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

Question 1: Which type of ameloblastoma is most commonly found in the posterior mandible and is characterized by islands of odontogenic epithelium within a fibrous stroma?

Solid/multicystic ameloblastoma (Correct answer)
Unicystic ameloblastoma
Desmoplastic ameloblastoma
Peripheral ameloblastoma

Correct answer: Solid/multicystic ameloblastoma

The solid/multicystic (conventional) ameloblastoma is the most common type, arising predominantly in the posterior mandible with classic histological patterns including follicular and plexiform subtypes.

Question 2: A 5-year-old child presents with bilateral jaw swelling causing an upward gaze appearance. Radiographs show multilocular radiolucencies. What is the most likely diagnosis?

Fibrous dysplasia
Giant cell granuloma
Osteosarcoma
Cherubism (Correct answer)

Correct answer: Cherubism

Cherubism is an autosomal dominant condition causing bilateral fibrous replacement of jaw bone in childhood, producing multilocular radiolucencies and the characteristic upward gaze due to orbital floor involvement.

Question 3: The closest speaking space refers to:

The closest vertical relationship of upper and lower teeth during speech (Correct answer)
The distance between the lips at rest
Freeway space (interocclusal distance)
Occlusal vertical dimension

Correct answer: The closest vertical relationship of upper and lower teeth during speech

The closest speaking space (1–2 mm) is the minimum distance between maxillary and mandibular teeth observed during phonation of sibilant sounds like 's'.

Question 4: Pier abutments in fixed prosthodontics are a problem because they:

Are unable to support porcelain veneers
Have insufficient root surface area
Create a Class I lever when the terminal abutments flex differentially (Correct answer)
Increase the span length of the bridge excessively

Correct answer: Create a Class I lever when the terminal abutments flex differentially

A pier (middle) abutment creates a Class I lever arm; when one terminal abutment is depressed, the pier acts as a fulcrum, placing destructive tipping forces on the other terminal abutment.

Question 5: Which bacteria is most commonly found in failed root canal treatments?

Porphyromonas gingivalis
Fusobacterium nucleatum
Streptococcus mutans
Enterococcus faecalis (Correct answer)

Correct answer: Enterococcus faecalis

Enterococcus faecalis is the most frequently isolated organism in failed root canals due to its ability to survive in the alkaline environment created by calcium hydroxide.

Question 6: Periodontal probing depth is measured from the:

Cemento-enamel junction to the alveolar crest
Gingival margin to the base of the pocket (Correct answer)
Mucogingival junction to the gingival margin
Alveolar crest to the base of the pocket

Correct answer: Gingival margin to the base of the pocket

Probing depth is the distance from the free gingival margin to the base of the periodontal pocket or sulcus.

Question 7: Dental porcelain is classified as a ceramic primarily because it contains:

Inorganic non-metallic crystalline or glass materials (Correct answer)
Organic polymer matrix
Metal oxides only
Zinc phosphate cement

Correct answer: Inorganic non-metallic crystalline or glass materials

Ceramics are inorganic, non-metallic materials; dental porcelain is primarily composed of silica, feldspar, and alumina in a glass matrix.

Question 8: What is the primary purpose of EDTA in root canal treatment?

Dissolution of organic tissue
Removal of the smear layer (chelation of inorganic components) (Correct answer)
Lubrication of instruments
Antimicrobial activity

Correct answer: Removal of the smear layer (chelation of inorganic components)

EDTA (ethylenediaminetetraacetic acid) chelates calcium ions in the smear layer and dentinal walls, removing the inorganic component to open dentinal tubules.

Question 9: Aggressive periodontitis in young patients is most commonly associated with which organism?

Treponema denticola
Aggregatibacter actinomycetemcomitans (Correct answer)
Prevotella intermedia
Tannerella forsythia

Correct answer: Aggregatibacter actinomycetemcomitans

Aggregatibacter actinomycetemcomitans (Aa) is strongly associated with localized aggressive periodontitis, particularly in adolescents and young adults.

Question 10: The vertical dimension of rest (VDR) is typically how much greater than the vertical dimension of occlusion (VDO)?

0–1 mm
5–7 mm
2–4 mm (Correct answer)
8–10 mm

Correct answer: 2–4 mm

The interocclusal distance (freeway space) between VDR and VDO is typically 2–4 mm, representing the resting position of the mandible where the elevator muscles are in tonic equilibrium.

Question 11: In which of the following transport processes do solid materials enter the cell in membrane-bound vesicles?

