NBDHE Dental Hygiene MCQ 2 — Questions and Answers

Question 1: Dental plaque is best defined as:

A structured, microbially diverse biofilm that adheres to tooth surfaces and soft tissues and resists removal by rinsing (Correct answer)
Loose food debris that accumulates between teeth
Calcified mineral deposits on the root surface
A transient film of salivary proteins without bacteria

Correct answer: A structured, microbially diverse biofilm that adheres to tooth surfaces and soft tissues and resists removal by rinsing

Dental plaque is a complex, organized biofilm community embedded in an extracellular matrix that adheres firmly to tooth surfaces and cannot be removed by rinsing — only mechanical disruption.

Plaque biofilm develops in a sequential colonization process: (1) Pellicle formation — salivary glycoproteins adsorb to the clean enamel surface within seconds; (2) Primary colonizers — S. sanguis, S. mitis, Actinomyces attach to pellicle proteins within hours; (3) Secondary colonizers — F. nucleatum acts as a bridge organism; (4) Late colonizers — anaerobic species including red complex organisms colonize established biofilm. The biofilm's extracellular polymeric substance (EPS) — predominantly glucans produced by GTF enzymes — provides structural integrity, nutrient channels, and resistance to antibiotics and host defenses. Biofilm bacteria are up to 1,000× more resistant to antimicrobials than planktonic (free-floating) bacteria. Mechanical disruption (brushing/flossing/scaling) remains the primary means of plaque control.

Question 2: The role of the dental hygienist during a medical emergency in the dental office is to:

Provide basic life support (BLS), assist the dentist, call emergency services (911), and manage the emergency within their training until EMS arrives (Correct answer)
Step aside and let only the dentist manage all emergencies
Administer all emergency medications without dentist guidance
Only record what happened and call the patient's physician

Correct answer: Provide basic life support (BLS), assist the dentist, call emergency services (911), and manage the emergency within their training until EMS arrives

All dental team members must be trained in BLS/CPR; the DH activates EMS, assists with emergency medications, performs CPR, uses the AED, and supports the dentist throughout the emergency.

Dental offices must have emergency protocols, equipment, and trained staff: (1) Recognize the emergency and activate EMS (call 911) — the most critical early action; (2) Basic life support — all dental staff must have current CPR/AED certification (AHA BLS for Healthcare Providers); (3) Emergency drugs (required: oxygen, epinephrine 1:1000 IM for anaphylaxis, nitroglycerin for angina, albuterol inhaler for bronchospasm, 50% dextrose/oral glucose for hypoglycemia, aspirin for suspected MI, diphenhydramine for mild allergic reactions); (4) The dental hygienist should know their role in the office emergency protocol — typically: monitor vitals, assist drug administration, operate AED, perform CPR; (5) Documentation of the event for medical-legal purposes.

Question 3: Which surface of teeth shows the highest plaque scores in patients who are not motivated to practice oral hygiene?

Interproximal (proximal) surfaces and the gingival margin on all surfaces (Correct answer)
Occlusal pits and fissures
Smooth buccal surfaces at the height of contour
Cusp tips and incisal edges

Correct answer: Interproximal (proximal) surfaces and the gingival margin on all surfaces

Interproximal surfaces and areas near the gingival margin accumulate the most plaque because toothbrush bristles have limited access — these are also the most common sites for both caries and periodontal disease initiation.

Plaque retention is influenced by: (1) Tooth morphology — interproximal surfaces, line angles, fissures, furcations; (2) Restorations — overhanging margins create plaque traps; (3) Crowding — reduced access for hygiene aids; (4) Saliva flow — areas of reduced salivary clearance (mandibular anterior lingual surfaces near Wharton's duct opening are exceptions — natural cleaning). In clinical practice, plaque indices (O'Leary Plaque Index, Löe-Silness Plaque Index) typically record the gingival third of all four surfaces (mesial, distal, buccal, lingual) as this is where pathogenic subgingival biofilm initiates. Disclosing agents (erythrosine, 2-tone solution) reveal plaque distribution for patient education and motivation.

