Don't ignore dentin!
“Dentin is not as impervious as it appears. Although very solid in appearance, dentin is comprised of a network of tubules containing live cells that extend from the odontoblast that lies adjacent to the pulp all the way to the dentin-enamel interface. Exposure to oral bacteria may allow destruction of the cell process and the odontoblast. Bacteria may gain access to the pulp, causing inflammation of the pulp (pulpitis) and eventually results in pulp death and necrosis.”
-Brett Beckman, DVM, FAVD, DAVDC, DAAPM