Passive transport
Osmosis
Phagocytosis (Correct answer)
Pinocytosis

Correct answer: Phagocytosis

In active transport, materials enter the cell in membrane-bound vesicles that are formed by the membrane. This process is generally known as endocytosis and is of two types. Endocytosis of solid material and liquid materials is called phagocytosis and pinocytosis respectively.

Question 12: The working time of zinc phosphate cement can be extended by:

Mixing rapidly in a circular motion
Spatulating on a cold, thick glass slab (Correct answer)
Increasing the powder-to-liquid ratio
Adding more liquid to the mix

Correct answer: Spatulating on a cold, thick glass slab

Cooling the glass slab to 18°C slows the exothermic setting reaction, extending working time; large slab area also dissipates heat.

Question 13: Which radiographic finding is most consistent with a diagnosis of condensing osteitis?

Periapical radiopacity with diffuse borders (Correct answer)
Periapical radiolucency with diffuse borders
Widened periodontal ligament space
Loss of lamina dura

Correct answer: Periapical radiopacity with diffuse borders

Condensing osteitis appears as a periapical radiopacity representing localized bone sclerosis in response to a low-grade inflammatory stimulus from the pulp.

Question 14: Naloxone is the reversal agent for which class of drugs?

Anticholinergics
Benzodiazepines
Barbiturates
Opioids (Correct answer)

Correct answer: Opioids

Naloxone is a competitive opioid receptor antagonist that rapidly reverses respiratory depression, sedation, and analgesia caused by opioid overdose.

Question 15: The apical constriction (minor diameter) of the canal is located approximately:

0.5–1.0 mm coronal to the anatomic apex (Correct answer)
At the mid-root level
At the radiographic apex
At the cemento-dentinal junction

Correct answer: 0.5–1.0 mm coronal to the anatomic apex

The apical constriction, where the canal is narrowest, is located approximately 0.5–1.0 mm coronal to the anatomic apex and is the ideal endpoint for canal instrumentation.

Question 16: Which of the following is a contraindication to implant placement?

Age over 60
History of radiation to the head and neck (Correct answer)
Single tooth replacement in posterior region
Controlled type 2 diabetes (HbA1c <7%)

Correct answer: History of radiation to the head and neck

Prior radiation therapy to the head and neck significantly compromises bone vascularity and healing, increasing the risk of osteoradionecrosis and implant failure.

Question 17: Which drug interaction is most concerning when prescribing metronidazole?

Warfarin — increased anticoagulant effect (Correct answer)
Ibuprofen — nephrotoxicity
Amoxicillin — reduced efficacy
Lidocaine — cardiac arrhythmia

Correct answer: Warfarin — increased anticoagulant effect

Metronidazole inhibits CYP2C9, reducing warfarin metabolism and significantly increasing INR, raising the risk of bleeding.

Question 18: Which type of porcelain failure most commonly occurs in porcelain-fused-to-metal restorations?

Cohesive failure within the porcelain (Correct answer)
Compressive failure at the occlusal surface
Crazing of surface glaze
Adhesive failure at the metal-porcelain interface

Correct answer: Cohesive failure within the porcelain

Cohesive failure (fracture within the porcelain itself) is the most common type of failure in PFM restorations, often related to inadequate support or occlusal overload.

Question 19: Which furcation classification indicates that the furcation can be completely probed through from one side to the other?

Class III (Correct answer)
Class II
Class I
Class IV

Correct answer: Class III

Class III (through-and-through) furcation involvement means the probe passes completely through the furcation from the buccal to lingual/palatal surface.

Question 20: Obturation of a root canal is considered acceptable when:

Fill material ends 0–2 mm short of the radiographic apex with no voids (Correct answer)
The canal is completely filled with sealer alone
Gutta-percha reaches the radiographic apex
Fill material extends 1 mm beyond the apex

Correct answer: Fill material ends 0–2 mm short of the radiographic apex with no voids

Ideal obturation terminates 0–2 mm short of the radiographic apex (at the apical constriction) with well-adapted gutta-percha and minimal sealer without voids.

Question 21: Residual ridge resorption after tooth extraction follows a pattern that is:

Ceases after 6 months post-extraction
Greater in the maxilla vertically, greater in the mandible horizontally
Greater in the mandible in all dimensions (Correct answer)
Equal in maxilla and mandible

Correct answer: Greater in the mandible in all dimensions

The mandibular ridge typically resorbs 4 times faster than the maxilla overall, and resorption is greater in all dimensions in the mandible, making mandibular dentures more challenging.

