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Participants must answer at least 12 of 15 questions correctly (80%) to earn CE credit.

AGD - Self-Instruction Exercise No. 404 - Esthetics/Cosmetic Dentistry
Effect of high- or low-concentration bleaching agents containing calcium and/or fluoride on enamel microhardness

Self-Instruction Exercise No. 404
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Exercise No. 404
Subject Code: 780
Esthetics/Cosmetic Dentistry

The 15 questions for this exercise are based on the article Effect of high- or low-concentration bleaching agents containing calcium and/or fluoride on enamel microhardness on pages 66-70. This exercise was developed by Kim Capehart, DDS, MBA, PhD(c), in association with the General Dentistry Self-Instruction committee.

Reading the article and successfully completing this exercise will enable you to:

  • describe the effects of various bleaching agents on microhardness;
  • learn the effects of calcium and/or fluoride in various bleaching agents; and
  • recognize the differences between low- and high-concentration bleaching agents.

Answers for this exercise must be received by April 30, 2018.

  1. High-concentration hydrogen peroxide (HP) was applied during ___ sessions.

    A. 3
    B. 5
    C. 7
    D. 9

  2. Knoop microhardness measurements were taken from the enamel surface before, during, and ___ days after the end of bleaching.

    A. 7
    B. 14
    C. 21
    D. 28

  3. All of the following influence enamel microhardness values except one. Which is the exception?

    A. composition
    B. concentration
    C. application protocol
    D. dentinal tubule concentration

  4. What statistical test showed that enamel bleached with Whiteness HP Maxx presented lower microhardness values than enamel bleached with other products?

    A. Tukey test
    B. Student-Newman-Keuls test
    C. Dunnett test
    D. Scheffé multiple contrast

  5. Peroxide decomposes into which free radical?

    A. calcium
    B. hydrogen
    C. magnesium
    D. oxygen

  6. With at-home bleaching, low concentrations of carbamide peroxide (20%) or HP (up to 10%) are applied by the patient. With in-office bleaching, higher HP concentrations of 50% are used.

    A. Both statements are true.
    B. The first statement is true; the second is false.
    C. The first statement is false; the second is true.
    D. Both statements are false.

  7. Studies have shown _____ enamel erosion when 35% HP enriched with calcium was used and ______ hardness when 35% HP enriched with both calcium and fluoride was used.

    A. less; lower
    B. less; higher
    C. more; lower
    D. more; higher

  8. Alexandrino et al concluded that a high-concentration HP bleaching agent combined with calcium ___________ prevented a decrease in enamel microhardness.

    A. gluconate
    B. hydroxide
    C. nitrate
    D. peroxide

  9. How many extracted teeth were used in the study?

    A. 10
    B. 20
    C. 30
    D. 40

  10. Freshly extracted third molars were stored in ___% thymol solution.

    A. 0.1
    B. 0.2
    C. 0.3
    D. 0.4

  11. The teeth were examined for cracks, wear, fractures, or stains under a stereoscopic microscope at ___× magnification.

    A. 10
    B. 20
    C. 30
    D. 40

  12. Baseline microhardness measurements were performed on ___ enamel slabs.

    A. 50
    B. 60
    C. 70
    D. 80

  13. Three microhardness indentions were performed on each enamel surface of each block _____ µm apart.

    A. 100
    B. 200
    C. 300
    D. 400

  14. The teeth receiving high-concentration HP bleaching agents were stored in artificial saliva for ______ days.

    A. 7
    B. 14
    C. 21
    D. 28

  15. The data were checked for normality and equality of variance and analyzed using __________.

    A. 1-way ANOVA
    B. Tukey test
    C. 2-way ANOVA
    D. linear regression


Please respond to the statements below, using the following scale:
1 Poor; 2 Below average; 3 Average; 4 Above average; 5 Excellent

Practicality of the content 1 2 3 4 5
Benefit to your clinical practice 1 2 3 4 5
Quality of illustrations 1 2 3 4 5
Clarity of objectives 1 2 3 4 5
Clarity of exercise questions 1 2 3 4 5
Relevance of exercise questions 1 2 3 4 5
Did this exercise achieve its objectives? Yes No
Did this article present new information? Yes No
How much time did it take you to complete this exercise? mins