The effect of increasing sodium fluoride concentrations on erosion and attrition of enamel and dentine in vitro.
OBJECTIVE
To investigate the effect of an aqueous sodium fluoride solution of increasing concentration on erosion and attrition of enamel and dentine in vitro.


METHODS
Enamel and dentine sections from caries-free human third molars were polished flat and taped (exposing a 3 mm x 3 mm area) before being randomly allocated to 1 of 5 groups per substrate (n=10/gp): G1 (distilled water control); G2 (225 ppm NaF); G3 (1450 ppm NaF); G4 (5000 ppm NaF); G5 (19,000 ppm NaF). All specimens were subjected to 5, 10 and 15 cycles of experimental wear [1 cycle=artificial saliva (2h, pH 7.0)+erosion (0.3% citric acid, pH 3.2, 5 min)+fluoride/control (5 min)+attrition (60 linear strokes in artificial saliva from enamel antagonists loaded to 300 g)]. Following tape removal, step height (SH) in mum was measured using optical profilometry.


RESULTS
When the number of cycles increased the amount of tooth surface loss increased significantly in enamel and dentine after attrition and erosion and for dentine after attrition. Attrition and erosion resulted in greater surface loss than attrition alone after 15 cycles of experimental wear of enamel. 5000 ppm and 19,000 ppm sodium fluoride solutions had a protective effect on erosive and attritional enamel tooth wear in vitro, however no other groups showed significant differences.


CONCLUSIONS
The more intensive the fluoride regime the more protection was afforded to enamel from attrition and erosion. However, in this study no such protective effect was demonstrated for dentine.
Austin
R S
RS
Department of Primary Dental Care, King's College London Dental Institute, Caldecot Road, Denmark Hill, London SE5 9RW, United Kingdom. rupert.s.austin@kcl.ac.uk
Rodriguez
J M
JM
Dunne
S
S
Moazzez
R
R
Bartlett
D W
DW
D002327:Cariostatic Agents / Q000008:administration & dosage*; D019343:Citric Acid / Q000009:adverse effects; D003743:Dental Enamel / Q000187:drug effects* / Q000473:pathology; D003804:Dentin / Q000187:drug effects* / Q000473:pathology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008422:Materials Testing; D018613:Microscopy, Confocal; D020011:Protective Agents / Q000008:administration & dosage; D012464:Saliva, Artificial / Q000737:chemistry; D012969:Sodium Fluoride / Q000008:administration & dosage*; D013997:Time Factors; D019217:Tooth Attrition / Q000209:etiology* / Q000473:pathology; D014077:Tooth Erosion / Q000209:etiology* / Q000473:pathology; D014867:Water / Q000737:chemistry
D002327:Cariostatic Agents; D020011:Protective Agents; D012464:Saliva, Artificial; D014867:Water; D019343:Citric Acid; D012969:Sodium Fluoride