Question 22: The best disinfection method for a digital radiographic sensor covered with a disposable hygienic barrier is to

spray and wipe with 45% isopropyl alcohol.
spray and wipe with 69% isopropyl alcohol.
spray and wipe with 70% isopropyl alcohol. (Correct answer)
spray and wipe with 71% isopropyl alcohol.

Correct answer: spray and wipe with 70% isopropyl alcohol.

By increasing the rate of production, the clinic can see more patients, perform more procedures, and generate higher revenue, leading to improved business performance. This can be achieved through optimizing operational efficiency, improving scheduling, and enhancing staff productivity

Question 23: What is the working length in endodontics?

The length of gutta-percha used for obturation
The distance from a reference point to the apical constriction where instrumentation ends (Correct answer)
The full length of the root canal from orifice to apex
The length of the root as measured on the radiograph

Correct answer: The distance from a reference point to the apical constriction where instrumentation ends

Working length is the measured distance from an occlusal/incisal reference point to the apical stop (apical constriction), establishing the limit of instrumentation.

Question 24: A 45-year-old patient presents with a white patch on the lateral border of the tongue that cannot be wiped off. Biopsy reveals epithelial dysplasia. What is the most appropriate diagnosis?

Leukoplakia (Correct answer)
Lichen planus
Candidiasis
Leukoedema

Correct answer: Leukoplakia

Leukoplakia is a clinical term for a white patch that cannot be wiped off and has no other identifiable cause; dysplasia on biopsy confirms its premalignant potential.

Question 25: Flumazenil is used as an antagonist for which drug class?

Antihistamines
Benzodiazepines (Correct answer)
Barbiturates
Opioids

Correct answer: Benzodiazepines

Flumazenil is a competitive benzodiazepine receptor antagonist used to reverse the sedative effects of benzodiazepines in overdose or post-procedure.

Question 26: Amalgam's strength is primarily derived from which phase?

Gamma-1 phase (silver-mercury) (Correct answer)
Gamma-2 phase (tin-mercury)
Delta phase (copper-tin)
Gamma phase (unreacted silver-tin)

Correct answer: Gamma-1 phase (silver-mercury)

The gamma-1 phase (Ag2Hg3) is the matrix phase that gives amalgam its strength, while gamma-2 (Sn7-8Hg) is the weakest and most corrosion-prone phase.

Question 27: The neutral zone in complete denture construction represents:

The area of maximum bone support
The space between the residual ridges
The area where buccal and lingual muscle forces are in equilibrium (Correct answer)
The occlusal plane height

Correct answer: The area where buccal and lingual muscle forces are in equilibrium

The neutral zone is the area in the edentulous mouth where the outward tongue pressure equals the inward cheek and lip pressure, providing the ideal location for artificial teeth.

Question 28: The 'sunburst' or 'sunray' pattern on radiographs of the jaw in a teenager is most characteristic of which malignancy?

Metastatic carcinoma
Osteosarcoma (Correct answer)
Ewing's sarcoma
Multiple myeloma

Correct answer: Osteosarcoma

Osteosarcoma classically produces a 'sunburst' or 'sunray' radiographic pattern due to periosteal reaction perpendicular to the cortex, often seen in adolescents and young adults.

Question 29: Class II composite restorations are most challenging compared to Class I because of the need for:

Extended curing times
Use of a rubber dam
Greater occlusal reduction
Restoration of the proximal contact and marginal ridge (Correct answer)

Correct answer: Restoration of the proximal contact and marginal ridge

Restoring a proximal contact, marginal ridge, and gingival margin against an adjacent tooth in a confined space makes Class II composites technically demanding.

Question 30: Galvanism in the oral cavity occurs when:

Gold alloy undergoes tarnish
Two dissimilar metals in saliva create an electrical current (Correct answer)
Composite polymerization creates heat
Amalgam corrodes in an acid environment

Correct answer: Two dissimilar metals in saliva create an electrical current

Oral galvanism results from the electrochemical coupling of two dissimilar metals (e.g., amalgam and gold) in the electrolyte of saliva, generating a measurable galvanic current.

Question 31: Which of the following layers of the heart is primarily composed of cardiac muscle?

Endocardium
Pericardium
Myocardium (Correct answer)
Epicardium

Correct answer: Myocardium

Mycocardium or middle layer of the heart consists of cardiac muscle. The heart is a highly specialized pumping organ composed of the following layers Endocardium (lining coat; epithelium) Myocardium (middle coat; cardiac muscle), and Epicardium (external coat or visceral layer of pericardium; epithelium).

