The Average Number of Decayed, Missing (Because of Caries), or Filled

Multiple Choice

The average number of decayed, missing (because of caries) , or filled permanent teeth (DMFT) steadily declined from 1967 to 1992 in the United States because of:

A) improved oral hygiene.
B) populations residing in fluoridated water communities.
C) improvements in the design of toothbrushes.
D) the use of dental floss.