NBDHE Exam Actual Exam 2025 | National Board Dental
Hygiene Examination | Complete Questions and Correct
Answers with Explanations - 249 Questions
This exam assesses advanced competency in assessment and diagnosis for dental hygiene practice, including
clinical examination, risk assessment, radiography interpretation, and diagnostic decision-making for
comprehensive patient care. It contains 249 multiple-choice questions, each with four distractors and a fully
worked rationale that explains why the keyed answer is correct. Content is organized into 10 focused sections:
Assessment and Diagnosis, Periodontal Disease and Therapy, Dental Caries and Restorative Dentistry, Oral
Pathology and Radiology, Patient Management and Infection Control, Community Oral Health and Research,
Pharmacology and Pain Management, Nutrition and Preventive Dentistry, Ethics and Legal Issues, Special Needs
and Medical Emergencies. Targeted learning outcomes include: Accurately perform and interpret comprehensive
oral examinations.; Integrate radiographic findings with clinical data to formulate diagnoses.; Evaluate risk
factors and diagnostic tests to guide treatment planning.; Apply evidence-based criteria for assessment of
periodontal and caries diseases.. Every item has been reviewed for clinical accuracy, current guidelines, and
clarity so that students can study with confidence and self-correct as they work through the bank. Use it as a
high-yield review immediately before the exam, or as a structured practice tool during the unit - the rationales
double as concise teaching notes. The recommended writing time is 3 hours, with a passing score of 75%. Aligned
with CODA-accredited dental hygiene program; meets NBDHE 2025 standards. standards and reflects the
Section 1: Assessment and Diagnosis (Questions 1-25)
1 A patient presents with generalized gingival erythema, edema, and bleeding
on probing, but probing depths are 3 mm. Which assessment finding is most
critical to differentiate plaque-induced gingivitis from non-plaque-induced
gingival conditions?
A) Presence of pseudomembranes on the gingiva
B) Bleeding on probing at 50% of sites
C) Absence of clinical attachment loss
D) Localized distribution of erythema
Answer: C
Rationale: Absence of clinical attachment loss distinguishes gingivitis from
periodontitis. Plaque-induced gingivitis does not involve attachment loss,
whereas non-plaque-induced conditions may also lack attachment loss but have
distinct etiologies. Bleeding on probing is common in both. Pseudomembranes
suggest acute necrotizing ulcerative gingivitis. Localized distribution is not
diagnostic.
2 When assessing a patient with a history of recurrent aphthous ulcers, which
diagnostic feature most reliably indicates a major aphthous ulcer rather than
a minor one?
,A) Ulcer diameter >1 cm
B) Healing within 10-14 days
C) Presence of a prodromal burning sensation
D) Location on non-keratinized mucosa
Answer: A
Rationale: Major aphthous ulcers are larger (>1 cm), deeper, and heal with
scarring. Minor ulcers are <1 cm and heal without scarring. Prodromal burning
and location on non-keratinized mucosa are common to both types.
3 During an extraoral examination, you note a firm, fixed, non-tender lymph
node in the submandibular region. Which of the following is the most
appropriate next step?
A) Palpate the node bimanually to assess mobility
B) Refer the patient for immediate biopsy
C) Reassess in 2 weeks after treating any dental infection
D) Obtain a panoramic radiograph to evaluate the mandible
Answer: A
Rationale: A firm, fixed, non-tender node raises suspicion for malignancy.
Bimanual palpation helps assess mobility and consistency. Immediate biopsy is
not the first step; referral to a specialist for further evaluation is warranted.
Waiting 2 weeks or obtaining a radiograph without further assessment delays
diagnosis.
4 A patient with a history of bulimia nervosa presents with generalized dental
erosion. Which pattern of erosion is most consistent with this etiology?
A) Erosion primarily on occlusal surfaces of molars
B) Erosion on facial surfaces of maxillary anterior teeth
C) Erosion on lingual surfaces of maxillary anterior teeth
D) Erosion on incisal edges of mandibular incisors
Answer: C
Rationale: Bulimia nervosa causes frequent vomiting, exposing the lingual
surfaces of maxillary anterior teeth to gastric acid, leading to erosion. Facial
surfaces are more affected by extrinsic acids (e.g., citrus). Occlusal erosion is
typical of bruxism or dietary acids.
,5 Which of the following clinical findings is most indicative of a non-carious
cervical lesion (NCCL) caused by abfraction?
A) Shallow, saucer-shaped defect on the facial cervical area
B) Wedge-shaped defect with sharp margins at the cementoenamel junction
C) Wide, U-shaped groove on the root surface
D) Discolored, softened dentin at the gingival margin
Answer: B
Rationale: Abfraction lesions are wedge-shaped with sharp internal angles,
caused by biomechanical forces from occlusal loading. Abrasion produces
saucer-shaped defects, erosion causes U-shaped grooves, and caries leads to
softened, discolored dentin.
6 A patient has a probing depth of 6 mm on the mesial of tooth #19 with
bleeding on probing and suppuration. The radiograph shows vertical bone
loss of 4 mm from the CEJ. What is the clinical attachment loss (CAL)?