Question 32: Which of the following peptide hormones is released in response to the stimulation of pituitary gonadotropes?

ACTH
growth hormone
follicle-stimulating hormone (Correct answer)
prolactin

Correct answer: follicle-stimulating hormone

The pituitary gonadotrophs are cells that secrete the gonadotrophic peptide hormones, follicle-stimulating hormone (FSH), and leutinizing hormone (LH).

Question 33: Clinical attachment level (CAL) is calculated as:

Probing depth minus recession from CEJ to gingival margin
Distance from CEJ to alveolar crest
Probing depth plus recession (distance from CEJ to gingival margin) (Correct answer)
Probing depth alone

Correct answer: Probing depth plus recession (distance from CEJ to gingival margin)

CAL = probing depth + recession (when the gingival margin is apical to the CEJ), giving a true measure of attachment loss from the CEJ.

Question 34: What is the particulate filtration rate of a level 1 mask at the standard of 0.1 microns?

85-89%
95-97% (Correct answer)
98-99%
90-94%

Correct answer: 95-97%

The particulate filtration rate of a level 1 mask at the standard of 0.1 microns

Question 35: A patient taking warfarin requires a dental extraction. The INR is 2.5. The most appropriate management is to:

Proceed with extraction using local hemostatic measures (Correct answer)
Stop warfarin 3 days before extraction
Postpone treatment indefinitely
Refer to physician to switch to heparin

Correct answer: Proceed with extraction using local hemostatic measures

For patients on warfarin with an INR ≤3.5, routine dental extractions can proceed safely with local hemostatic measures such as pressure and sutures.

Question 36: Which condition is characterized by intense burning of the oral mucosa with no identifiable clinical or laboratory abnormality and predominantly affects postmenopausal women?

Erythema migrans
Burning mouth syndrome (Correct answer)
Atrophic glossitis
Contact mucositis

Correct answer: Burning mouth syndrome

Burning mouth syndrome (BMS) is a chronic orofacial pain disorder with burning sensations but no identifiable mucosal lesions; it predominantly affects postmenopausal women and has multifactorial etiology.

Question 37: Necrotizing sialometaplasia most commonly occurs on the hard palate and can mimic squamous cell carcinoma clinically and histologically. What is its most likely etiology?

Ischemic infarction of salivary gland tissue (Correct answer)
Trauma-induced salivary gland neoplasm
Viral infection of salivary glands
Autoimmune destruction of acini

Correct answer: Ischemic infarction of salivary gland tissue

Necrotizing sialometaplasia results from ischemic necrosis of minor salivary gland lobules, typically following trauma, surgery, or vascular compromise, with subsequent squamous metaplasia of ducts.

Question 38: Which of the following is not considered to be common risk factor for CVA / stroke?

Hypertension
Atherosclerosis
Orthostatic hypotension (Correct answer)
Diabetes

Correct answer: Orthostatic hypotension

Orthostatic hypertension is not a common risk factor for CVA/stroke. The common risk factors for CVA / stroke include diabetes, atherosclerosis, hypertension, and heart disease.

Question 39: The zona pellucida of the enamel organ is also known as:

Stellate reticulum (Correct answer)
Cervical loop
Stratum intermedium
Outer enamel epithelium

Correct answer: Stellate reticulum

The stellate reticulum is the star-shaped cell layer of the enamel organ that provides a cushioning effect and nutrition to the inner enamel epithelium.

Question 40: Which liner material provides therapeutic benefit by stimulating reparative dentin formation?

Zinc phosphate cement
Glass ionomer cement
Calcium hydroxide (Ca(OH)2) (Correct answer)
Zinc oxide eugenol

Correct answer: Calcium hydroxide (Ca(OH)2)

Calcium hydroxide (Ca(OH)2) has a high pH that is bactericidal and stimulates odontoblast differentiation to produce reparative (tertiary) dentin when placed near the pulp.

Question 41: A semi-adjustable articulator can replicate:

All mandibular movements with perfect accuracy
Only centric occlusion
Average condylar settings with some adjustability for protrusive and lateral movements (Correct answer)
Exact patient-specific condylar paths using custom incisal guidance

Correct answer: Average condylar settings with some adjustability for protrusive and lateral movements

Semi-adjustable articulators accept protrusive records and facebow transfers to approximate condylar guidance, balancing side angles, and incisal guidance for most clinical procedures.

