Preparation of dentin standard samples for age estimation based on increased aspartic acid racemization rate by heating

Comparison of racemization rates between vital and endodontically treated teeth for age estimation

Amino acid racemization of dentin (AAR) is among the most precise methods for age estimation in unidentified adult cadavers. Although vital teeth are generally used for this technique, cases often have endodontically treated (Endo) teeth only. Therefore, the aim of this preliminary pilot study was to determine the applicability of Endo teeth by comparing AAR rates between vital and Endo teeth. Thirty-six dentin samples from vital teeth and 18 dentin samples from Endo teeth were analyzed, including the maxillary first premolar, maxillary second molar, and mandibular second premolar. Standard calibration curves for the mandibular second premolar and maxillary second molar were compared among vital teeth, Endo teeth, and mixed vital/Endo teeth. Discrepancies between estimated and actual ages were assessed by analyzing the AAR rates for the maxillary first premolar between vital and Endo teeth. The AAR rates for Endo teeth were higher than those for vital teeth in both the mandibular second premolar and maxillary second molar, and the correlation of the standard calibration curve for vital teeth only was highest (r = 0.982836; r = 0.92011467), followed by mixed (r = 0.949579; r = 0.76158) and Endo teeth only (r = 0.896082; r = 0.744991). In the maxillary first premolar, discrepancies were more than 10 years for all 5 Endo teeth, based on the standard calibration curve of vital teeth. The present study suggests that the AAR rates for Endo teeth might be affected by variation in dentin structure between vital and Endo teeth.

Dental Radiographic/Digital Radiography Technology along with Biological Agents in Human Identification

The heavy casualties associated with mass disasters necessitate substantial resources to be managed. The unexpectedly violent nature of such occurrences usually remains a problematic amount of victims that urgently require to be identified by a reliable and economical method. Conventional identification methods are inefficient in many cases such as plane crashes and fire accidents that have damaged the macrobiometric features such as fingerprints or faces. An appropriate recognition method for such cases should use features more resistant to destruction. Forensic dentistry provides the most appropriate available method for the successful identification of victims using careful techniques and precise data interpretation. Since bones and teeth are the most persistent parts of the demolished bodies in sudden mass disasters, scanning and radiographs are unrepeatable parts of forensic dentistry. Forensic dentistry as a scientific method of human remain identification has been considerably referred to be efficient in disasters. Forensic dentistry can be used for either "sex and age estimation," "Medical biotechnology techniques," or "identification with dental records," etc. The present review is aimed at discussing the development and implementation of forensic dentistry methods for human identification. For this object, the literature from the last decade has been searched for the innovations in forensic dentistry for human identification based on the PubMed database.

Biochemical analyses for dental age estimation: a review

Background

For various legal and forensic scenarios, establishing an individual’s age, both living and dead, plays a crucial role. Various morphological, radiographic, and molecular methods can be used for age estimation. In children and adolescents, age estimation is based on the established developmental stages. However, in adults, where the development ceases into maturation, the degenerative changes play a role in determining the age.

Main body of the abstract

In the natural aging process, several molecular changes occur most commonly in the long-living proteins and hard tissues like the teeth and bone. These molecular changes gradually lead to alterations in several organs and organ systems, which can be quantified and correlated with age, including aspartic acid racemization, collagen crosslinks, advanced glycation-end products, and mitochondrial DNA mutations.

Short conclusion

Among the above methods, the racemization of aspartic acid can be considered as the most precise method. The main advantage of using aspartic acid racemization is that the sample can be collected from tissues (teeth) protected from various environmental and nutritional factors. If all the confounding factors are stable, the utilization of advanced glycation-end products can also be considered valuable. Environmental factors like lead accumulations may also help determine the age. However, further studies need to be conducted, focusing on providing a more standardized method. This review provides a concise summary of the biochemical techniques that can be used for estimation of age.

[Comparative assessment of technical approaches to estimating the biological age of a person using chromatographic analysis of dentin]

The study of the amino acid composition of dentin is a new approach to determining the biological age of a person in Russia. Abroad, this method is more studied, but the authors in their research use various equipment and reagents, which makes it difficult to find the optimal technical standard for implementation in domestic practice. We studied the literature over the past 5 years on age estimation by the amino acid composition of dentin. The equipment used in the work and the results obtained were compared. A comparative evaluation of the data made it possible to make an assumption about gas chromatography using mass selective or flame ionization detectors as a method of choice for studying the amino acid composition of tooth dense tissues.