Integrated National Board Dental Examination (INBDE) — Questions and Answers

Question 1: Which pattern(s) of alveolar bone loss can occur in periodontitis?

Periodontitis does not cause bone loss
Horizontal bone loss only
Vertical bone loss only
Both horizontal and vertical bone loss (Correct answer)

Correct answer: Both horizontal and vertical bone loss

Periodontitis may produce horizontal bone loss (uniform reduction in bone height), vertical/angular defects, or both, depending on local anatomy and plaque distribution.

Question 2: Which cranial nerve is responsible for the general sensory innervation of the teeth and gums?

Hypoglossal nerve (CN XII)
Trigeminal nerve (CN V) (Correct answer)
Facial nerve (CN VII)
Glossopharyngeal nerve (CN IX)

Correct answer: Trigeminal nerve (CN V)

The trigeminal nerve (CN V) provides the primary sensory innervation to the teeth, periodontal ligament, and gingiva via its maxillary and mandibular divisions.

Question 3: The occlusal scheme most commonly recommended for complete dentures is:

Edge-to-edge bite
Canine-guided occlusion
Lingualized occlusion or bilateral balanced occlusion (Correct answer)
Group function occlusion

Correct answer: Lingualized occlusion or bilateral balanced occlusion

Bilateral balanced occlusion (contacts on both sides in all excursive movements) or lingualized occlusion is recommended for complete dentures to stabilize the denture base and prevent tipping.

Question 4: A lady, 53, has been identified as having "burning mouth syndrome." In this condition, what area of the mouth is most usually affected?

Hard palate
Tongue (Correct answer)
Soft palate
Lips

Correct answer: Tongue

Burning Mouth Syndrome (BMS) is a chronic pain condition characterized by a burning sensation in the mouth without any identifiable oral lesions or systemic disease. The tongue, particularly the anterior two-thirds and the tip, is the most commonly affected site. Patients often describe the sensation as scalding or tingling, sometimes accompanied by altered taste or dry mouth.

Question 5: The Angle classification of malocclusion is based on the relationship between which teeth?

Upper and lower central incisors
Maxillary and mandibular first permanent molars (and maxillary canine to lower first premolar) (Correct answer)
Maxillary and mandibular canines only
Upper and lower second premolars

Correct answer: Maxillary and mandibular first permanent molars (and maxillary canine to lower first premolar)

Angle's classification uses the mesiobuccal cusp of the upper first molar relative to the buccal groove of the lower first molar (and canine to premolar) as reference points.

Question 6: The leeway space (E-space) refers to the size difference between which groups of teeth?

Space between the permanent first molar and permanent canine
Primary incisors and permanent incisors
Arch length increase due to second molar eruption
Combined width of primary canine and molars minus combined width of permanent canine and premolars (Correct answer)

Correct answer: Combined width of primary canine and molars minus combined width of permanent canine and premolars

Leeway space is the difference between the combined mesiodistal width of the primary C, D, E (canine and two molars) and their permanent successors (C, PM1, PM2) — approximately 1.5 mm per side in the mandible.

Question 7: A patient presents with multiple amalgam restorations and complains of a metallic taste and burning sensation. The adjacent mucosa shows a white, striated lesion that cannot be wiped off. This is most likely:

Chemical burn
Candidiasis
Oral lichenoid reaction (Correct answer)
Leukoplakia

Correct answer: Oral lichenoid reaction

Oral lichenoid reactions in contact with amalgam restorations present as white striated lesions that do not rub off, similar to lichen planus.

Question 8: Which of the following is the MOST important factor in determining the long-term success of an implant?

Use of platform switching
Crown-to-implant ratio
Brand of implant system used
Adequate bone quality and quantity at the implant site (Correct answer)

Correct answer: Adequate bone quality and quantity at the implant site

Adequate bone quality and quantity at the implant site is the most critical factor for osseointegration and long-term implant success.

Question 9: Fibrous dysplasia of the jaw characteristically demonstrates which radiographic appearance?

Well-defined radiolucency with sclerotic border
Dense radiopaque mass with sun-ray pattern
Ground-glass opacity with poorly defined borders blending into normal bone (Correct answer)
Multiple radiolucent areas separated by dense septa ('soap bubble')

Correct answer: Ground-glass opacity with poorly defined borders blending into normal bone

Fibrous dysplasia shows a classic 'ground-glass' or 'orange peel' radiodensity with ill-defined borders that blend imperceptibly into surrounding normal bone.

Question 10: Fluoride varnish application in pediatric patients is recommended beginning at:

Age 3 years when all primary teeth are erupted
Birth (at the first well-child visit)
Age 2 years
Eruption of the first primary tooth (approximately 6 months) (Correct answer)

Correct answer: Eruption of the first primary tooth (approximately 6 months)

The American Academy of Pediatric Dentistry (AAPD) recommends fluoride varnish application beginning at the eruption of the first primary tooth, approximately 6 months of age.