Question 42: Which finish line design provides the best marginal seal and esthetics for an all-ceramic crown?

Beveled shoulder
Knife-edge margin
Featheredge
Deep chamfer or shoulder with rounded internal line angle (Correct answer)

Correct answer: Deep chamfer or shoulder with rounded internal line angle

A deep chamfer or shoulder (0.8–1.5 mm) with a rounded internal line angle provides adequate ceramic bulk for strength and good marginal fit for all-ceramic restorations.

Question 43: Which antibiotic is the first-line prophylaxis for patients at high risk of infective endocarditis undergoing dental procedures?

Metronidazole
Amoxicillin (Correct answer)
Clindamycin
Doxycycline

Correct answer: Amoxicillin

Amoxicillin 2 g orally one hour before the procedure is the AHA-recommended first-line prophylaxis for high-risk cardiac patients undergoing dental procedures.

Question 44: Which crown-to-root ratio is generally considered the minimum acceptable for a tooth to serve as an abutment?

1:1.5
1:2
1:1 (Correct answer)
2:3

Correct answer: 1:1

A crown-to-root ratio of 1:1 is generally considered the minimum acceptable for a tooth to be used as a fixed prosthetic abutment, with 2:3 being ideal.

Question 45: A patient with HIV presents with painless, bluish-purple nodules on the hard palate. What is the most likely diagnosis?

Bacillary angiomatosis
Kaposi's sarcoma (Correct answer)
Necrotizing ulcerative periodontitis
Hairy leukoplakia

Correct answer: Kaposi's sarcoma

Kaposi's sarcoma is an AIDS-defining malignancy commonly presenting as blue-purple vascular lesions on the palate in HIV-infected individuals.

Question 46: Which of the following is the most effective way to grow a dental clinic?

Self-insurance
Create a business plan (Correct answer)
Accept more insurance plans
Decrease the copayments

Correct answer: Create a business plan

A comprehensive business plan will help outline strategies for growth, identify target markets, set financial goals, and create a roadmap for achieving them. It encompasses all aspects of the business, including marketing, operations, and financial planning, providing a structured approach to growth.

Question 47: Gutta-percha is primarily composed of which material?

Resin and glass ionomer
Trans-polyisoprene (rubber), zinc oxide, and barium sulfate (Correct answer)
Zinc oxide and eugenol
Calcium hydroxide and silicone

Correct answer: Trans-polyisoprene (rubber), zinc oxide, and barium sulfate

Gutta-percha points consist primarily of trans-polyisoprene (gutta-percha resin), zinc oxide (filler), barium sulfate (radiopacifier), and waxes/resins.

Question 48: The Knoop hardness test is most appropriate for measuring which dental material?

Alginate
Impression materials
Dental ceramics and enamel (Correct answer)
Elastomeric impression materials

Correct answer: Dental ceramics and enamel

The Knoop hardness test uses a rhombus-shaped diamond indenter and is ideal for hard, brittle materials like dental ceramics and enamel.

Question 49: Which systemic condition is most strongly associated with an increased risk of periodontitis?

Hypothyroidism
Type 2 diabetes mellitus (Correct answer)
Osteoporosis
Hyperlipidemia

Correct answer: Type 2 diabetes mellitus

Type 2 diabetes mellitus significantly increases the risk and severity of periodontitis through impaired neutrophil function, advanced glycation end-products, and altered wound healing.

Question 50: Protrusive records in complete denture fabrication are used to set the:

Condylar guidance angle on the articulator (Correct answer)
Centric relation position
Horizontal overlap of anterior teeth
Occlusal vertical dimension

Correct answer: Condylar guidance angle on the articulator

Protrusive records allow the clinician to program the condylar guidance angle (Hanau's formula: H = P/8 + 12) on the semi-adjustable articulator.

Question 51: Which type of bone defect has the best prognosis for regeneration?

Crater defect
Two-wall defect
Three-wall (intrabony) defect (Correct answer)
One-wall (hemiseptal) defect

Correct answer: Three-wall (intrabony) defect

Three-wall intrabony defects have the best regenerative prognosis because three bony walls provide maximum blood supply, stability, and a scaffold for regeneration.

Question 52: Vertical root fracture is most commonly associated with:

Excessive irrigation pressure
Perforation with a post drill
Excessive lateral condensation during obturation (Correct answer)
Trauma from occlusion

Correct answer: Excessive lateral condensation during obturation

Excessive lateral condensation pressure during cold lateral compaction of gutta-percha is a major cause of vertical root fracture.

