NBDHE Test Pharmacology in Dental Hygiene 1 — Questions and Answers
Question 1: According to the American Heart Association guidelines, what is the recommended first-line antibiotic for prophylaxis against infective endocarditis prior to dental procedures in at-risk patients who can take oral medications?
- Clindamycin 600 mg
- Amoxicillin 2 g (Correct answer)
- Azithromycin 500 mg
- Doxycycline 100 mg
Correct answer: Amoxicillin 2 g
Amoxicillin 2 g orally 30–60 minutes before the procedure is the AHA first-line recommendation because it achieves high, sustained serum levels and is well absorbed. Clindamycin was removed from the AHA guidelines in 2021 due to risk of Clostridioides difficile colitis.
Question 2: A patient taking propranolol (a non-selective beta-blocker) receives 2 carpules of 2% lidocaine with 1:100,000 epinephrine. What is the PRIMARY cardiovascular concern?
- Hypotension from additive vasodilation
- Hypertensive crisis from unopposed alpha-adrenergic stimulation (Correct answer)
- Reflex tachycardia from epinephrine
- Complete heart block from lidocaine toxicity
Correct answer: Hypertensive crisis from unopposed alpha-adrenergic stimulation
Non-selective beta-blockers block beta-2 (vasodilatory) receptors while leaving alpha-1 (vasoconstrictive) receptors unblocked. Epinephrine then causes unopposed alpha-1 stimulation, leading to a sharp rise in blood pressure and a reflex bradycardia — potentially a hypertensive crisis.
Question 3: Tetracycline and its derivatives are contraindicated in children under age 8 primarily because they cause:
- Gingival hyperplasia and delayed eruption
- Permanent intrinsic discoloration of developing teeth (Correct answer)
- Enamel hypoplasia limited to primary dentition
- Increased susceptibility to early childhood caries
Correct answer: Permanent intrinsic discoloration of developing teeth
Tetracyclines chelate calcium ions and are incorporated into mineralizing tooth structure, producing permanent yellow-gray-brown intrinsic staining in teeth that are still developing (up to approximately age 8). This affects both primary and permanent dentition depending on the child's age.
Question 4: A patient prescribed metronidazole (Flagyl) for a periodontal infection asks what to avoid while taking the medication. Which of the following is MOST important to counsel?
- Dairy products, which reduce absorption
- Alcohol, which can cause a disulfiram-like reaction (Correct answer)
- Grapefruit juice, which inhibits metabolism
- Antacids, which chelate the drug
Correct answer: Alcohol, which can cause a disulfiram-like reaction
Metronidazole inhibits acetaldehyde dehydrogenase, the same enzyme blocked by disulfiram (Antabuse). If a patient consumes alcohol, acetaldehyde accumulates, causing flushing, nausea, vomiting, and palpitations. Patients must avoid all alcohol — including mouthrinses — during and for 48 hours after therapy.
Question 5: A 65-year-old patient has been taking oral alendronate (Fosamax) for osteoporosis for seven years. She requires extraction of a non-restorable molar. The dental hygienist should be aware that her GREATEST drug-related risk is:
- Prolonged bleeding due to antiplatelet effects
- Medication-related osteonecrosis of the jaw (MRONJ) (Correct answer)
- Impaired healing from immunosuppression
- Increased risk of dry socket from vasoconstriction
Correct answer: Medication-related osteonecrosis of the jaw (MRONJ)
Bisphosphonates are incorporated into bone and suppress osteoclast activity, impairing the bone remodeling necessary for healing after invasive procedures. Long-term oral bisphosphonate use — especially over three years — significantly raises the risk of MRONJ, particularly following tooth extraction or other dento-alveolar surgery.
Question 6: Which drug class is MOST commonly responsible for medication-induced xerostomia seen in dental hygiene patients?
- Penicillin-class antibiotics
- Anticholinergic agents (including tricyclic antidepressants and antihistamines) (Correct answer)
- ACE inhibitors
- Fluoroquinolone antibiotics
Correct answer: Anticholinergic agents (including tricyclic antidepressants and antihistamines)
Anticholinergic drugs block muscarinic receptors on salivary glands, directly reducing salivary secretion. This class includes tricyclic antidepressants, first-generation antihistamines, antispasmodics, and many antipsychotics — making anticholinergic side effects a leading cause of dry mouth and its sequelae (caries, candidiasis, dysphagia) in dental patients.
NBDHE Test Pharmacology in Dental Hygiene 1
According to the American Heart Association guidelines, what is the recommended first-line antibiotic for prophylaxis against infective endocarditis prior to dental procedures in at-risk patients who can take oral medications?