INBDE Microbiology & Immunology practice questions

Question 1

A 9-year-old patient presents with several incipient 'white spot' lesions on the smooth surfaces of his permanent first molars. Which of the following microorganisms is most likely responsible for the initiation of these lesions through the production of extracellular glucans?

Accepted Answer

Streptococcus mutans

Answer

Lactobacillus acidophilus

Answer

Actinomyces viscosus

Answer

Streptococcus salivarius

Question 2

A 45-year-old male with generalized Stage III, Grade B periodontitis undergoes a microbial analysis of his subgingival plaque. Which of the following trios of bacteria, known as the 'Red Complex,' are most likely to be found in high concentrations in his deep periodontal pockets?

Accepted Answer

Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia

Answer

Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Eikenella corrodens

Answer

Fusobacterium nucleatum, Prevotella intermedia, Campylobacter rectus

Answer

Streptococcus sanguinis, Actinomyces naeslundii, Veillonella parvula

Question 3

During the formation of dental plaque biofilm, which of the following describes the correct order of microbial succession on a clean tooth surface?

Accepted Answer

Gram-positive cocci → Gram-positive rods and filaments → Gram-negative anaerobes

Answer

Gram-negative anaerobes → Gram-positive cocci → Filamentous bacteria

Answer

Spirochetes → Gram-negative rods → Gram-positive cocci

Answer

Lactobacilli → Streptococci → Actinomyces

Question 4

Immediately following the administration of local anesthesia with 2% lidocaine and 1:100,000 epinephrine, a patient develops generalized urticaria, wheezing, and hypotension. This clinical presentation most likely represents which type of hypersensitivity reaction?

Accepted Answer

Type I (Immediate)

Answer

Type II (Cytotoxic)

Answer

Type III (Immune complex)

Answer

Type IV (Delayed-type)

Question 5

A 14-year-old female presents with rapid bone loss around her permanent maxillary first molars and mandibular incisors, with very little visible plaque or inflammation. Which virulence factor produced by Aggregatibacter actinomycetemcomitans is primarily responsible for destroying host polymorphonuclear leukocytes (PMNs)?

Accepted Answer

Leukotoxin

Answer

Gingipain proteases

Answer

Hyaluronidase

Answer

Dextranase

Question 6

A patient presents with multiple painful vesicles and ulcers distributed on the hard palate and the attached gingiva. He reports having similar outbreaks in the same locations in the past. What is the most likely diagnosis?

Accepted Answer

Recurrent intraoral herpes simplex

Answer

Minor aphthous stomatitis

Answer

Primary herpetic gingivostomatitis

Answer

Recurrent herpes labialis

Question 7

Which of the following biological indicators is used to verify the effectiveness of a steam autoclave in a dental office?

Accepted Answer

Geobacillus stearothermophilus

Answer

Mycobacterium tuberculosis

Answer

Bacillus atrophaeus

Answer

Clostridium difficile

Question 8

A 62-year-old patient taking broad-spectrum antibiotics for a respiratory infection develops a white, curd-like coating on the buccal mucosa that can be easily wiped away with gauze, leaving an erythematous base. Which organism is the most likely causative agent?

Accepted Answer

Candida albicans

Answer

Epstein-Barr virus

Answer

Human papillomavirus

Answer

Corynebacterium diphtheriae

Question 9

Which class of immunoglobulin is found in the highest concentration in saliva and provides the primary mucosal defense against oral pathogens?

Accepted Answer

Secretory IgA

Answer

IgG

Answer

IgM

Answer

IgE

Question 10

A patient with a history of penicillin allergy is accidentally prescribed amoxicillin. Within 30 minutes, they develop laryngeal edema and difficulty breathing. Which of the following is the mediator for this reaction?

Accepted Answer

IgE-mediated mast cell degranulation

Answer

T-lymphocytes

Answer

IgG-mediated cytotoxic lysis

Answer

Immune complex deposition in blood vessels

INBDE Microbiology & Immunology practice questions

A 9-year-old patient presents with several incipient 'white spot' lesions on the smooth surfaces of his permanent first molars. Which of the following microorganisms is most likely responsible for the initiation of these lesions through the production of extracellular glucans?

A 45-year-old male with generalized Stage III, Grade B periodontitis undergoes a microbial analysis of his subgingival plaque. Which of the following trios of bacteria, known as the 'Red Complex,' are most likely to be found in high concentrations in his deep periodontal pockets?

During the formation of dental plaque biofilm, which of the following describes the correct order of microbial succession on a clean tooth surface?

Immediately following the administration of local anesthesia with 2% lidocaine and 1:100,000 epinephrine, a patient develops generalized urticaria, wheezing, and hypotension. This clinical presentation most likely represents which type of hypersensitivity reaction?

A patient presents with multiple painful vesicles and ulcers distributed on the hard palate and the attached gingiva. He reports having similar outbreaks in the same locations in the past. What is the most likely diagnosis?

Which of the following biological indicators is used to verify the effectiveness of a steam autoclave in a dental office?

A 62-year-old patient taking broad-spectrum antibiotics for a respiratory infection develops a white, curd-like coating on the buccal mucosa that can be easily wiped away with gauze, leaving an erythematous base. Which organism is the most likely causative agent?

Which class of immunoglobulin is found in the highest concentration in saliva and provides the primary mucosal defense against oral pathogens?

A patient with a history of penicillin allergy is accidentally prescribed amoxicillin. Within 30 minutes, they develop laryngeal edema and difficulty breathing. Which of the following is the mediator for this reaction?

The first 10 are free. 5 more below.

Lactobacillus species are frequently isolated from deep carious lesions. Which physiological property allows them to thrive in this environment and contribute to the progression of decay?

A dental assistant develops a pruritic, erythematous, vesicular rash on the dorsal surface of her hands 48 hours after wearing latex gloves. This reaction is most likely a:

Porphyromonas gingivalis, a key periodontal pathogen, is a Gram-negative obligate anaerobe. Which component of its cell wall is particularly responsible for triggering the release of pro-inflammatory cytokines like IL-1 and TNF-alpha from host macrophages?

A 3-year-old child presents with high fever, lymphadenopathy, and painful, erythematous, swollen gingiva with diffuse small ulcers across both the keratinized and non-keratinized mucosa. What is the most likely diagnosis?

Regarding infection control, which of the following is the correct definition of 'Disinfection' compared to 'Sterilization'?