Question 53: The retention of a full-crown preparation is most influenced by:

Occlusal reduction amount
Taper of the axial walls (convergence angle) (Correct answer)
Surface roughness of the preparation
Margin design (chamfer vs feather edge)

Correct answer: Taper of the axial walls (convergence angle)

Axial wall taper (convergence angle) is the most critical retention factor; ideally 6–10° total occlusal convergence maximizes both retention and withdrawal path.

Question 54: The epithelial rests of Malassez are remnants of which structure?

Hertwig's epithelial root sheath (Correct answer)
Reduced enamel epithelium
Dental lamina
Nasmyth's membrane

Correct answer: Hertwig's epithelial root sheath

The epithelial rests of Malassez are remnants of Hertwig's epithelial root sheath that persist in the periodontal ligament throughout life.

Question 55: A free gingival graft is used primarily to:

Regenerate lost bone
Cover exposed root surfaces aesthetically
Increase the zone of attached (keratinized) gingiva (Correct answer)
Eliminate periodontal pockets

Correct answer: Increase the zone of attached (keratinized) gingiva

A free gingival graft harvested from the palate is the gold standard for augmenting the width of attached keratinized gingiva.

Question 56: Osseointegration of a dental implant refers to:

Direct structural and functional connection between bone and the implant surface (Correct answer)
Fibrous connective tissue encapsulation of the implant
The process of implant insertion surgery
Soft tissue healing around the abutment

Correct answer: Direct structural and functional connection between bone and the implant surface

Osseointegration is the direct bone-to-implant contact without an intervening fibrous layer, providing the rigid anchorage that dental implants depend upon.

Question 57: Amelogenesis imperfecta primarily affects which aspect of tooth development?

Dentin matrix formation
Pulp calcification
Enamel matrix formation and/or mineralization (Correct answer)
Root formation

Correct answer: Enamel matrix formation and/or mineralization

Amelogenesis imperfecta is a hereditary condition affecting the quantity and/or quality of enamel due to defects in enamel matrix proteins or their regulation.

Question 58: Hunter-Schreger bands in enamel are best described as:

Alternating zones of enamel rods cut in different planes (Correct answer)
Hypomineralized areas near the DEJ
Incremental lines of enamel formation
Cracks caused by acid etching

Correct answer: Alternating zones of enamel rods cut in different planes

Hunter-Schreger bands are optical phenomena produced by the alternating direction of enamel rods when viewed in reflected light.

Question 59: Which composite placement technique best minimizes polymerization shrinkage stress?

Oblique incremental placement (Correct answer)
Diagonal incremental placement
Bulk fill technique
Horizontal incremental placement

Correct answer: Oblique incremental placement

Oblique (diagonal) incremental placement reduces the C-factor (ratio of bonded to unbonded surfaces) and allows shrinkage stress relief as each increment cures.

Question 60: Sodium hypochlorite (NaOCl) is used as an irrigant in root canal therapy primarily because it:

Dissolves organic tissue and has broad antimicrobial activity (Correct answer)
Prevents instrument fracture
Chelates smear layer
Stimulates periapical healing

Correct answer: Dissolves organic tissue and has broad antimicrobial activity

Sodium hypochlorite is the primary root canal irrigant due to its ability to dissolve pulp tissue and its potent antimicrobial activity against endodontic pathogens.

Question 61: A newly hired dental assistant notices that several of the staff are not following proper infection control protocols. Where should this observation be reported?

FDA
OSHA (Correct answer)
EPA
COBRA

Correct answer: OSHA

OSHA is responsible for ensuring safe and healthy working conditions, which includes enforcing proper infection control protocols in dental offices to protect staff and patients.

Question 62: A patient presents with multiple basal cell carcinomas, calcified falx cerebri, and odontogenic keratocysts of the jaw. What syndrome is present?

Gorlin-Goltz syndrome (Correct answer)
Gardner syndrome
Cowden syndrome
Peutz-Jeghers syndrome

Correct answer: Gorlin-Goltz syndrome

Gorlin-Goltz (nevoid basal cell carcinoma) syndrome is characterized by multiple OKCs of the jaws, basal cell nevi/carcinomas, and calcification of the falx cerebri.

Question 63: The step-back technique in canal preparation refers to:

Using rotary instruments from coronal to apical
Alternating between two files of the same size
Beginning instrumentation at the apex and moving coronally
Progressively using larger files at shorter lengths to create a tapered canal (Correct answer)

Correct answer: Progressively using larger files at shorter lengths to create a tapered canal

In the step-back technique, after establishing the working length with the master apical file, larger files are used at progressively shorter lengths to create a funnel-shaped taper.