A) 2 mm
B) 4 mm
C) 6 mm
D) 10 mm
Answer: C
Rationale: CAL is calculated as probing depth (6 mm) minus gingival margin
position relative to CEJ. If the gingival margin is at the CEJ (no recession),
CAL equals probing depth. Since no recession is mentioned, CAL = 6 mm.
Option D incorrectly adds bone loss.
7 A panoramic radiograph reveals a well-defined, corticated radiolucency in
the mandibular premolar region associated with an impacted tooth. The
lesion is scalloped in outline. Which diagnosis is most likely?
A) Dentigerous cyst
B) Odontogenic keratocyst
C) Ameloblastoma
D) Residual cyst
Answer: B
Rationale: An odontogenic keratocyst (OKC) often presents as a well-defined,
corticated radiolucency with scalloped borders, frequently associated with an
impacted tooth. Dentigerous cysts surround the crown of an unerupted tooth
, but are not scalloped. Ameloblastoma is multilocular with a soap-bubble
appearance. Residual cysts occur after tooth extraction.
8 During periodontal probing, you encounter a site that bleeds profusely upon
gentle probing, with a probing depth of 5 mm and no visible inflammation.
The patient reports no pain. Which of the following is the most likely
explanation?
A) Acute periodontal abscess
B) Necrotizing ulcerative periodontitis
C) Systemic anticoagulant therapy
D) Aggressive periodontitis with localized attachment loss
Answer: C
Rationale: Profuse bleeding on probing without inflammation suggests a
bleeding diathesis, often due to anticoagulant therapy (e.g., warfarin). Acute
abscess and necrotizing disease present with pain and visible inflammation.
Aggressive periodontitis typically shows inflammation and attachment loss.
9 Which combination of findings is most consistent with a diagnosis of
chronic periodontitis (now classified as periodontitis Stage II, Grade B)?
A) Probing depths 4-5 mm, bleeding on probing, no attachment loss, plaque
present
B) Probing depths 5-6 mm, clinical attachment loss 3-4 mm, bleeding on
probing, smoking history
C) Probing depths 7 mm, clinical attachment loss 6 mm, suppuration,
furcation involvement
D) Probing depths 3 mm, clinical attachment loss 1 mm, no bleeding,
minimal plaque
Answer: B
Rationale: Chronic periodontitis (Stage II, Grade B) involves moderate probing
depths (5-6 mm), attachment loss (3-4 mm), bleeding, and risk factors like
smoking. Option A describes gingivitis (no attachment loss). Option C
represents severe periodontitis (Stage III/IV). Option D indicates health or
gingivitis.
Hygiene Examination | Complete Questions and Correct
Answers with Explanations - 249 Questions
This exam assesses advanced competency in assessment and diagnosis for dental hygiene practice, including
clinical examination, risk assessment, radiography interpretation, and diagnostic decision-making for
comprehensive patient care. It contains 249 multiple-choice questions, each with four distractors and a fully
worked rationale that explains why the keyed answer is correct. Content is organized into 10 focused sections:
Assessment and Diagnosis, Periodontal Disease and Therapy, Dental Caries and Restorative Dentistry, Oral
Pathology and Radiology, Patient Management and Infection Control, Community Oral Health and Research,
Pharmacology and Pain Management, Nutrition and Preventive Dentistry, Ethics and Legal Issues, Special Needs
and Medical Emergencies. Targeted learning outcomes include: Accurately perform and interpret comprehensive
oral examinations.; Integrate radiographic findings with clinical data to formulate diagnoses.; Evaluate risk
factors and diagnostic tests to guide treatment planning.; Apply evidence-based criteria for assessment of
periodontal and caries diseases.. Every item has been reviewed for clinical accuracy, current guidelines, and
clarity so that students can study with confidence and self-correct as they work through the bank. Use it as a
high-yield review immediately before the exam, or as a structured practice tool during the unit - the rationales
double as concise teaching notes. The recommended writing time is 3 hours, with a passing score of 75%. Aligned
with CODA-accredited dental hygiene program; meets NBDHE 2025 standards. standards and reflects the
Section 1: Assessment and Diagnosis (Questions 1-25)
1 A patient presents with generalized gingival erythema, edema, and bleeding
on probing, but probing depths are 3 mm. Which assessment finding is most
critical to differentiate plaque-induced gingivitis from non-plaque-induced
gingival conditions?
A) Presence of pseudomembranes on the gingiva
B) Bleeding on probing at 50% of sites
C) Absence of clinical attachment loss
D) Localized distribution of erythema
Answer: C
Rationale: Absence of clinical attachment loss distinguishes gingivitis from
periodontitis. Plaque-induced gingivitis does not involve attachment loss,
whereas non-plaque-induced conditions may also lack attachment loss but have
distinct etiologies. Bleeding on probing is common in both. Pseudomembranes
suggest acute necrotizing ulcerative gingivitis. Localized distribution is not
diagnostic.
2 When assessing a patient with a history of recurrent aphthous ulcers, which
diagnostic feature most reliably indicates a major aphthous ulcer rather than
a minor one?
