If a tooth is beginning to decay, topical fluoride, such as with toothpaste, a rinse or in the saliva is the best line of defense against cavities.
(a tooth; is beginning; ) (a tooth; to decay; ) (topical fluoride, such as with toothpaste, a rinse or in the saliva; is; the best line of defense against cavities)
a tooth a tooth topical fluoride, such as with toothpaste, a rinse or in the saliva
is beginning to decay is
the best line of defense against cavities