Starting December 1, 2018, the Self-Instruction program will be exclusively available online. We will still publish Self-Instruction (S-I) exercises at the end of every corresponding General Dentistry article, but now you can pay online, test online, and receive your continuing education (CE) verification online. Earning CE has never been easier. 

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

AGD - Self-Instruction Exercise No. 425 - Fixed Prosthodontics
Fracture resistance of bonded CAD/CAM restorations with standard or extended preparations

Self-Instruction Exercise No. 425
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Exercise No. 425
Subject Code: 610
Fixed Prosthodontics

The 15 questions for this exercise are based on the article Fracture resistance of bonded CAD/CAM restorations with standard or extended preparations on pages 28-32. This exercise was developed by Brooke Elmore, DDS, FAGD, in association with the General Dentistry Self-Instruction committee.

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

  • understand the advantages of using computer-aided design/computer-aided manufacturing (CAD/CAM) for inlay and onlay preparations;
  • recognize ideal restorative materials for these types of procedures based on the outcomes of this study; and
  • understand the limitations of preparation design.

Answers for this exercise must be received by June 30, 2019.

  1. Which component of inlay and onlay procedures has CAD/CAM improved?

    A. bonding
    B. esthetics
    C. provisional restoration
    D. occlusion

  2. CAD/CAM technology was initially developed to make restorations easier, faster, and more accurate. It has been reported that marginal adaptation values of 5-8 µm have been achieved.

    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.

  3. Unmilled lithium disilicate blocks achieve their color from the _____________.

    A. final shade choice
    B. partial crystallization phase
    C. cement shade choice
    D. tempered phase

  4. Which of the following is a disadvantage of lithium disilicate as a restorative material?

    A. low flexural strength
    B. accuracy
    C. increased chair time
    D. low modulus of elasticity

  5. All of the following are advantages of resin nanoceramics except one. Which is the exception?

    A. ability to repair
    B. decreased milling time
    C. flexural strength
    D. easily adjustable

  6. Which aspects of fracture resistance did the authors test?

    A. preparation type and restorative material
    B. degree of taper and restorative material
    C. preparation type and thickness of material
    D. degree of taper and thickness of material

  7. The extended preparation teeth had a remaining wall thickness of ____ mm.

    A. 1.0
    B. 2.0
    C. 3.0
    D. 4.0

  8. Which teeth were used in this study?

    A. first premolars
    B. second premolars
    C. second molars
    D. third molars

  9. Of the restored teeth, which preparation group had the fewest catastrophic fractures?

    A. standard resin nanoceramic
    B. extended resin nanoceramic
    C. standard lithium disilicate
    D. extended lithium disilicate

  10. Which group demonstrated the greatest number of catastrophic, nonrestorable fractures?

    A. lithium disilicate, extended preparation
    B. negative control, nonrestored teeth
    C. positive control, unprepared teeth
    D. resin nanoceramic, standard preparation

  11. Which group fractured under the lowest load?

    A. unprepared teeth
    B. extended preparation
    C. standard preparation
    D. unrestored teeth

  12. What did the 6-mm probe allow?

    A. engagement of the natural tooth structure
    B. even application of force to the restorative material
    C. off-axis loading of the tooth
    D. smaller area of load

  13. Which material behaves most like natural dentin?

    A. feldspathic porcelain
    B. lithium disilicate
    C. resin nanoceramic
    D. conventional composite

  14. The mean masticatory force in humans is ____ N.

    A. 30
    B. 40
    C. 50
    D. 60

  15. Resistance to fracture of bonded CAD/CAM restorations ___________ as the remaining cusp width _____________.

    A. increases; decreases
    B. decreases; decreases
    C. decreases; increases
    D. increases; increases


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