MCQs in Endodontics

Chapter 15: Microbiology

 

1- Most root canal infections involve:

  1. a single obligate anaerobic species.
  2. multiple anaerobic species only.
  3. mixed aerobic and anaerobic microorganisms.
  4. multiple aerobic species only.

 

 

 

 

 

The answer is: C

 

2- Studies have demonstrated a correlation between clinical and radiographic signs and symptoms of periapical pathosis and the presence of: 

  1. Streptococcus mutatis.
  2. Prevvtella melaninogenicus.
  3. Staphylococcus aureus.
  4. no specific microorganism(s).

 

 

 

 

 

The answer is: B

 

3- Which mediators of inflammation are considered also to be the main mediators of pain in inflammatory responses?

  1. Vasoactive amines.
  2. Kinins.
  3. Complement.
  4. Arachidonic acid.

 

 

 

 

 

The answer is: B

 

4- The presence of which component of complement in the inflamed periapex suggests that the complement system participates in the pathogenesis?

  1. CI.
  2. C3.
  3. C7.
  4. C9.

 

 

 

 

 

The answer is: B

 

5- Degranulation and release of histamine is usually stimulated by bridging which of the following on the mast cells?

  1. IgA.
  2. IgE.
  3. IgG.
  4. IgM.

 

 

 

 

 

The answer is: B

 

6- Identification of lymphocytes in human periapical lesions has shown:

  1. an absence of B lymphocytes,
  2. b- an absence of T lymphocytes.
  3. that T cells outnumber B cells.
  4. that B cells outnumber T cells.

 

 

 

 

 

The answer is: C

 

7- In periapical lesions, suppressor T cells are associated with:

  1. acute (developing) lesions.
  2. chronic lesions.
  3. healing lesions.
  4. foreign-body lesions.

 

 

 

 

 

The answer is: B

 

 8- Routine culturing of the root canal system is generally not practiced in today's treatment regimens because:

  1. it is time consuming.
  2. important anaerobes cannot be recovered.
  3. standard RCT techniques effectively eliminate the majority of microorganisms.
  4. microorganisms play a minor role in endodontic pathosis.

 

 

 

 

 

The answer is: C

 

9- When antibiotic therapy is indicated before, during, or after root canal treatment the drug of choice is:

  1.  clindamycin
  2. erythromycin
  3. penicillin
  4. metronidazole

 

 

 

 

 

The answer is: C

 

10- Long-term administration of clindamycin is contraindicated because of the risk of developing:

  1. severe gastrointestinal conditions.
  2. urticaria
  3. photosensitivity
  4. hypersensitivity

 

 

 

 

 

 

The answer is: A

  

11- What immunoglobulin predominates in a secondary humoral response?

  1.  IgA
  2. IgG
  3. IgM
  4. IgE

 

 

 

 

 

 

 

The answer is: B

 

12- Elevated levels of IgE have been identified in a periapical granuloma after canal instrumentation. This may represent which type of hypersensitivity reaction?

  1. Type 1 (immediate hypersensitivity).
  2. Type II (immediate cytotoxic hypersensitivity).
  3. Type III (immune complex hypersensitivity).
  4. Type IV (delayed hypersensitivity).

 

 

 

 

 

 

 

The answer is: A

 

13- The cytokine, interleukin-1 (IL-1), has been identified in the inflamed pulp and inflamed periapical lesion. One important function is to:

  1. result in bone resorption.
  2. neutralize bacterial endotoxins.
  3. inhibit inflammation.
  4. promote phagocytosis by macrophages.

 

 

 

 

 

 

The answer is: A

 

14- The intracanal medication that has the best potential for effectiveness as an antimicrobial agent sealed in the canal is:

  1. formocresol
  2. 5.25% sodium hypochlorite.
  3. steroids.
  4. calcium hydroxide.

 

 

 

 

 

The answer is: D

 

15- Coronal exposure of gutta-percha/sealer obturation to bacteria has shown that, throughout the canal, the bacteria:

  1. penetrate very quickly (1 to 3 days) throughout obturation defects.
  2. penetrate very slowly (requires several months).
  3. do not penetrate.
  4. penetrate fairly quickly (1 week to 1 month).

 

 

 

 

 

The answer is: D

 

16- Regarding the presence of bacteria, most studies show that the majority of periapical granulomas are:

  1. supportive of numbers of anaerobes primarily.
  2. supportive of numbers of anaerobes only, 
  3. supportive of numbers of variable, mixed flora.
  4. bacteria-free.

 

 

 

 

 

The answer is: D