Question 64: Tetracyclines are contraindicated in children under 8 years of age because they:

Cause hepatic failure
Cause nephrotoxicity
Cause permanent tooth discoloration and enamel hypoplasia (Correct answer)
Inhibit bone growth

Correct answer: Cause permanent tooth discoloration and enamel hypoplasia

Tetracyclines chelate calcium and incorporate into developing teeth and bone, causing permanent yellow-gray discoloration and enamel hypoplasia in children under 8.

Question 65: Which cells produce the principal fibers of the periodontal ligament?

Undifferentiated mesenchymal cells
Fibroblasts (Correct answer)
Cementoblasts
Osteoblasts

Correct answer: Fibroblasts

Fibroblasts are the most numerous cells of the periodontal ligament and are responsible for synthesizing and maintaining the collagen fibers.

Question 66: Which of the following drugs is NOT a calcium channel blocker?

Metoprolol (Correct answer)
Verapamil
Amplodipine
Nifedipine

Correct answer: Metoprolol

Metoprolol is not a calcium channel blocker; it is a beta channel antagonist.

Question 67: Internal root resorption appears radiographically as:

A symmetric oval or round radiolucency within the root canal space (Correct answer)
External notching of the root surface
A radiolucency with irregular borders around the root
Blunting of the root apex

Correct answer: A symmetric oval or round radiolucency within the root canal space

Internal resorption appears as a smooth, round-to-oval radiolucent enlargement within the root canal, caused by clastic cells activated within the pulp.

Question 68: Which cell organelle is involved in concentration packaging and transportation of secretory material inside the cell?

Mitochondria
Endoplasmic reticulum
Ribosomes
Golgi complex (Correct answer)

Correct answer: Golgi complex

The Golgi complex is prominent in glandular cells and is thought to function in the production, concentration packaging, and transportation of secretory material.

Question 69: A maxillary first molar most commonly has how many canals?

4 (Correct answer)
2
5
3

Correct answer: 4

The maxillary first molar typically has 3 roots and most commonly 4 canals (2 in the mesiobuccal root — MB1 and MB2, 1 in the distobuccal, 1 in the palatal).

Question 70: Which impression material provides the highest dimensional accuracy and detail reproduction?

Alginate (irreversible hydrocolloid)
Polyvinyl siloxane (PVS/addition silicone) (Correct answer)
Zinc oxide eugenol paste
Polysulfide rubber

Correct answer: Polyvinyl siloxane (PVS/addition silicone)

Polyvinyl siloxane (addition silicone) provides the highest dimensional accuracy, excellent detail reproduction, and good dimensional stability over time.

Question 71: Which of the following is a true statement about the 'phoenix abscess'?

It is caused by periodontal pathogens
It is an acute exacerbation of a pre-existing chronic periapical lesion (Correct answer)
It always presents with a sinus tract
It occurs only in previously healthy teeth

Correct answer: It is an acute exacerbation of a pre-existing chronic periapical lesion

A phoenix abscess is an acute inflammatory exacerbation of a chronic periapical lesion, often occurring after endodontic instrumentation stirs up the existing pathology.

Question 72: An apicoectomy involves:

Intentional replantation of a tooth
Complete extraction of a tooth with periapical pathology
Internal bleaching of a discolored tooth
Surgical removal of the root apex and curettage of periapical tissue (Correct answer)

Correct answer: Surgical removal of the root apex and curettage of periapical tissue

An apicoectomy (root-end resection) involves surgical access, removal of the apical 3 mm of root, and curettage of periapical pathology, followed by root-end filling.

Question 73: What is the primary inorganic component of enamel?

Calcium carbonate
Hydroxyapatite (Correct answer)
Tricalcium phosphate
Calcium fluoride

Correct answer: Hydroxyapatite

Hydroxyapatite crystals [Ca10(PO4)6(OH)2] make up approximately 96% of the inorganic content of mature enamel.

Question 74: Which structure connects the enamel organ to the oral epithelium during tooth development?

Outer enamel epithelium
Dental lamina (Correct answer)
Stellate reticulum
Stratum intermedium

Correct answer: Dental lamina

The dental lamina is the band of epithelium that connects the developing enamel organ to the oral epithelium.

