The Effect of pH, Temperature and Plaque Thickness on the Hydrolysis of Monofluorophosphate in Experimental Dental Plaque
| Autor: | G.H. Dibdin, E.I.F. Pearce |
|---|---|
| Rok vydání: | 2003 |
| Předmět: |
business.product_category
Dental Plaque Dentistry Dental plaque Phosphates Monofluorophosphate Fluorides Hydrolysis chemistry.chemical_compound parasitic diseases medicine Humans General Dentistry Analysis of Variance Toothpaste business.industry Temperature Hydrogen-Ion Concentration medicine.disease Cariostatic Agents stomatognathic diseases chemistry business Fluoride Ion-Selective Electrodes Toothpastes |
| Zdroj: | Caries Research. 37:178-184 |
| ISSN: | 1421-976X 0008-6568 |
| Popis: | Monofluorophosphate (MFP), an anti-caries agent commonly used in toothpaste, is known to be degraded to fluoride and orthophosphate by bacterial phosphatases in dental plaque. We have examined the effect of pH, temperature, plaque thickness and some ions on this process. Both natural plaque and artificial microcosm plaque incubated with purified MFP at pH 4-10 showed an optimum pH of approximately 8 for hydrolysis. Diffusion and concomitant hydrolysis were examined in an apparatus in which artificial plaque was held between rigid membranes separating two chambers. When MFP diffused through a plaque of 0.51-mm thickness over 4 h it was almost completely hydrolysed at pH 8, but hydrolysis on diffusion decreased as the pH deviated from 8. MFP in toothpaste extract showed a similar pH susceptibility to hydrolysis, according to the inherent pH of the toothpaste. Hydrolysis of MFP in the toothpaste was reduced by no more than 10% when compared with a matched-pH control, suggesting that other toothpaste ingredients had no major influence on hydrolysis. Transport was slower and hydrolysis at pH 6 more complete the thicker the plaque, but hydrolysis was not significantly slower at 23 degrees C than at 37 degrees C. The addition of various potential activating or inhibiting ions at 0.1 and 1.0 mmol/l had small and non-significant effects on hydrolysis. The results suggest that MFP toothpaste should be formulated and used to maximise enzymic hydrolysis of this complex anion, and that plaque pH control is probably the most important factor. |
| Databáze: | OpenAIRE |
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