###### Abstract  
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 cadavereric 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 putrefractive cadavers have utility in medico-legal assessments.  
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have been used to determine teeth color, such as VITA-classic, which comprises four-letter groups (A-D), and as a general principle, the coloration of a given tooth differs according to the region, namely the incisal, middle, and cervical regions, which have different color densities and translucencies [24, 25, 26]. Therefore, visual color matching must consider both shade and region. However, as mentioned above, most previous reports have evaluated the pink teeth phenomenon without considering the degree and region of discoloration. Although it has been reported that discoloration is generally more pronounced around the region of the cementoenamel junction [10, 11, 14, 15, 16, 21], pink teeth have also been reported in a wide range of crowns. Thus, although both the degree and region of discoloration vary, no previous study has objectively scored discoloration on pink teeth. 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 association of the pink teeth phenomenon with various cadaveric factors such as age, sex, time after death, cause of death, and place of discovery.  
In the present study, we created three grade classifications for the degree and region of discoloration, which we call the \"Score of Pink Teeth Color\" (SPTC) and the \"Score of Pink Teeth Region\" (SPTR), respectively (Figures 1 and 2). We then used these measures to assign scores for every tooth of 68 pink teeth cases and attempted to determine the association of pink teeth with various cadaveric factors.  
analysis. The photographs were obtained according to the guidelines from the American Board of Forensic Odontology. The sex was male in 46 cases (67.6%), female in 20 cases (29.4%), and unidentified in 2 cases (2.9%). The age range was \(<\)20 years in 1 case (1.5%), 20-39 years in 9 cases (13.2%), 40-59 years in 20 cases (29.4%), 60-79 years in 15 cases (22.1%), 80-99 years in 6 cases (8.8%), and unidentified in 17 cases (25.0%).