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☆
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
References (29)
- et al.
Age estimation of adults from dental radiographs
Forensic Sci Int
(1995) - et al.
Dental age estimation through volume matching of teeth imaged by cone-beam CT
Forensic Sci Int
(2006) - et al.
Age estimation based on three-dimensional measurement of mandibular central incisors in Japanese
Forensic Sci Int
(2009) - et al.
Age estimation from pulp/tooth area ratio in maxillary incisors among Egyptians using dental radiographic images
J Forensic Leg Med
(2011) - et al.
Age estimation by pulp/tooth area ratio in canines: study of a Portuguese sample to test Cameriere’s method
Forensic Sci Int
(2009) - et al.
Age estimation in Indians from pulp/tooth area ratio of mandibular canines
Forensic Sci Int
(2010) - et al.
Age estimation by pulp/tooth area ratio in canines: Cameriere’s method assessed in an Indian sample using radiovisiography
Forensic Sci Int
(2011) - et al.
The application of Kvaal’s dental age calculation technique on panoramic dental radiographs
Forensic Sci Int
(2005) - et al.
The accuracy of three methods of age estimation using radiographic measurements of developing teeth
Forensic Sci Int
(2003) - et al.
Age-at-death diagnosis and determination of life-history parameters by incremental lines in human dental cementum as an identification aid
Forensic Sci Int
(2001)
Dental age estimation of Norwegian adults—A comparison of different methods
Forensic Sci Int
Age estimation
Forensic Sci Int
Age determination from teeth
Odontologisk Revy
Research on age estimation based on teeth
Jpn J Leg Med
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2020, Journal of Archaeological Science: ReportsAge estimation from tooth-pulp area ratio: A preliminary study
2020, Revue de Medecine LegaleCitation Excerpt :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].
Age estimation by canines’ pulp/tooth ratio in an Iranian population using digital panoramic radiography
2018, Forensic Science InternationalCitation Excerpt :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.
Morphological analysis of the lower second premolar for age estimation of Korean adults
2017, Forensic Science InternationalCitation 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].
Age estimation in adults by dental imaging assessment systematic review
2017, Forensic Science InternationalCitation Excerpt :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].
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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.