In order to examine the effects of advanced periodontitis on the dental pulps, 38 extracted human teeth were examined histologically. The 38 teeth had a positive or negative state in the electric pulp test(EPT). In addition, almost of the 38 teeth had a deep pocket and severe mobility, and floating state. A medical and dental history was elicited. The extracted teeth fixed in 10% neutral formalin solution. The general tissue processing method was followed. The tissue block including the teeth was prepared for optical microscopy using hematoxillin-eosin staining.

Among the 38 periodontally involved teeth, the dental pulps were respectively intact in 12(31%), and a pulp stone(or linear calcifications) was found in 18 teeeth(47%). In addition, 17 teeth(44%) had pulps exhibiting inflammatory reactions with varying intensities, such as hyperemia, pulp abscess, pulp necrosis. Among the 38 periodontally involved teeth, 37 teeth tested a positive to the EPT, and 7 teeth tested negative. The EPT positive 37 teeth had various histological features such as 7 normal pulp(18%), 17 pulp stone(44%), 1 hyperemia (2%), 9 pulpitis(23%), 5 root resorption(13%), 3 pulp abscess(7%), and 3 pulp necrosis(7%). In conclusion, it is suggested that in the EPT positive teeth, advanced periodontally involved teeth can cause inflammation of the dental pulp.