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Context: Radiographs have an essential role in Chronological Age (CA) estimation and are being used for dental age (DA) determination. Aims: Detecting the validity of Nolla’s method (NM) for the age assessment of Kurdish Iraqi children (KIC). Methods and Material: A retrospective study was performed using orthopantomographs (OPGs) of 354 subjects aged from 4 to 13 years (178 boys and 176 girls) and their recording files. Subjects were divided into nine study groups: 4, 5, 6, 7, 8, 9, 10, 11, 12, and 13 years old. The chronological age (CA) was subtracted from the DA to find the validity of NM; the positive results indicated the overestimation of age, whereas the negative results indicated for underestimation. The data were recorded through a digitalised system using Microsoft Excel worksheet and analysed by Statistical Package for the Social Sciences (SPSS, version 25) programme using the dependent T?test and graphical analysis. The level of P value used in this study was set at < 0.05. Results: The DA is underestimated in ages 9 to 13 in boys and girls. The highest difference in DA–CA was at the age of 9 years (?0.146 ± 0.162). Conclusions: NM for age estimation was slightly overestimated in age groups of 4, 5, 6, 7, and 8 years in boys and girls without statistically significant differences. However, this method underestimated the ages of KIC ranging from 9 to 13 years significantly.
RESUMO
@#Introduction It is important to produce data on the relationship between age and dental degenerative changes in different populations using dental radiography, because the results of the same method could vary according to the population. Aim This study aimed to examine the applicability of the tooth coronal index (TCI) and the pulp/tooth area ratio of the whole tooth (PTR) to develop a population-specific method to accurately estimate the age of Korean adults using digital panoramic radiography. Result The upper and lower canines, as well as the lower first and second premolars of 101 digital panoramic images of Korean adults aged between 20 and 75 years were analyzed. According to the method of Ikeda et al., the height of the crown and the height of the coronal pulp cavity were measured from the cementoenamel junction (CEJ) to the cusp tip and pulp horn; then the TCI was calculated. According to the method of Cameriere et al., the pulp and tooth areas of the whole tooth were measured and the pulp/tooth area ratio (PTR) was calculated. Aside from this, we modified the method such that the whole tooth was divided into the coronal and root parts at the CEJ, with the pulp and tooth areas from the cusp tip to the CEJ designated as the coronal part (PcCR) and from the CEJ to the root apex designated as the root part (PrRR); these parts were measured and their ratios were each calculated. Pearson correlation coefficients, analysis of covariance, linear regression models, 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 4 principal assumptions were also performed. The TCI in an individual tooth showed a poor correlation SEE ranging from 14.9 to 15.4 years. The four-tooth combination model slightly improved on these results, with a SEE value of 14.8 years. In an individual tooth, the PTR and PrRR showed better correlation than TCI, with SEE ranging from 10.7 to 13.9 years and from 10.5 to 13.7 years, respectively. The PTR and PrRR of the lower second premolar were the most accurate of the regression models. The PTR and PrRR in a four-tooth combination model showed the best age correlation, with SEE values of 10.5 and 9.8 years, separately. Conclusion TCI is not thought to be an appropriate method to predict the age of Korean adults. However, PTR in the lower second premolar can be used as an appropriate indicator for age prediction, and PrRR is more accurate than PTR in Korean adults.