Orthodontic Treatment: Real Risk for Dental Age Estimation in Adults?

Dental age estimation becomes a challenge once the root formation is concluded. In living adults, one dental age indicator is the formation of secondary dentine, also associated with orthodontic treatment as well as root shortening. The aim of this study was to establish whether these secondary effects of orthodontic treatment could generate a statistically significant difference in dental age estimations when using Kvaal's method. The study sample included 34 pairs of pre- and postorthodontic panoramic radiographs, from different individuals with exactly the same age and sex distribution. Females 65%, median age 17.5 years, and males 35%, median age 22.5 years, were included. After data collection, dental age was estimated per tooth using formulae previously published. The risk of obtaining over-estimation of age was calculated. (RR = 1.007). The changes caused by orthodontic treatment do not have any significant effect on age estimation when Kvaal et al.'s method is applied on panoramic radiographs.

Application of the Kvaal method for adult dental age estimation using Cone Beam Computed Tomography (CBCT).

Different non-invasive methods have been proposed for dental age estimation in adults, with the Kvaal et al. method as one of the more frequently tested in different populations. The purpose of this study was to apply the Kvaal et al. method for dental age estimation on modern volumetric data from 3D digital systems. To this end, 101 CBCT images from a Malaysian population were used. Fifty-five per cent were female (n = 55), and forty-five percent were male (n = 46), with a median age of 31 years for both sexes. As tomographs allow the observer to obtain a sagittal and coronal view of the teeth, the Kvaal pulp/root width measurements and ratios were calculated in the bucco-lingual and mesio-distal aspects of the tooth. From these data different linear regression models and formulae were built. The most accurate models for estimating age were obtained from a diverse combination of measurements (SEE ±10.58 years), and for the mesio-distal measurements of the central incisor at level A (SEE ±12.84 years). This accuracy, however is outside an acceptable range in for forensic application (SEE ±10.00 years), and is also more time consuming than the original approach based on dental radiographs.

Accuracy of a cut-off value based on the third molar index: Validation in an Australian population.

According to Recommendation N°196 of the Australian Law Reform Commission (ALRC), the age at which a child reaches adulthood for the purposes of criminal law should be 18 years in all Australian jurisdictions. With specific reference to age at majority, the only tooth with development spanning adolescence (and thus the legally relevant 18 years of age) is the third molar, which limits the number of methods that can be applied from those available in the published literature. The aim of the present study is to test the accuracy of the third molar index (I3M=0.08), based on the correlation between chronological age and normalized measures of the open apices and height of the third mandibular molar, in order to assess the legal adult age of 18 years. Digital orthopantomographs of 143 living Australian subjects (72 boys and 71 girls) are analyzed. The results demonstrate that the sensitivity is 0.90 in boys and 0.90 in girls; associated specificity values are 0.85 and 0.87 respectively. We conclude that the cut-off value of I3M=0.08 is statistically robust and thus valid for forensic application in an Australian population.

Dental age estimation standards for a Western Australian population.

Age estimation in the juvenile skeleton primarily relies on the assessment of the degree of dental and skeletal development relative to full maturity. The timing of the mineralization and eruption of the teeth is a sequential process that, compared to skeletal growth and development, is less affected by extrinsic influences such as nutrition and/or chronic illness. Accordingly, radiographic visualization and analysis of different tooth formation stages are the foundation for a number of widely applied age estimation standards. Presently, however, there is a relative paucity of contemporary dental age estimation standards for a Western Australian population. To that end, the aim of the present study is to develop statistically quantified radiographic age estimation standards for a Western Australian juvenile population. A total of 392 digital orthopantomograms (202 male and 190 female) of Western Australian individuals are analyzed. Following, Moorrees et al. (J. Dent. Res. 42 (1963a) 490-502; Am. J. Phys. Anthropol. 21 (1963) 205-213), dental development and root resorption was assessed. Alveolar eruption was analyzed following Bengston (Northwest Univ. Bull. 35 (1935) 3-9). Stages of dental development were used to formulate a series of age estimation polynomial regression models; prediction accuracy (±0.998 to 2.183 years) is further validated using a cross-validation (holdout) sample of 30 film orthopantomograms. A visual atlas of dental development and eruption was subsequently designed for the pooled sex sample. The standards presented here represent a non-invasive and statistically quantified approach for accurate dental age estimation in Western Australian juvenile individuals.

Age estimation standards for a Western Australian population using the dental age estimation technique developed by Kvaal et al.

In the present global socio-political scenario, an increasing demand exists for age estimation in living persons, such as refugees and asylum seekers, who seldom have any documentation for proof of identity. Age estimation in the living poses significant challenges because the methods need to be non-invasive, accurate and ethically viable. Methods based on the analysis of the pulp chamber are recommended for age estimation in living adults. There is, however, a paucity of studies of this nature and population specific standards in Western Australia. The aim of the present study is therefore, to test the reliability and applicability of the method developed by Kvaal et al. (1995) for the purpose of developing age estimation standards for an adult Western Australian population. A total of 279 digital orthopantomograms (143 female; and 136 male) of Australian individuals were analysed. A subset of the total sample (50) was removed as a cross-validation (holdout) sample. Following the method described in Kvaal et al. (1995), length and width measurements of the tooth and pulp chamber were acquired in maxillary central and lateral incisors; second premolars, mandibular lateral incisors; canines and first premolars. Those measurements were then used to calculate a series of ratios (length and width), which were subsequently used to formulate age estimation regression models. The most accurate model based on a single tooth was for the maxillary central incisor (SEE ±9.367 years), followed by the maxillary second premolar (SEE ±9.525 years). Regression models based on the measurement of multiple teeth improved age prediction accuracy (SEE ±7.963 years). The regression models presented here have expected accuracy rates comparable (if not higher than) to established skeletal morphoscopic methods. This method, therefore, offers a statistically quantified methodological approach for forensic age estimation in Western Australian adults.

Age estimation standards for a Western Australian population using the coronal pulp cavity index.

Age estimation is a vital aspect in creating a biological profile and aids investigators by narrowing down potentially matching identities from the available pool. In addition to routine casework, in the present global political scenario, age estimation in living individuals is required in cases of refugees, asylum seekers, human trafficking and to ascertain age of criminal responsibility. Thus robust methods that are simple, non-invasive and ethically viable are required. The aim of the present study is, therefore, to test the reliability and applicability of the coronal pulp cavity index method, for the purpose of developing age estimation standards for an adult Western Australian population. A total of 450 orthopantomograms (220 females and 230 males) of Australian individuals were analyzed. Crown and coronal pulp chamber heights were measured in the mandibular left and right premolars, and the first and second molars. These measurements were then used to calculate the tooth coronal index. Data was analyzed using paired sample t-tests to assess bilateral asymmetry followed by simple linear and multiple regressions to develop age estimation models. The most accurate age estimation based on simple linear regression model was with mandibular right first molar (SEE ±8.271 years). Multiple regression models improved age prediction accuracy considerably and the most accurate model was with bilateral first and second molars (SEE ±6.692 years). This study represents the first investigation of this method in a Western Australian population and our results indicate that the method is suitable for forensic application.