Question 11: In a healthy periodontium, the apical termination of the junctional epithelium coincides with the:

Mid-root cementum
Free gingival margin
Cemento-enamel junction (CEJ) (Correct answer)
Alveolar crest

Correct answer: Cemento-enamel junction (CEJ)

Under healthy conditions, the apical end of the junctional epithelium is located at the CEJ, with no apical migration onto the root surface.

Question 12: A 35-year-old patient has a 5 mm probing depth at a mandibular molar with bleeding on probing and 3 mm of clinical attachment loss. How would you classify this finding?

Stage III periodontitis
Stage I periodontitis
Stage II periodontitis (Correct answer)
Gingivitis

Correct answer: Stage II periodontitis

Stage II periodontitis is characterized by clinical attachment loss of 3–4 mm and probing depths of 5–6 mm.

Question 13: A patient returns 1 week after extraction with dry socket. Which clinical feature most confirms this diagnosis?

Swelling and trismus
Purulent discharge from the socket
Absence of blood clot with exposed bone and intense pain (Correct answer)
Fever and lymphadenopathy

Correct answer: Absence of blood clot with exposed bone and intense pain

Alveolar osteitis (dry socket) is characterized by loss of the clot, exposed alveolar bone, and severe, radiating pain typically 2–4 days post-extraction.

Question 14: Pulp therapy for a carious primary molar with a normal radiograph and no spontaneous pain, but mechanical pulp exposure, is best treated by:

Pulpotomy with mineral trioxide aggregate (MTA) or ferric sulfate (Correct answer)
Immediate extraction
Indirect pulp cap
Direct pulp cap with calcium hydroxide

Correct answer: Pulpotomy with mineral trioxide aggregate (MTA) or ferric sulfate

A pulpotomy removes the coronal pulp, which is inflamed from caries proximity, while preserving vital radicular pulp tissue; MTA or ferric sulfate are current evidence-based agents for primary tooth pulpotomy.

Question 15: The principal fibers of the periodontal ligament that run from the alveolar crest obliquely to insert into the root are called:

Apical fibers
Alveolar crest fibers
Horizontal fibers
Oblique fibers (Correct answer)

Correct answer: Oblique fibers

Oblique fibers are the most numerous PDL principal fibers, running obliquely from alveolar bone to cementum to resist masticatory forces.

Question 16: A patient develops trismus after an inferior alveolar nerve block. The most likely cause is:

Hematoma formation in the medial pterygoid muscle (Correct answer)
Allergic reaction to the anesthetic
Injection into the parotid gland
Needle tip contacting the mandibular condyle

Correct answer: Hematoma formation in the medial pterygoid muscle

Trismus after an IAN block most commonly results from hematoma or direct trauma to the medial pterygoid muscle from the needle.

Question 17: Pemphigus vulgaris involves oral mucosa due to autoantibodies directed against:

BP180 (type XVII collagen) at the hemidesmosome
Desmoglein-3 (desmosomal adhesion protein) (Correct answer)
Fibronectin in the connective tissue
Laminin-332 at the basement membrane

Correct answer: Desmoglein-3 (desmosomal adhesion protein)

Pemphigus vulgaris results from IgG autoantibodies against desmoglein-3 (and sometimes desmoglein-1), disrupting intercellular adhesion and causing intraepithelial blistering.

Question 18: Tetracyclines are contraindicated in children under 8 years old primarily because they:

Inhibit cartilage growth at the epiphyseal plates
Cause nephrotoxicity in developing kidneys
Increase risk of intracranial hypertension in pediatric patients
Bind to calcium in developing teeth and bone, causing permanent discoloration and enamel hypoplasia (Correct answer)

Correct answer: Bind to calcium in developing teeth and bone, causing permanent discoloration and enamel hypoplasia

Tetracyclines chelate calcium and incorporate into mineralizing structures, causing intrinsic yellow-brown tooth staining and enamel hypoplasia in children under 8 during crown development.

Question 19: What is considered the primary etiologic factor initiating periodontal disease?

Dental calculus (tartar)
Malocclusion
Bacterial dental plaque biofilm (Correct answer)
Occlusal trauma

Correct answer: Bacterial dental plaque biofilm

Bacterial plaque biofilm is the essential primary cause of periodontal disease; it initiates the host inflammatory response that ultimately destroys periodontal tissues.

Question 20: Which cell type in dental pulp is responsible for synthesizing collagen type III (reticulin fibers)?

Odontoblasts
Dendritic cells
Fibroblasts (Correct answer)
Macrophages

Correct answer: Fibroblasts

Pulpal fibroblasts synthesize the collagen type III reticulin fibers that form the loose connective tissue framework of the dental pulp.

Question 21: Which radiographic technique is best suited for detecting interproximal caries in posterior teeth?