Question 4: Periodontal probing should be performed at how many sites per tooth for a comprehensive periodontal assessment?

6 sites — mesiobuccal, midbuccal, distobuccal, mesiolingual, midlingual, distolingual (Correct answer)
4 sites only — one per corner
1 site per tooth — deepest point only
2 sites — buccal and lingual only

Correct answer: 6 sites — mesiobuccal, midbuccal, distobuccal, mesiolingual, midlingual, distolingual

A full-mouth periodontal chart records 6 sites per tooth (mesiobuccal, buccal, distobuccal, distolingual, lingual, mesiolingual), providing comprehensive assessment of pocket depth and attachment level distribution.

The standard full-mouth periodontal assessment (per ADA/AAP guidelines) records at least 6 probing depth measurements per tooth: mesiobuccal (MB), midbuccal (B), distobuccal (DB), distolingual (DL), midlingual (L), mesiolingual (ML). Additional readings per site: (1) Gingival margin level (to calculate CAL); (2) Bleeding on probing (BOP) — present/absent; (3) Suppuration; (4) Furcation involvement; (5) Tooth mobility; (6) Recession; (7) Mucogingival findings. A complete chart provides 168 probing depth readings for a full dentition (28 teeth × 6 sites). Partial or spot-check charting is insufficient for accurate disease staging and treatment planning. Electronic probing systems (Florida Probe) improve reproducibility.

Question 5: Which of the following is considered a modifiable risk factor for periodontal disease?

Cigarette smoking (Correct answer)
Age
Genetic predisposition
Male sex

Correct answer: Cigarette smoking

Cigarette smoking is the strongest modifiable risk factor for periodontal disease; smokers have 2–7× higher risk and worse treatment outcomes than non-smokers, but cessation improves periodontal prognosis.

Risk factors for periodontal disease: Non-modifiable — age (disease prevalence increases with age), genetic factors (IL-1 polymorphisms, complement deficiencies), sex (males slightly higher prevalence). Modifiable — smoking (strongest: 2–7× risk, impairs neutrophil function, vasoconstriction masks BOP, promotes anaerobic subgingival environment), diabetes mellitus (modifiable if glycemic control improved), obesity, stress (cortisol-mediated immune suppression), medications (Ca channel blockers, phenytoin), plaque/calculus (the etiologic agent). Tobacco cessation is the single most impactful behavior change for improving periodontal outcomes. Dental hygienists should provide the 5 A's framework (Ask, Advise, Assess, Assist, Arrange) for tobacco cessation counseling at every visit.

Question 6: The term 'ergonomics' in dental hygiene practice refers to:

The science of designing the work environment and work practices to minimize physical stress and reduce the risk of musculoskeletal injuries in the clinician (Correct answer)
A technique for patient positioning during treatment
The study of instrument metallurgy and sharpening
The management of radiation doses in radiography

Correct answer: The science of designing the work environment and work practices to minimize physical stress and reduce the risk of musculoskeletal injuries in the clinician

Ergonomics applies biomechanical principles to the clinical workspace to reduce musculoskeletal disorders (MSDs) — the leading occupational health concern for dental hygienists.

Musculoskeletal disorders (MSDs) affect up to 96% of dental hygienists at some point in their careers, primarily affecting the neck, shoulder, wrist/hand (carpal tunnel syndrome), and back. Risk factors: sustained awkward postures, static loading, forceful exertions, vibration, contact stress, and repetitive motion. Ergonomic interventions: (1) Neutral operator posture — head upright, shoulders relaxed, forearms parallel to floor, feet flat; (2) Proper patient chair positioning — reduce clinician bending; (3) Ergonomic instrument design — silicone handles, balanced weight, appropriate diameter; (4) Magnification loupes — improve vision without neck flexion; (5) Ultrasonic over hand scaling — reduces force requirements; (6) Stretch breaks and exercise; (7) Varied appointment scheduling. OSHA does not have a specific ergonomics standard for dentistry but general duty clause applies.

NBDHE Dental Hygiene MCQ 2

Dental plaque is best defined as: