SOME CONSIDERATIONS REGARDING THE USE OF AMINO-ACID RACEMIZATION IN HUMAN DENTIN AS AN INDICATOR OF AGE AT DEATH

An HPLC method is described for simultaneously obtaining the enantiome ric ratio of three amino acids (aspartic acid, serine, and glutamic ac id) from dental collagen, with a view to using this information for es timating age at death. Results are reported from a sample of twenty th ree known age modern teeth, six known age 19th C. AD teeth, and two un known age Romano-British teeth. It was found (as expected) that all th ree D/L ratios changed significantly with chronological age. Standard calibration techniques were used to estimate ages for the six 19th C. AD specimens from regression equations estimated from the modern speci mens, and also to predict (for the first time) the error associated wi th such estimates. Errors using aspartic acid were found to be similar to those obtained by other methods of age estimation from dental evid ence, serine, and glutamic acid providing much poorer age estimates. A dditionally, a systematic difference in the age-enantiomeric ratio rel ationship was observed between modern and older dental samples. It is concluded that there is some fundamental difference in the observed en antiomeric ratios between modern teeth and older samples, possibly as a result of the chemical alteration of the dental proteins.