Age estimation based on aspartic acid racemization in caries-affected teeth: need for further explorations
We would like to congratulate the authors for an informative article titled “Age estimation based on aspartic acid racemization in dentine: what about caries-affected teeth?” . The authors have evaluated the aspartic acid racemization (AAR) in dentinal tissues of carious teeth for forensic dental age estimation, and have concluded that caries may significantly affect the accuracy in age estimation based on aspartic acid racemization. We however, have certain reservations on the methodology followed and conclusions drawn in the study that need to be elaborated for better understanding of this very important research.
The authors observed that there is a wide variation in the estimated dental ages to the real ages when dentinal tissues of carious teeth were analysed than the sound teeth. In the context of comparing aspartic acid levels in the dentinal tissues of carious teeth to the sound teeth, maintaining the homogeneity between the test samples (carious teeth) to the control samples (sound teeth) plays a very significant role. The authors have analysed only 25 carious teeth extracted from 23 individuals and have utilized only three non-carious teeth for comparison. Even the age variations of the 23 individuals with carious teeth is too large ranging from 21 to 79 years when compared to the three sound teeth that aged between 17 and 35 years. The results would have been more convincing if equal number of age-matched carious and non-carious teeth were taken for analysis of aspartic acid in the dentinal structure. In this regard, it would have been useful if at least the decade-wise age distribution of the 23 individuals with carious teeth included in the study was shown by the authors.
The authors have divided the test samples under three categories (category 0: no carious lesions visible in the concerned cube, category a: carious lesions cover 30% or more of the cube, category b: carious lesions cover less than 30% of the cube). It would be more informative to the readers, if the authors could explain as to why 30% involvement was taken as a cut-off and how was that 30% area of involvement calculated in the cubes.
Figures 2 to 4 only depict the cubes in relation to age, and the extent of deviation in age based on AAR. Surprisingly, as apparent from figures 3 to 4, cubes with more than 30% caries appear to have lesser age deviations than cubes with less than 30% caries. It would have been more interesting to show the age deviations in the different cubes of the same individual, and the effect of caries if any. The authors based on the deviations noted in the study conclude that the analysis of caries-affected teeth should be avoided in forensic practice. It is noteworthy here that even in the three sound teeth, the deviations noted were too large (− 1.87 to 3.69 years) to be acceptable in forensic case work. The authors other conclusion/suggestion that if only carious teeth are available for investigation, at least two teeth from the same individual should be analysed appears purely hypothetical without any sound scientific basis.
Our correspondence thus, emphasises on the need for further explorations on this important area of research on dental age estimation.