In the advancing infection front of the caries lesion, multiple
intrinsic and extrinsic factors are released that are stimulatory
to subjacent pulpal parenchyma. Bacterial metabolites
such as acids have been thought to be initiators of pulpal reactions,
yet the buffering capacity of dentin fluid likely attenuates
the pH before it can directly effect a deleterious response,
except when the remaining dentin thickness is minimal