In order to diagnose and treatment plan a cracked tooth correctly, one must have an understanding of how cracks affect the adjacent tissues. A study done by AAE assessed the pulp conditions and dentin in teeth that were affected by attrition or cracks.
The samples that were examined included eight teeth with severe attrition and twelve posterior teeth that were cracked. These twenty samples were attained consecutively in a private dental practice and the extractions were not connected to this study. Then the teeth were administered for histobacteriologic and histopathologic analyses.
Cracks were found in all teeth including the ones with sever attrition. Each cracked tooth was inhabited by bacterial biofilms.
There was one tooth where the enamel had numerous craze lines, one of which even reached dentin to a narrow depth. In some of the teeth, the crack ended in the dentin. Bacteria occupied the dentinal tubules, particularly when the crack protracted vertically into the dentin. Severe buildups of inflammatory cells existed in the pulp region that were situated below the tubules involved with the crack. The situations where the crack extended to the pulp, the responses varied from acute inflammation to total pulpal necrosis. In most cases where the pulp was affected, symptoms occurred as well. In some circumstances, polymorphonuclear neutrophils migrated from the pulp into the crack space and faced the bacterial biofilm situated within. When the crack stretched to the pulp chamber floor, it was found that pulp reacted severely.
Cracks are always populated with bacterial biofilms. The response of the pulp tissue differs depending on the direction, location and degree of the crack.