Integrated National Board Dental
Examination (INBDE) Comprehensive
Practice Examination 2026–2027 |
Comprehensive Question Practice Test
with Answers & Rationales| Free Pdf
Access
1. A 24-year-old patient presents with bleeding gums during brushing. Which condition
is the most likely cause?
A. Gingivitis
B. Amelogenesis imperfecta
C. Oral candidiasis
D. Leukoplakia
Correct Answer: A
Rationale: Gingivitis is characterized by inflammation of the gingiva, often presenting with
bleeding during brushing or flossing. It is commonly caused by plaque accumulation and
is reversible with proper oral hygiene.
2. Which microorganism is most strongly associated with the initiation of dental caries?
A. Streptococcus mutans
B. Candida albicans
C. Actinomyces israelii
D. Porphyromonas gingivalis
Correct Answer: A
,Rationale: Streptococcus mutans metabolizes dietary carbohydrates into acids that
demineralize enamel and initiate caries formation.
3. The primary inorganic component of enamel is:
A. Hydroxyapatite
B. Collagen
C. Keratin
D. Elastin
Correct Answer: A
Rationale: Enamel consists primarily of hydroxyapatite crystals, providing strength and
resistance to wear.
4. Which cranial nerve provides motor innervation to the muscles of mastication?
A. Facial nerve (CN VII)
B. Trigeminal nerve (CN V3)
C. Glossopharyngeal nerve (CN IX)
D. Hypoglossal nerve (CN XII)
Correct Answer: B
Rationale: The mandibular division of the trigeminal nerve supplies the muscles
responsible for chewing.
5. A patient reports sensitivity to cold after placement of a deep composite restoration.
The most likely explanation is:
A. Reversible pulpitis
B. Irreversible pulpitis
C. Pulp necrosis
D. Periapical abscess
Correct Answer: A
Rationale: Mild sensitivity to thermal stimuli after restorative treatment often indicates
reversible pulpitis, which may resolve as the pulp heals.
6. Which type of tooth is best adapted for tearing food?
, A. Incisor
B. Canine
C. Premolar
D. Molar
Correct Answer: B
Rationale: Canines possess pointed cusps designed for tearing and grasping food.
7. The permanent dentition normally contains how many teeth?
A. 20
B. 24
C. 28
D. 32
Correct Answer: D
Rationale: The complete adult dentition consists of 32 teeth, including third molars.
8. Which salivary gland produces the largest volume of saliva?
A. Sublingual gland
B. Parotid gland
C. Minor salivary glands
D. Palatine gland
Correct Answer: B
Rationale: The parotid glands are the largest salivary glands and contribute significantly to
stimulated salivary flow.
9. Which oral lesion has the highest potential for malignant transformation?
A. Aphthous ulcer
B. Mucocele
C. Leukoplakia with dysplasia
D. Traumatic fibroma
Correct Answer: C
Rationale: Dysplastic leukoplakia is considered a potentially malignant disorder requiring
close evaluation.
Examination (INBDE) Comprehensive
Practice Examination 2026–2027 |
Comprehensive Question Practice Test
with Answers & Rationales| Free Pdf
Access
1. A 24-year-old patient presents with bleeding gums during brushing. Which condition
is the most likely cause?
A. Gingivitis
B. Amelogenesis imperfecta
C. Oral candidiasis
D. Leukoplakia
Correct Answer: A
Rationale: Gingivitis is characterized by inflammation of the gingiva, often presenting with
bleeding during brushing or flossing. It is commonly caused by plaque accumulation and
is reversible with proper oral hygiene.
2. Which microorganism is most strongly associated with the initiation of dental caries?
A. Streptococcus mutans
B. Candida albicans
C. Actinomyces israelii
D. Porphyromonas gingivalis
Correct Answer: A
,Rationale: Streptococcus mutans metabolizes dietary carbohydrates into acids that
demineralize enamel and initiate caries formation.
3. The primary inorganic component of enamel is:
A. Hydroxyapatite
B. Collagen
C. Keratin
D. Elastin
Correct Answer: A
Rationale: Enamel consists primarily of hydroxyapatite crystals, providing strength and
resistance to wear.
4. Which cranial nerve provides motor innervation to the muscles of mastication?
A. Facial nerve (CN VII)
B. Trigeminal nerve (CN V3)
C. Glossopharyngeal nerve (CN IX)
D. Hypoglossal nerve (CN XII)
Correct Answer: B
Rationale: The mandibular division of the trigeminal nerve supplies the muscles
responsible for chewing.
5. A patient reports sensitivity to cold after placement of a deep composite restoration.
The most likely explanation is:
A. Reversible pulpitis
B. Irreversible pulpitis
C. Pulp necrosis
D. Periapical abscess
Correct Answer: A
Rationale: Mild sensitivity to thermal stimuli after restorative treatment often indicates
reversible pulpitis, which may resolve as the pulp heals.
6. Which type of tooth is best adapted for tearing food?
, A. Incisor
B. Canine
C. Premolar
D. Molar
Correct Answer: B
Rationale: Canines possess pointed cusps designed for tearing and grasping food.
7. The permanent dentition normally contains how many teeth?
A. 20
B. 24
C. 28
D. 32
Correct Answer: D
Rationale: The complete adult dentition consists of 32 teeth, including third molars.
8. Which salivary gland produces the largest volume of saliva?
A. Sublingual gland
B. Parotid gland
C. Minor salivary glands
D. Palatine gland
Correct Answer: B
Rationale: The parotid glands are the largest salivary glands and contribute significantly to
stimulated salivary flow.
9. Which oral lesion has the highest potential for malignant transformation?
A. Aphthous ulcer
B. Mucocele
C. Leukoplakia with dysplasia
D. Traumatic fibroma
Correct Answer: C
Rationale: Dysplastic leukoplakia is considered a potentially malignant disorder requiring
close evaluation.
