They do this by using sodium fluoride (a very common active ingredient in toothpastes) to strength tooth enamel that aids in the prevention of cavities.
(to strength tooth enamel; aids; in the prevention of cavities) (They; do; this) Context(They do,List([0, 7))):(They; do this by using; sodium fluoride)
They do,List([0, 7))
to strength tooth enamel They They
aids do do this by using
in the prevention of cavities
this
sodium fluoride