Root Canal Access and Negotiation
Self Test
1. Access procedures set the stage for the success or failure of the rest of the root canal procedure, including shaping and obturation outcomes.
a. True
b. False
2. What are the landmarks that help to determine a safe and accurate entry path during negotiation?
a. Radiographs
b. Cervical root contours
c. Proper placement of the rubber dam and clamp
d. A & B
3. What burs are recommended for initial access entry or refinement?
a. Larger burs should be used at this stage, to avoid the small irregularities that several passes with a smaller bur will create
b. The size is not as important as using a water spray (especially for porcelain) to limit the heat transmitted
c. Smaller burs or ultrasonics tips should be used, so that “course” corrections made down the approach path only result in small irregularities (instead of large ones that may create a perf)
d. Ultrasonics alone are the ideal instrument at this stage, because visibility is greatly enhanced with these instruments
4. What is access convenience form?
a. Access openings that are large enough so that it is convenient for the clinician to get to canal openings
b. The straightest possible entry angle into each canal, combined with conservation of tooth structure
c. What G.V. Black called “The Gordian Knot”
d. All of the above
5. Aside from proper instrument selection and use, what other tools must a clinician apply to create a successful access opening?
a. Knowledge of coronal and pulp chamber anatomy
b. Hand-eye coordination
c. Clinical judgement
d. All of the above
6. What are the benefits of using ultrasonic technology for access refinement?
a. It eliminates the need to carefully pick through calcified teeth
b. Access tips provide un-paralleled visual access.
c. When combined with maginification, ultrasonics can create an ideal access opening in a matter of seconds
d. All of the above
7. Where in the root does calcification occur?
a. It begins coronally and advances apically
b. It begin apically and advances coronally
c. It can begin either coronally or apically, depending on the age of the patient
d. None of the above, the concept of calcification is a myth
8. In general, what is the most important precursor to successful negotiation?
a. Proper instrument selection
b. Using a pre-bent negotiating file
c. The clinician’s endodontic anatomic knowledge of the case
d. All of the above factors contribute equally to successful negotiation
9. When taking a pre-operative radiograph, it is not an issue if roots are foreshortened, as long as the apex is visible. If the apex is visible, it is not necessary to re-take the film.
a. True
b. False
10. Why is it important to use an apex locator during negotiation?
a. It is the only reliable and consistent way to determine the canal’s length
b. Using an apex locator will enable the clinician to reach length without needing to take a K-file past the end of the root canal
c. It helps the clinician to create an accurate mental construct of the canal
d. It can tell you if you are long, and exactly how far beyond the canal terminus you are
11. Why is it recommended that an apex locator be used with each negotiation instrument?
a. It allows greater control and less over-extension of initial negotiating files
b. It eliminates unnecessary films when files are not to length
c. It adds a layer of confidence to the accuracy of readings when several files all read to the same or nearly the same length in the canal
d. All of the above
12. Apex locators usually err by placing the file long, not short.
a. True
b. False
13. What is the most simple and predictable way to prevent irreversible blockage during negotiation?
a. Use a crown-down sequence of files, beginning with larger files, and moving to smaller ones
b. Avoid the use of the 15 K-file, as the 15 is the size that most approximates the terminal diameter of the canal, and is most likely to be involved in blockage
c. Always use a lubricant in the pulp chamber during negotiation
d. Always negotiate in the presence of an aqueous irrigant, such as NaOCl
14. How far past the terminus of the root must you be willing to take the #08, 10 and 15 K-files to be certain that you are patent?
a. 1/4 mm
b. No more than 1/2 mm
c. A full 1 mm
d. 1/2 mm
15. What qualities should you look for in a good negotiation instrument?
a. It should be made of nickel titanium, for maximum flexibility
b. It should be as stiff as possible, and stainless steel is the best material for creating stiffness
c. It should be made with twisted flutes, not lathe-cut flutes
d. B & C
16. After a while, negotiation files will no longer advance apically with a watch-winding motion. What file motion is best to use to get the file moving again?
a. Push pull
b. Serial step-back
c. Balanced force
d. A & B
17. What is a common error to avoid during negotiation?
a. Using a serial step-back technique
b. Employing a crown-down procedure
c. Over-using each file in the series
d. B & C
18. There is always an apical point in any calcified canal that is not obstructed, and the tooth can be treated if the clinician can reach that level in the root.
a. True
b. False
19. When picking files into calcified canals, what file series is used?
a. A crown-down series
b. A step-back series
c. A 1/4 turn pull series
d. A crown-down series, followed by a step-back series, followed bya crown-down, etc
20. When negotiating severely curved or irregular canals, what (besides patience) is the key to success?
a. Mapping a mental image of the canal
b. Loose resistance to apical file placement
c. Pre-bending negotiation files
d. A & C
21. What is the best way to pre-bend a file when negotiating tortuous canals?
a. Bend the file on a cotton roll
b. Pinch the file between gloved fingers and over-bend so that the file will maintain its bent shape
c. Use an Endobender plier, which will allow you to smoothly bend the last few millimeters of the file
d. Bend the file around the curved part of a tear-drop stop
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