Passage B most strongly supports which one of the following statements about fiber and grit in a diet?

meisen on June 1, 2018


Where does it say that fiber and grit limit caries formation?

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Christopher on June 3, 2018

Lines 44-50 say that high fiber and grit can wear down teeth making caries less likely but then turns around and says that too much fiber and grit can wear down teeth to the point that caries form in the tooth's pulp.

alymathieu on January 20, 2019

I don't see where it says it can make them less likely?

Ravi on January 20, 2019


The key part of the text to look at is the second half of the second
paragraph of Passage B.

In lines 42 through 44, we're told that increased caries frequency can
occur from alterations in tooth wear.

We're then told in lines 44 through 47 that the wearing down of the
tooth crown reduces caries formation by removing fissures that can
trap food particles.

In lines 47 and 48, the author states, "A reduction of fiber or grit
in a diet may diminish tooth wear, thus increasing caries frequency."
The key thing about this quote is that it also means that the fiber or
grit in a diet is keeping caries frequency down because when fiber or
grit is reduced, caries frequency increases. This also means that when
fiber or grit is increased, caries frequency decreases. This is the
part of the text that shows us that fiber and grit can either limit or
promote caries formation, depending on their prevalence in the diet.

Also note, however, that we have a bit of a 'Goldilocks' situation
going on with the fiber and grit as well because at the end of the
second paragraph of Passage B, we're told that "severe wear that
exposes a tooth's pulp cavity may also result in caries." This means
that adding fiber or grit UP TO A CERTAIN POINT can reduce caries
frequency, but if so much fiber and grit is consumed that dental wear
is severe, then caries frequency can increase.

Nonetheless, we know that fiber or grit—when added in a reasonable
amount so that it doesn't cause severe tooth wear—can reduce the
frequency of dental caries. And we know that very, very little fiber
or grit doesn't dimish tooth wear enough (increasing caries frequency)
and A TON of fiber or grit might wear teeth down too much, also
increasing caries frequency, but a moderate amount that causes
reasonable tooth wear can lower the frequency of caries.

Does this make sense? Let us know if you have any more questions!