Aetiological, predisposing and environmental factors in dentine hypersensitivity.

If the hydrodynamic theory of stimulus transmission across dentine is valid, sensitive dentine has tubules open at the surface and patent to the pulp. Direct and indirect evidence supports this supposition. Factors that result in dentine exposure remove the covering enamel or periodontal tissues (gingival recession). Epidemiological and clinical data for the distribution of exposed cervical dentine indicate that chronic trauma from physical and chemical factors is the most significant aetiological factor. Brushing with a toothpaste may not open dentinal tubules. It is more likely that toothpaste ingredients, when brushed on dentine, would create a smear layer. Exposure of tubules by erosion is probably the major initiator of sensitivity. An increase in our understanding of the aetiological factors involved in dentine hypersensitivity is essential if a sound approach to its management is to evolve. Such information could emanate from epidemiological studies, clinical investigations and laboratory experiments.