Dental Hygiene NBDHE Exam Questions & Answers 2026 (1–10)

Question 1

In a healthy adult, what is the typical depth of the gingival sulcus measured with a periodontal probe?

TheoryPractice · Accepted Answer

1 to 3 millimeters. A clinically healthy sulcus measures roughly 1 to 3 mm. Readings of 4 mm or more usually indicate attachment loss or a pseudopocket and warrant further evaluation.

Question 2

Which group of periodontal ligament fibers chiefly resists vertical (intrusive) occlusal forces by suspending the tooth in its socket?

TheoryPractice · Accepted Answer

Oblique fibers. Oblique fibers are the most numerous PDL group and run coronally from bone to apically on the cementum, resisting masticatory forces that tend to push the tooth into its socket.

Question 3

Under the 2017 AAP/EFP classification, a patient with 5 mm clinical attachment loss, probing depths of 6 mm, and bone loss extending to the middle third of the root is best staged as which periodontitis stage?

TheoryPractice · Accepted Answer

Stage III. Interdental CAL of 5 mm or more and radiographic bone loss reaching the mid-third of the root place the case in Stage III, which also carries potential for tooth loss without intervention.

Question 4

Subgingival calculus most commonly appears which color when detected clinically?

TheoryPractice · Accepted Answer

Dark brown or black. Subgingival calculus is darkened (brown to black) by blood pigments from inflamed pocket tissue, in contrast to the white-to-yellow supragingival calculus.

Question 5

When adapting a Gracey curet for subgingival scaling, what is the correct working-end angulation of the blade face to the tooth surface?

TheoryPractice · Accepted Answer

Between 45 and 90 degrees. An angulation between 45 and 90 degrees lets the cutting edge engage and remove the deposit; angles below 45 degrees burnish calculus and angles near 90 degrees can gouge.

Question 6

A Gracey 13/14 curet is specifically designed to instrument which surfaces?

TheoryPractice · Accepted Answer

Posterior distal surfaces. Gracey curets are area-specific: 13/14 is angled for distal surfaces of posterior teeth, while 11/12 is for mesial posterior surfaces.

Question 7

Which inflammatory mediator most directly stimulates osteoclastic alveolar bone resorption in periodontitis?

TheoryPractice · Accepted Answer

Prostaglandin E2. Prostaglandin E2, along with IL-1 and TNF-alpha, upregulates the RANKL pathway driving osteoclast activity and bone loss; IL-10 is anti-inflammatory.

Question 8

Which bacterium of the 'red complex' is most strongly associated with chronic periodontitis?

TheoryPractice · Accepted Answer

Porphyromonas gingivalis. Porphyromonas gingivalis, a Gram-negative anaerobe of the red complex, is a key periodontal pathogen; S. mutans and Lactobacillus are caries-related.

Question 9

The classic clinical triad of necrotizing ulcerative gingivitis (NUG) is pain, gingival bleeding, and which third sign?

TheoryPractice · Accepted Answer

Punched-out, cratered interdental papillae. NUG presents with necrosis producing punched-out, cratered papillae often covered by a gray pseudomembrane, accompanied by spontaneous bleeding and marked pain.

Question 10

A Nabers probe is the instrument of choice for assessing what periodontal finding?

TheoryPractice · Accepted Answer

Furcation involvement. The curved Nabers probe is designed to detect and grade horizontal furcation involvement on multirooted teeth.

Dental Hygiene NBDHE Exam Questions & Answers 2026 (1–10)

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