Periapical radiograph
Occlusal radiograph
Bitewing radiograph (Correct answer)
Panoramic radiograph

Correct answer: Bitewing radiograph

Bitewing radiographs provide the ideal projection for detecting early interproximal caries in posterior teeth because they capture both crowns and crestal bone without superimposition.

Question 22: In dental implant terminology, osseointegration is defined as:

The growth of bone into the macro-roughened surface of the implant fixture
Integration of the abutment with the soft tissue cuff
Fibrous encapsulation of the implant by dense connective tissue
Direct structural and functional contact between living bone and the implant surface at the light microscopic level (Correct answer)

Correct answer: Direct structural and functional contact between living bone and the implant surface at the light microscopic level

Osseointegration (Brånemark's definition) is a direct bone-to-implant contact at the light microscopic level without any intervening fibrous tissue layer.

Question 23: Methemoglobinemia is a specific adverse effect associated with which local anesthetic?

Prilocaine (Correct answer)
Articaine
Bupivacaine
Lidocaine

Correct answer: Prilocaine

Prilocaine metabolism produces ortho-toluidine, which oxidizes hemoglobin iron to the ferric state, causing methemoglobinemia at high doses.

Question 24: Ameloblastoma is most commonly located in which area of the jaw?

Posterior mandible (molar-ramus region) (Correct answer)
Anterior maxilla
Anterior mandible
Posterior maxilla

Correct answer: Posterior mandible (molar-ramus region)

Approximately 80% of ameloblastomas occur in the mandible, with the majority in the posterior molar-ramus region.

Question 25: Which layer of enamel is formed first during tooth development?

Striae of Retzius
Outer enamel layer
Inner enamel layer (Correct answer)
Dentinoenamel junction layer

Correct answer: Inner enamel layer

The inner enamel layer adjacent to the dentinoenamel junction is formed first as ameloblasts begin secreting enamel from that interface outward.

Question 26: NSAIDs reduce dental pain primarily by inhibiting which enzyme?

Thromboxane synthetase specifically
Cyclooxygenase (COX), reducing prostaglandin E2 synthesis (Correct answer)
Phospholipase A2
Lipoxygenase (LOX)

Correct answer: Cyclooxygenase (COX), reducing prostaglandin E2 synthesis

NSAIDs inhibit cyclooxygenase-1 and -2 (COX-1/COX-2), blocking the conversion of arachidonic acid to prostaglandins, reducing peripheral sensitization and inflammation.

Question 27: Which index measures the severity of periodontal disease by assessing loss of attachment and bone level?

Periodontal Disease Index (PDI) (Correct answer)
OHI-S (Oral Hygiene Index Simplified)
Community Periodontal Index (CPI)
DMFT index

Correct answer: Periodontal Disease Index (PDI)

The Periodontal Disease Index (PDI) evaluates gingival inflammation plus sulcus depth and attachment level, reflecting both tissue and bone changes.

Question 28: Which condition is characterized by numerous odontogenic keratocysts, basal cell carcinomas of the skin, and skeletal anomalies?

Multiple endocrine neoplasia type 1
Gardner syndrome
Cowden syndrome
Gorlin syndrome (Nevoid basal cell carcinoma syndrome) (Correct answer)

Correct answer: Gorlin syndrome (Nevoid basal cell carcinoma syndrome)

Gorlin syndrome (NBCCS) is caused by PTCH1 mutations and classically presents with multiple OKCs, basal cell carcinomas, calcified falx cerebri, and bifid ribs.

Question 29: Which tooth movement type results in the highest rate of root resorption during orthodontic treatment?

Intrusion (Correct answer)
Tipping
Torque (root torque)
Bodily movement

Correct answer: Intrusion

Intrusion is associated with the highest risk of root resorption because it concentrates pressure at the root apex.

Question 30: Post-operative sensitivity after posterior composite resin placement is most commonly attributed to:

Allergic reaction to bis-GMA resin
Polymerization shrinkage creating gap formation at the cavity margins (Correct answer)
Excessive occlusal contacts on the new restoration
Fluoride release from the composite

Correct answer: Polymerization shrinkage creating gap formation at the cavity margins

Composite polymerization shrinkage (approximately 1.5–3%) can create microleakage gaps at the dentin interface, allowing fluid movement in dentinal tubules and causing post-op sensitivity.

Question 31: Which type of connector joins two or more retainers in a fixed partial denture?

Major connector
Rest seat
Rigid connector (Correct answer)
Pontic

Correct answer: Rigid connector

A rigid connector (solder joint or cast connector) joins retainers in a fixed partial denture, providing a solid, non-movable union between components.

Integrated National Board Dental Examination (INBDE)

The INBDE is a two-day computer-based licensure examination administered by the Joint Commission on National Dental Examinations (JCNDE) that assesses whether dental school graduates possess the knowledge and clinical competency required for entry-level dental practice in the United States.

Questions

35 min

Time Limit

75%

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