ABO blood grouping on dental tissue.

Twenty-five permanent teeth, including eight carious ones whose pulp cavities had been exposed, were used for this research 3-5 weeks after extraction. Phosphate-buffered saline (PBS, at pH 7.2) was employed to extract ABO blood group substance from tooth powder. ABO grouping was performed on blood-stained compresses from the extraction wound (as controls), tooth fragment, tooth powder, and cotton fibers immersed in PBS extract by absorption-elution (AE) technique and on the PBS extracts by the two-dimensional absorption-inhibition (2-D AI) technique. It was found that blood grouping in PBS extracts by 2-D AI yielded reliable results: no false positive results, and a high rate of correct grouping, (24/25), while blood grouping on other dental materials, such as tooth fragments, tooth powders, immersed fibers, by AE gave an unacceptable rate of false positive/negative results.