Dental Hygiene NBDHE Exam Questions & Answers 2026 (11–20)

Question 1

Using the Miller index, tooth mobility classified as Class III indicates movement that is:

TheoryPractice · Accepted Answer

Horizontal more than 1 mm plus vertical (depressible) movement. Miller Class III is the most severe: horizontal movement exceeding 1 mm combined with the ability to depress the tooth in its socket (vertical mobility).

Question 2

Dental plaque is best described scientifically as which of the following?

TheoryPractice · Accepted Answer

A structured microbial biofilm. Plaque is a structured biofilm of microorganisms in an extracellular matrix; the acquired pellicle is the protein film that precedes bacterial colonization.

Question 3

Gingival recession is measured from which two landmarks?

TheoryPractice · Accepted Answer

Cementoenamel junction to free gingival margin. Recession is the distance from the CEJ to the gingival margin; adding it to the probing depth yields the total clinical attachment loss.

Question 4

A site has a probing depth of 4 mm and the gingival margin is located 2 mm apical to the CEJ. What is the clinical attachment loss at this site?

TheoryPractice · Accepted Answer

6 mm. When recession is present, CAL equals probing depth plus recession: 4 mm + 2 mm = 6 mm of attachment loss measured from the CEJ.

Question 5

A site shows a 5 mm probing depth, but the gingival margin sits 1 mm coronal to (above) the CEJ. What is the clinical attachment loss?

TheoryPractice · Accepted Answer

4 mm. When the margin is coronal to the CEJ, subtract that overgrowth: 5 mm probing depth minus 1 mm = 4 mm of true attachment loss.

Question 6

After active periodontal therapy, the typical recommended recall interval for periodontal maintenance is:

TheoryPractice · Accepted Answer

Every 3 to 4 months. A 3-to-4-month maintenance interval matches the time biofilm pathogens need to repopulate pockets, helping control recurrent disease.

Question 7

When sharpening a curet against a stationary flat stone, the recommended angle between the stone and the blade's face is about:

TheoryPractice · Accepted Answer

100 to 110 degrees. Holding the stone at roughly 100 to 110 degrees to the face preserves the correct internal blade angle (about 70 to 80 degrees) and a sharp cutting edge.

Question 8

Which patient situation is a traditional contraindication for using a magnetostrictive ultrasonic scaler?

TheoryPractice · Accepted Answer

An older non-shielded cardiac pacemaker. Older unshielded pacemakers could be affected by the electromagnetic field of magnetostrictive units; most modern pacemakers are shielded, but verifying the device is prudent.

Question 9

Radiographically, primary occlusal trauma most characteristically produces:

TheoryPractice · Accepted Answer

A widened periodontal ligament space. Excessive occlusal force widens the PDL space and may thicken the lamina dura without causing the attachment loss seen in periodontitis.

Question 10

Bleeding on probing is clinically significant primarily because it indicates:

TheoryPractice · Accepted Answer

Inflammation of the pocket lining. Bleeding on gentle probing signals ulceration and inflammation of the pocket epithelium and is a useful indicator of disease activity and tissue health.

Dental Hygiene NBDHE Exam Questions & Answers 2026 (11–20)

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