The rationale of the method is to determine the year of tooth formation based on levels of radiocarbon present in tooth enamel.
Radiocarbon, or carbon-14 (C levels in the atmosphere had been relatively stable for several thousands of years (with respect to all carbon).
Analysis based on morphological methods can yield age estimation error margins of greater than ±10 years (for reviews, see Refs.
1 and 2), whereas precise methods such as aspartic acid racemization and radiocarbon analysis report accuracies of ±3 and ±1–2 years, respectively (3–7).
Age determination of unknown human bodies is important in the setting of a crime investigation or a mass disaster because the age at death, birth date, and year of death as well as gender can guide investigators to the correct identity among a large number of possible matches.
Traditional morphological methods used by anthropologists to determine age are often imprecise, whereas chemical analysis of tooth dentin, such as aspartic acid racemization, has shown reproducible and more precise results.
In an ongoing Swedish homicide case where the victim's identity remains unknown, we illustrate how both methodologies can be combined to provide important information as to the year of birth of the deceased, the estimated age of the person at the time of death, and hence the estimated date of death.
The precision of radiocarbon dating of tooth enamel to determine the year of birth of an individual is a particularly valuable forensic tool for police authorities to use to define the group of possible matches in the early phase of the investigation.
These results have been repeated by several investigators, and typically a high correlation between aspartic acid racemization ratio and age has been reported (for a review, see Ref. Despite these overall positive results, not all groups report the same level of accuracy, and inconsistencies do exist (for a review, see Ref. In comparison, radiocarbon analysis of tooth enamel is a relatively new technique (first described in 2005 (4)) and yet to be significantly tested by the forensic community.
Unlike amino acid racemization analysis, radiocarbon dating of enamel provides information about the date of birth of an individual.
As such, aspartic acid racemization and radiocarbon dating currently represent the methods of choice for precise age estimation.
Assessment of age using aspartic acid racemization methodology was first described in 1975 by Helfman and Bada (5) and has since been widely used in forensic age estimation. Thus, the extent of racemization of amino acids may be used to estimate the age of various tissues.
Current methods of age estimation include simple, yet less precise morphological methods (such as evaluation of dental or skeletal morphology) or more complex, yet more accurate laboratory methods (such as racemization of aspartic acid in dentin or tooth enamel or radiocarbon dating of tooth enamel).