NBDHE Cheat Sheet 2026

The 30 highest-yield NBDHE facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. What class of dental product includes Listerine and Scope? → Mouthwash
2. A periapical radiograph showing a well-defined radiolucency with a sclerotic border at the apex of a vital tooth is MOST likely: → Periapical cemento-osseous dysplasia (early stage)
3. Which component of the periodontal ligament (PDL) inserts into cementum on the tooth side and alveolar bone on the other? → Sharpey's fibers
4. Secondary prevention in dentistry is best illustrated by: → Early detection and treatment of incipient gingivitis
5. A patient with chronic obstructive pulmonary disease (COPD) requires dental hygiene treatment. Which modification is most important? → Positioning the patient semi-upright and minimizing use of water spray near the airway
6. A dental hygienist receives a subpoena for a patient's dental records. The most appropriate response is to: → Consult with the practice's legal counsel and follow proper legal procedures
7. A 7-year-old patient has an unerupted permanent maxillary central incisor 18 months after the contralateral incisor erupted. What is the most likely cause? → Supernumerary tooth (mesiodens)
8. The Bass toothbrushing technique is most effective at removing plaque from: → The gingival sulcus and margin
9. What is the PURPOSE of an external chemical indicator (Type 1 process indicator) placed on a sterilization package? → Confirms that the package was exposed to the sterilization process
10. In Glickman's classification of furcation involvement, a Class II furcation is best described as a defect in which: → The probe enters the furcation but does not pass through to the opposite side
11. Erythroplakia is clinically significant because it has a higher malignant transformation rate than which lesion? → Leukoplakia
12. Which oral lesion appears as a white, non-removable plaque on the oral mucosa that cannot be attributed to any other known disease? → Leukoplakia
13. Which item is classified as 'semicritical' in the Spaulding classification system? → Reusable impression tray
14. During active periodontal debridement with a hand curette, the correct working angulation of the blade face against the tooth surface is: → 45 to 90 degrees
15. Which radiograph provides the best detail for evaluating interproximal alveolar bone levels? → Bitewing radiograph
16. Kaposi's sarcoma in the oral cavity appears most frequently on which structure? → Hard palate and gingiva
17. A patient asks how long they should brush their teeth. The evidence-based recommendation for toothbrushing time is: → 2 minutes
18. Who served as the first president of the American Dental Hygienists' Association upon its founding? → Gillette Hayden
19. Necrotizing ulcerative gingivitis (NUG) is characterized by which classic triad of findings? → Interdental papilla necrosis, pain, and fetid odor
20. Which of the following systemic conditions is most associated with hypercementosis and hypoplastic enamel in primary teeth? → Vitamin D-resistant rickets (X-linked hypophosphatemia)
21. What does the acronym 'ADHA Standards of Clinical Dental Hygiene Practice' include as the five components of the dental hygiene process? → Assessment, Dental Hygiene Diagnosis, Planning, Implementation, and Evaluation
22. The Oral Hygiene Index-Simplified (OHI-S), developed by Greene and Vermillion, is calculated by combining scores from which two sub-indices? → Debris Index and Calculus Index
23. Which form of supervision requires the dentist to be physically present in the office while a dental hygienist performs a procedure? → Direct supervision
24. Fluoride can be found in what sources? → Water
25. OSHA's Bloodborne Pathogens Standard requires employers to offer hepatitis B vaccination to: → Employees with potential occupational exposure to blood or OPIM
26. Which U.S. state was the first to legally license dental hygienists, doing so in 1917? → Connecticut
27. The primary purpose of the lead apron with thyroid collar in dental radiography is to: → Protect radiosensitive tissues — gonads and thyroid — from scatter radiation
28. When calculating the sensitivity of a diagnostic test for periodontitis, which value represents the percentage of people WITH the disease who test positive? → True positive / (True positive + False negative) × 100
29. A patient has a 6 mm periodontal pocket on the mesial of tooth #14 with bleeding on probing. Which instrument is most appropriate for debridement in this area? → Gracey 11/12 curette
30. When treating an elderly patient with dementia, which legal and ethical principle is most important before beginning treatment? → Verifying that informed consent is obtained from the legal guardian or healthcare proxy