NBDHE Pharmacology in Dental Hygiene 3

Question 1

What is the mechanism of action of metronidazole, and why is it effective against periodontal pathogens?

Accepted Answer

It is a prodrug activated in anaerobic organisms to form nitro radical anions that disrupt DNA, making it bactericidal against anaerobes including Porphyromonas gingivalis

Answer

Metronidazole is reduced by ferredoxin under anaerobic conditions to form toxic radical intermediates that cause DNA strand breaks, making it selectively lethal to strict anaerobes like major periodontal pathogens.

Question 2

Which locally delivered controlled-release antibiotic device is FDA-approved for adjunctive use in periodontal pockets ≥5 mm?

Accepted Answer

Doxycycline hyclate 10% polymer gel (Atridox) and minocycline microspheres (Arestin)

Answer

Atridox (doxycycline 10% polymer gel) and Arestin (minocycline microspheres 1 mg) are the primary FDA-approved locally delivered antibiotic systems for adjunctive subgingival use in periodontal pockets.

Question 3

A patient reports severe anxiety about dental treatment and requests 'something to calm them down.' The drug diazepam (Valium) belongs to which drug class, and what is its mechanism of action?

Accepted Answer

Benzodiazepine — positive allosteric modulator of GABA-A receptors, increasing chloride ion conductance and producing CNS depression

Answer

Diazepam is a benzodiazepine that enhances GABA-A receptor activity by binding at the benzodiazepine site, increasing the frequency of chloride channel opening, hyperpolarizing neurons, and producing anxiolysis and sedation.

Question 4

Which drug interaction is MOST critical for a dental hygienist to recognize when a patient is taking monoamine oxidase inhibitors (MAOIs) for depression?

Accepted Answer

MAOIs can cause hypertensive crisis if combined with indirectly-acting sympathomimetic agents, and dangerous serotonin syndrome if combined with meperidine

Answer

MAO inhibitors prevent breakdown of catecholamines and serotonin; indirect sympathomimetics can cause severe hypertensive crisis, and meperidine (Demerol) can trigger fatal serotonin syndrome.

Question 5

Fluoride works to prevent dental caries through which primary mechanism at the tooth surface?

Accepted Answer

Incorporation into hydroxyapatite to form fluorapatite, which is more acid-resistant, and promotion of remineralization during pH cycling

Answer

Fluoride's primary anticaries mechanism is ionic substitution in hydroxyapatite crystals to form fluorapatite (FAP), which has a higher critical pH, making enamel less susceptible to acid dissolution and facilitating remineralization.

NBDHE Test Practice Test

NBDHE Test Practice Test

NBDHE Pharmacology in Dental Hygiene 3