During which stage does the hygienist employ revisions?

Nearly all external cause codes require:

a. physician documentation before the code can be used. b. additional forms that must be completed before the external cause codes can be reported to the state. c. a 7th-character extension. d. none of the above.

Which of the following mechanisms explains how fluoride works on enamel?

a. Fluoride ions will displace the hydroxide ions in hydroxyapatite, creating fluoroapatite. b. Fluoride ions will increase the number of enamel rods. c. Fluoride ions will decrease the amount of hydroxyapatite. d. Fluoride ions will decrease the penetration of bacteria into enamel.