The response of pulp to bacteria depends on many
factors, such as the speed of bacterial ingress and the
speed of progress of caries, which can be slow, rapid or
completely inactive (caries tends to be an intermittent process, with periods of rapid activity alternating with
periods of quiescence). Caries progresses quickly
through demineralized enamel, but will progress more
slowly in demineralized but more organic dentine.119 In
young teeth, bacteria may cause the early death of
odontoblasts, and those dentinal tubules devoid of
odontoblast cell processes become dead tracts