The effect of molecular size on reflection coefficients in human dentine

D. H. Pashley, M. J. Livingston, G. M. Whitford

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20 Scopus citations


Previous investigations of dentine sensitivity using osmotic stimuli have noted that very high molar concentrations (2-6 M) were required to elicit pain. When hydrostatic pressures were used, far smaller pressures were required, indicating that only a fraction of the theoretical osmotic pressure of solutions is effective for moving fluid across dentine. The ratio of the effective to theoretical osmotic pressures, termed the reflection coefficient (σ). is a measure of the degree of semi-permeability of dentine and can vary from 0 (complete solute permeability) to 1.0 (complete solute impermeability). Dentine discs were placed in a split chamber device connected to a pressure transducer. The effective osmotic pressures of solutions containing solutes of various molecular sizes were determined on sanded, acid-etched and oxalate-treated dentine. Reflection coefficients in sanded dentine increased with increasing molecular size from 3 × 10-4 for sucrose to 0.38 for albumin. Acid-etching produced a statistically significant 5-9 fold decrease in reflection coefficients (increased solute permeability) but oxalate treatment restored them to sanded dentine levels.

Original languageEnglish (US)
Pages (from-to)455-460
Number of pages6
JournalArchives of Oral Biology
Issue number6
StatePublished - 1979

ASJC Scopus subject areas

  • Otorhinolaryngology
  • General Dentistry
  • Cell Biology


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