Abstract
There are many reports describing the stable pink coloration of teeth sometimes seen in advanced decomposed cadavers found in damp conditions especially in the cases of strangulation or drowning. Although it seems plausible that seeping of hemoglobin (Hb) or its degradation products into the dentinal tubules induces this post-mortem phenomenon, the precise mechanisms for the development and/or disappearance of pink teeth are left unsolved. Our previous study reported that in experimentally prepared pink teeth, the color produced with oxyhemoglobin (O2Hb) disappeared faster than that produced with carboxyhemoglobin (COHb) or reduced hemoglobin (HHb). In the present paper, we studied the reason why the color with O2Hb disappeared faster than others. Since it is difficult to obtain many tooth samples with intact dentinal tubules, we chose capillaries as a model of dentinal tubules in this study. When capillaries were compared with teeth using O2Hb and COHb, they proved to be a good model for dentinal tubules of teeth. Experiments with capillaries revealed that the pink coloration produced with O2Hb quickly disappeared under a certain condition, i.e. the presence of both enough oxygen and red cell membranes. This quick loss of color was not affected by changes in temperatures between -20°C and 37°C, nor by the presence or absence of preservatives. In cadavers, extremely anoxic environments are usually maintained due to a lack of oxygen supply. Therefore, the pink coloration of teeth can easily be observed if hemoglobins, mainly HHb, are allowed to soak into the dentinal tubules in damp conditions.
