Sixty-eight cases of postmortem pink teeth observed in dental autopsies of unidentified cadavers

Forensic significance of postmortem pink teeth: A narrative review

OBJECTIVE

To review the phenomenon of postmortem pink teeth, exploring its etiology, correlation with the cause of death, and the potential forensic significance of this medico-legal finding.

METHODS

A comprehensive literature search was conducted using databases such as PubMed, Scopus, and B-on, employing keywords like "Forensic Pathology," "Forensic Dentistry," "Pink Teeth," and "Medico-legal aspects." The search included studies without temporal limits to gather extensive data on the postmortem pink teeth phenomenon.

RESULTS

The postmortem pink teeth phenomenon is characterized by a red-pink discoloration of the dentin, typically sparing the enamel. It is most often observed in moist environments and cases involving water immersion, strangulation, and carbon monoxide poisoning. The study found no consistent relationship between the pink discoloration and specific causes of death, suggesting the phenomenon is more closely related to environmental conditions and the state of decomposition. The pink coloration is more prevalent in anterior, single-rooted teeth and younger individuals.

CONCLUSION

The postmortem pink teeth phenomenon remains a complex and enigmatic finding in forensic science. While it does not conclusively indicate a specific cause of death, understanding its occurrence can aid forensic investigations. Further research is needed to elucidate this phenomenon's mechanisms and validate its forensic relevance.

Effects on oral tissues of asphyxiation caused by cervical compression: The pink teeth phenomenon in Kato's studies (1941)

The effects on oral tissues of asphyxiation caused by cervical compression were investigated in 203 rabbits by Kiyotoshi Kato, who published four papers in classical Japanese in Kokubyo Gakkai Zasshi (now The Journal of the Stomatological Society, Japan) in 1941. The aim of this review is to summarize and disseminate the enormous amount of experimental data (reprint permission in English has been obtained from the journal). Based on the experimental models of hanging, strangulation with an external force equal to body weight, and strangulation with an external force equal to 1/10th body weight, the macroscopic and histological findings of the oral region immediately after death, including the respiratory condition until death and ocular conjunctival petechiae, were obtained and compared with 4 cases of human strangulation. Strangulation after each of four physical conditions (anesthesia, starvation, alcohol intake, and bleeding) was also investigated. Experiments were performed to investigate the effects of tracheal obstruction, cervical vein ligation, common carotid artery ligation, cervical nerve amputation, or combinations thereof. In the discussion focusing solely on tooth discoloration, it was suggested that the presence of pink teeth at a stage when putrefaction has little or no effect might be a finding indicative of death from asphyxiation caused by cervical compression. This review provides detailed data on the condition of oral tissues after asphyxiation caused by cervical compression and is expected to be used not only for elucidating the mechanism of the pink teeth phenomenon but also for conducting other forensic research.

Association of Cadaveric Factors with the Degree and Region of Discoloration on Pink Teeth: An Approach to Serial Cases

The pink teeth phenomenon has been observed in cases of hanging and drowning, but the relationship of this phenomenon with cause of death has not been positively affirmed. To date, teeth with a pinkish tone have been simply regarded as pink teeth. However, we speculated that classification and evaluation of the degree and region of discoloration with reference to how color is classified in prosthodontic dentistry may produce novel findings regarding the pink teeth phenomenon. Therefore, we classified the degree and region of discoloration on teeth into three grades and attempted to evaluate the relationship of grade with various cadaveric factors in 68 cases of pink teeth. The degree and region scores of discoloration did not show significant differences in terms of sex, age, cause of death, and place of discovery, but the degree of discoloration in terms of time after death showed a significant increase at 6 months (p < 0.01) and a significant decrease after 7 months (p < 0.05), while the region score also showed a significant decrease after 7 months. Furthermore, in 18 cases of drowning, the degree of discoloration significantly increased with time after death (p < 0.01). Thus, it was clarified that time after death was most strongly related to the pink teeth phenomenon, suggesting cadaveric decomposition may affect the occurrence of pink teeth. Further investigation in cases of early postmortem changes would be required to determine whether pink teeth in putrefactive cadavers have utility in medico–legal assessments.