Histological appearance of postmortem pink teeth: Report of two cases

Study on the Mechanism of the Pink Tooth Phenomenon Using Bovine Teeth: A Pilot Study

The pink teeth phenomenon has occasionally been observed in forensic autopsies. This study aimed to establish an experimental pink tooth model and an objective color tone evaluation method in order to clarify changes in the color tone of teeth and the relationship with hemoglobin monoxide and its decomposition products and with red pigment-producing bacteria, under various external environmental factors. It was confirmed that the color tone evaluation with ΔE and the L*C*h color space was useful. The results of various examinations using this model showed that color development was suppressed under aerobic conditions, faded early under light, became bright red under a low temperature and showed a tendency to be reddish at 3 days under high humidity and in the presence of soft tissue. The biochemical analysis revealed a significant increase in carboxyhemoglobin at 7 days and a tendency toward increasing the total heme pigment and bilirubin levels over time. The bacteriological analysis revealed that red pigment-producing bacteria increased over time but that the color faded after 7 days. These results suggest that putrefaction greatly affects the pink teeth phenomenon, whereas red pigment-producing bacteria have little effect on the occurrence of pink teeth. However, further studies are needed to clarify bacteriological involvement.

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.

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

The pink teeth phenomenon was first reported in people who died by hanging or drowning in 1829. In recent years, there have been many reports that the occurrence of postmortem pink teeth is closely related to the condition of surroundings and time after death rather than to the cause of death, as had previously been thought. We observed pink teeth in 68 of 324 unidentified cadavers autopsied during 2015-2021, and we investigated the relationship of pink teeth with age, sex, cadaveric condition, time after death, tooth type, and cause of death. The results showed no significant differences in the occurrence of pink teeth according to sex or place of discovery (indoors, outdoors, or in water). Pink teeth tended to be observed below the age of 60 years. In the 68 cases with pink teeth, 29.1% of all vital teeth were affected, with the anterior teeth being most common. No evidence was found that supported an association between pink teeth and cause of death. These results are largely consistent with recent reports on postmortem pink teeth. As it stands, the pink teeth phenomenon may be nonspecific and must not be misinterpreted in medico-legal investigations. This case series provides further evidence supporting recent reports and contributes to clarifying in greater detail the mechanisms of the coloration and fading of pink teeth.

Case-specific characteristics of pink teeth in dental autopsies - A systematic review

The cadaveric alterations that derive from the decomposition of the human body are often investigated and examined in medical autopsies together with any other evidence of thanatological interest. This study aimed to systematically review case-specific characteristics of dental autopsies that reported the pink tooth phenomenon (PTP). The review was performed in October/2018 and followed PRISMA and Cochrane guidelines. Seven databases were searched as primary study sources (PubMed, Scopus, LILACS, SciELO, Web of Science, Science Direct and Embase) and three (OATD, Open Grey and Open Thesis) were searched for "grey literature". Only descriptive studies were collected, namely case reports and case series. The risk of bias among the studies was assessed with The Joanna Briggs Institute Critical Appraisal tool. From each case, the sex and age of the victims were registered, together with the place of body recovery, time of death, cadaveric status, cause of death, and number and position of pink teeth. Additionally, a supplemental quantitative analysis was conducted within a sampled subgroup. Poisson regression with robust variance was used to analyze relative risks of presenting pink teeth according to age and tooth position. Eleven studies out of 1004 were eligible. In total 71 cases of cadavers with pink teeth were reported. Two (2.81%) victims had unknown sex, while 17 (23.95%) were females and 52 (73.24%) were males. The victims were aged between 4 and 85 years (mean age 31.13 ± 13.32). Dental autopsies registered 331 pink teeth (163 anterior, 87 premolars and 81 molars). The age did not influence on presenting an additional pink tooth, regardless of tooth position (p > 0.05). Forensic dentists must be aware of pink teeth in dental autopsies. This is an unspecific phenomenon and must not be misinterpreted in medico-legal investigations.

Forensic thanatology and the pink tooth phenomenon: From the lack of relation with the cause of death to a potential evidence of cadaveric decomposition in dental autopsies - Case series

Forensic thanatology comprises the investigation of every phenomenon related to death performed through cadaveric exams. The pink tooth phenomenon (PTP) emerges as a thanatological finding registered during medical or dental autopsy. The PTP consists of a reddish or pink coloration caused in the teeth by the penetration of pulpal hemoglobin in the dentinal tubules. Initially, the PTP was associated with specific violent deaths, such as drowning, hanging and poisoning. However, scientific reports have pointed towards the occurrence of PTP as an expression of cadaveric decomposition regardless of the cause of death. The present study aims to report eight dental autopsies of victims of violent death that presented the PTP. The autopsies were conducted by forensic pathologists and dentists between 2013 and 2018. Seven victims were males and one was female. The age ranged above 6years old. Cranio-encephalic trauma, firearm shooting and asphyxia figured as the causes of death. All the victims were in advanced decomposition. The PTP was detected in deciduous and permanent, anterior and posterior and maxillary and mandibular teeth. Forensic experts, especially dentists, must be aware of the PTP for more detailed registration of postmortem findings and more accurate cadaveric exams.

Oral Pathology in Forensic Investigation

Forensic odontology is the subdiscipline of dentistry which analyses dental evidence in the interest of justice. Oral pathology is the subdiscipline of dentistry that deals with the pathology affecting the oral and maxillofacial regions. This subdiscipline is utilized for identification through oral and maxillofacial pathologies with associated syndromes, enamel rod patterns, sex determination using exfoliative cytology, identification from occlusal morphology of teeth, and deoxyribonucleic acid profiling from teeth. This subdiscipline is also utilized for age estimation studies which include Gustafson's method, incremental lines of Retzius, perikymata, natal line formation in teeth, neonatal line, racemization of collagen in dentin, cemental incremental lines, thickness of the cementum, and translucency of dentin. Even though the expertise of an oral pathologist is not taken in forensic investigations, this paper aims to discuss the role of oral pathology in forensic investigation.