title: Effects of zinc and fluoride on the remineralisation of artificial carious lesions under simulated plaque fluid conditions.
abstract: The aim was to study the effects of zinc (Zn) and fluoride (F) on remineralisation at plaque fluid concentrations. Artificial carious lesions were created in 2 acid-gel demineralising systems (initially infinitely undersaturated and partially saturated with respect to enamel) giving lesions with different mineral distribution characteristics (high and low R values, respectively) but similar integrated mineral loss values. Lesions of both types were assigned to 1 of 4 groups and remineralised for 5 days at 37°C. Zn and F were added, based on plaque fluid concentrations 1 h after application, to give 4 treatments: 231 μmol/l Zn, 10.5 μmol/l F, Zn/F combined and an unmodified control solution (non-F/non-Zn). Subsequently remineralisation was measured using microradiography. High-R lesions were analysed for calcium, phosphorus, F and Zn using electron probe micro-analysis. All lesions underwent statistically significant remineralisation. For low-R lesions, remineralisation was in the order F(a) < non-F/non-Zn(a) < Zn(a, b) < Zn/F(b), and for high-R lesions F(a) < non-F/non-Zn(b) < Zn(b) < Zn/F(c) (treatments with the same superscript letter not significantly different, at p < 0.05). Qualitatively, remineralisation occurred throughout non-F/non-Zn and Zn groups, predominantly at the surface zone (F) and within the lesion body (Zn/F). Electron probe micro-analysis revealed Zn in relatively large amounts in the outer regions (Zn, Zn/F). F was abundant not only at the surface (F), but also in the lesion body (Zn/F). Calcium:phosphate ratios were similar to hydroxyapatite (all). To conclude, under static remineralising conditions simulating plaque fluid, Zn/F treatment gave significantly greater remineralisation than did F treatment, possibly because Zn in the Zn/F group maintained greater surface zone porosity compared with F, facilitating greater lesion body remineralisation.
authors: GlaxoSmithKline, Weybridge, UK. richard.j.lynch@gsk.com
authors: R J M
authors: RJ
authors: Lynch
authors: D
authors: D
authors: Churchley
authors: A
authors: A
authors: Butler
authors: S
authors: S
authors: Kearns
authors: G V
authors: GV
authors: Thomas
authors: T C
authors: TC
authors: Badrock
authors: L
authors: L
authors: Cooper
authors: S M
authors: SM
authors: Higham
mesh_terms: D000818:Animals; D002118:Calcium / Q000032:analysis; D002327:Cariostatic Agents / Q000032:analysis / Q000494:pharmacology*; D002417:Cattle; D003731:Dental Caries / Q000378:metabolism* / Q000473:pathology; D003743:Dental Enamel / Q000187:drug effects / Q000378:metabolism; D003773:Dental Plaque / Q000378:metabolism*; D017886:Durapatite / Q000032:analysis; D004577:Electron Probe Microanalysis; D005459:Fluorides / Q000032:analysis / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D019344:Lactic Acid / Q000009:adverse effects; D008747:Methylcellulose; D008852:Microradiography; D010758:Phosphorus / Q000032:analysis; D013052:Spectrometry, X-Ray Emission; D013696:Temperature; D013997:Time Factors; D014089:Tooth Remineralization / Q000379:methods; D015032:Zinc / Q000494:pharmacology*
chemical_list: D002327:Cariostatic Agents; D010758:Phosphorus; D019344:Lactic Acid; D008747:Methylcellulose; D017886:Durapatite; D015032:Zinc; D005459:Fluorides; D002118:Calcium