M. Kuroiwa et al., BRUSHING-INDUCED EFFECTS WITH AND WITHOUT A NONFLUORIDE ABRASIVE DENTIFRICE ON REMINERALIZATION OF ENAMEL SURFACES ETCHED WITH PHOSPHORIC-ACID, Caries research, 28(5), 1994, pp. 309-314
The remineralization of acid-etched enamel after brushing with and wit
hout a non-fluoride abrasive dentifrice was investigated using scannin
g electron microscopy after sodium hypochlorite (NaOCl) or ethylenedia
mine tetra-acetic acid treatment, of the specimens. Ground enamel piec
es were etched with 30% phosphoric acid for 60 s and attached to resin
plates. They were exposed to the oral environment of 4 subjects for 8
weeks and brushed for 1 min daily. Paste and brushing caused the acid
-etched enamel to erode selectively, i.e., deep grooves were formed in
the prism peripheral regions, while projections of the prism bodies s
howing a relatively low density of crystallites were retained. Brushin
g without dentifrice, on the other hand, caused about 0.5 mu m thick p
ellicle with tag-like structures to cover the etched enamel. Fine mine
ral granules, presumably derived from saliva and minute fragments of e
tched crystallites, were precipitated on the enamel surface as a thin
layer with the pellicle. These results indicate that daily brushing wi
thout dentifrice induces the remineralization of acid-etched enamel by
depositing salivary components, while paste brushing will lead to abr
asion of the weakened enamel.