg Med

Forensic Sci Int

Forensic Sci Int

Forensic Sci Int

Forensic Sci Int

Forensic Sci Int

Forensic Sci Int

Forensic Sci Int

Forensic Sci Int

Age determination from teeth

Odontologisk Revy

Research on age estimation based on teeth

Jpn J Leg Med

Original communication
Age estimation from pulp/tooth area ratio (PTR) in an Indian sample: A preliminary comparison of three mandibular teeth used alone and in combination☆