,A) Ulcer diameter >1 cm
B) Healing within 10-14 days
C) Presence of a prodromal burning sensation
D) Location on non-keratinized mucosa
Answer: A
Rationale: Major aphthous ulcers are larger (>1 cm), deeper, and heal with
scarring. Minor ulcers are <1 cm and heal without scarring. Prodromal burning
and location on non-keratinized mucosa are common to both types.
3 During an extraoral examination, you note a firm, fixed, non-tender lymph
node in the submandibular region. Which of the following is the most
appropriate next step?
A) Palpate the node bimanually to assess mobility
B) Refer the patient for immediate biopsy
C) Reassess in 2 weeks after treating any dental infection
D) Obtain a panoramic radiograph to evaluate the mandible
Answer: A
Rationale: A firm, fixed, non-tender node raises suspicion for malignancy.
Bimanual palpation helps assess mobility and consistency. Immediate biopsy is
not the first step; referral to a specialist for further evaluation is warranted.
Waiting 2 weeks or obtaining a radiograph without further assessment delays
diagnosis.
4 A patient with a history of bulimia nervosa presents with generalized dental
erosion. Which pattern of erosion is most consistent with this etiology?
A) Erosion primarily on occlusal surfaces of molars
B) Erosion on facial surfaces of maxillary anterior teeth
C) Erosion on lingual surfaces of maxillary anterior teeth
D) Erosion on incisal edges of mandibular incisors
Answer: C
Rationale: Bulimia nervosa causes frequent vomiting, exposing the lingual
surfaces of maxillary anterior teeth to gastric acid, leading to erosion. Facial
surfaces are more affected by extrinsic acids (e.g., citrus). Occlusal erosion is
typical of bruxism or dietary acids.
,5 Which of the following clinical findings is most indicative of a non-carious
cervical lesion (NCCL) caused by abfraction?
A) Shallow, saucer-shaped defect on the facial cervical area
B) Wedge-shaped defect with sharp margins at the cementoenamel junction
C) Wide, U-shaped groove on the root surface
D) Discolored, softened dentin at the gingival margin
Answer: B
Rationale: Abfraction lesions are wedge-shaped with sharp internal angles,
caused by biomechanical forces from occlusal loading. Abrasion produces
saucer-shaped defects, erosion causes U-shaped grooves, and caries leads to
softened, discolored dentin.
6 A patient has a probing depth of 6 mm on the mesial of tooth #19 with
bleeding on probing and suppuration. The radiograph shows vertical bone
loss of 4 mm from the CEJ. What is the clinical attachment loss (CAL)?
A) 2 mm
B) 4 mm
C) 6 mm
D) 10 mm
Answer: C
Rationale: CAL is calculated as probing depth (6 mm) minus gingival margin
position relative to CEJ. If the gingival margin is at the CEJ (no recession),
CAL equals probing depth. Since no recession is mentioned, CAL = 6 mm.
Option D incorrectly adds bone loss.
7 A panoramic radiograph reveals a well-defined, corticated radiolucency in
the mandibular premolar region associated with an impacted tooth. The
lesion is scalloped in outline. Which diagnosis is most likely?
A) Dentigerous cyst
B) Odontogenic keratocyst
C) Ameloblastoma
D) Residual cyst
Answer: B
Rationale: An odontogenic keratocyst (OKC) often presents as a well-defined,
corticated radiolucency with scalloped borders, frequently associated with an
impacted tooth. Dentigerous cysts surround the crown of an unerupted tooth
, but are not scalloped. Ameloblastoma is multilocular with a soap-bubble
appearance. Residual cysts occur after tooth extraction.
8 During periodontal probing, you encounter a site that bleeds profusely upon
gentle probing, with a probing depth of 5 mm and no visible inflammation.
The patient reports no pain. Which of the following is the most likely
explanation?
A) Acute periodontal abscess
B) Necrotizing ulcerative periodontitis
C) Systemic anticoagulant therapy
D) Aggressive periodontitis with localized attachment loss
Answer: C
Rationale: Profuse bleeding on probing without inflammation suggests a
bleeding diathesis, often due to anticoagulant therapy (e.g., warfarin). Acute
abscess and necrotizing disease present with pain and visible inflammation.
Aggressive periodontitis typically shows inflammation and attachment loss.
9 Which combination of findings is most consistent with a diagnosis of
chronic periodontitis (now classified as periodontitis Stage II, Grade B)?
A) Probing depths 4-5 mm, bleeding on probing, no attachment loss, plaque
present
B) Probing depths 5-6 mm, clinical attachment loss 3-4 mm, bleeding on
probing, smoking history
C) Probing depths 7 mm, clinical attachment loss 6 mm, suppuration,
furcation involvement
D) Probing depths 3 mm, clinical attachment loss 1 mm, no bleeding,
minimal plaque
Answer: B
Rationale: Chronic periodontitis (Stage II, Grade B) involves moderate probing
depths (5-6 mm), attachment loss (3-4 mm), bleeding, and risk factors like
smoking. Option A describes gingivitis (no attachment loss). Option C
represents severe periodontitis (Stage III/IV). Option D indicates health or
gingivitis.
