Also, the larger crystals are less prone to future attack from the acids."Systemic fluoride--ingested fluoride that is absorbed mainly through the stomach and intestine into the bloodstream--helps to strengthen teeth while they are growing.
Too much loss of minerals without enough replacement leads to tooth decay. When children eat or drink fluoride in small doses, it enters the bloodstream and becomes part of their developing permanent teeth.
The enamel surface composition and calcium-deficient hydroxyapatite or toothpaste treatments were investigated using X-ray photoelectron spectroscopy.
In vitro enamel demineralization was assayed using a p H cycling model and the dissolution of calcium ions from the treated specimens was quantified using ion chromatography.
Swallowed fluorides also become part of the saliva and strengthen teeth from the outside.
Acids are less able to damage tooth enamel strengthened by fluoride.