Question 75: The most common cause of complete denture instability in the mandible is:

Excessive vertical dimension
Incorrect tooth arrangement
Severe mandibular ridge resorption (Correct answer)
Improper shade selection of teeth

Correct answer: Severe mandibular ridge resorption

Severe mandibular ridge resorption reduces the supporting base area and alveolar height, making it difficult to achieve a stable, retentive mandibular denture.

Question 76: Cementum is thickest at which region of the root?

Apical third (Correct answer)
Furcation area
Cervical third
Middle third

Correct answer: Apical third

Cementum is thickest at the apex (apical third) of the root, where it can be 200–600 μm thick, compensating for passive eruption and wear.

Question 77: Which local anesthetic has the longest duration of action?

Lidocaine
Bupivacaine (Correct answer)
Prilocaine
Mepivacaine

Correct answer: Bupivacaine

Bupivacaine (Marcaine) has the longest duration of pulpal and soft tissue anesthesia among common dental local anesthetics due to its high protein-binding affinity.

Question 78: Which periodontal classification was adopted by the AAP/EFP World Workshop in 2017?

Stage and Grade classification (Correct answer)
Armitage 1999 classification
Page and Schroeder 1976 classification
AAP 1989 classification

Correct answer: Stage and Grade classification

The 2017 AAP/EFP World Workshop introduced the Stage (I–IV) and Grade (A–C) classification system to replace the previous aggressive/chronic periodontitis terminology.

Question 79: An employee is sick and asked to stay at home. What is the correct term for this control measure?

Administrative control
Work practice control
Hazard control
Engineering control (Correct answer)

Correct answer: Engineering control

Engineering controls involve physical modifications or changes to the work environment or equipment to reduce or eliminate workplace hazards. Examples include installing ventilation systems or using barriers to separate workers from hazards. Staying at home when sick does not fall under engineering control measures.

Question 80: Mineral trioxide aggregate (MTA) is used in endodontics for all of the following EXCEPT:

Pulp capping
Root-end filling
Perforation repair
Mechanical canal enlargement (Correct answer)

Correct answer: Mechanical canal enlargement

MTA is a biocompatible hydraulic cement used for pulp capping, root-end filling, and perforation repair, but it is not used for mechanical canal shaping.

Question 81: Which odontogenic cyst has the highest recurrence rate due to an aggressive, thin-walled epithelial lining that produces keratin?

Radicular cyst
Nasopalatine duct cyst
Odontogenic keratocyst (Correct answer)
Dentigerous cyst

Correct answer: Odontogenic keratocyst

The odontogenic keratocyst (OKC) has a high recurrence rate (25–60%) because its thin, friable parakeratinized epithelial lining is prone to incomplete removal and satellite cyst formation.

Question 82: Deflective occlusal contacts (prematurities) in centric relation that shift the mandible to maximum intercuspation are called:

Interferences
Fremitus
Centric relation-centric occlusion (CR-CO) discrepancies (Correct answer)
Working contacts

Correct answer: Centric relation-centric occlusion (CR-CO) discrepancies

CR-CO discrepancy occurs when premature contacts in centric relation force the mandible to shift anteriorly and laterally to reach maximum intercuspation (centric occlusion).

Question 83: Which type of oral cancer is most strongly associated with high-risk HPV infection, particularly HPV-16?

Floor of mouth squamous cell carcinoma
Buccal mucosa squamous cell carcinoma
Lower lip squamous cell carcinoma
Oropharyngeal squamous cell carcinoma (Correct answer)

Correct answer: Oropharyngeal squamous cell carcinoma

High-risk HPV-16 is strongly associated with oropharyngeal squamous cell carcinoma (tonsils, base of tongue), particularly in younger non-smokers, and carries a better prognosis than HPV-negative tumors.

Question 84: Which of the following is the most effective way to improve a dental clinic's business?

Decrease staff benefits
Increase rate of production (Correct answer)
Purchase life insurance
Decrease rate of amortization

Correct answer: Increase rate of production

Question 85: Nitrous oxide/oxygen sedation is contraindicated in which patient?

A patient with controlled hypertension
A patient with mild anxiety
A patient with chronic obstructive pulmonary disease (COPD) (Correct answer)
A 10-year-old child

Correct answer: A patient with chronic obstructive pulmonary disease (COPD)

Patients with COPD rely on hypoxic drive; supplemental oxygen via nitrous oxide sedation can suppress their respiratory drive and cause respiratory depression.

Question 86: The maximum recommended dose of lidocaine with epinephrine in a healthy adult is:

10 mg/kg (max 600 mg)
3.0 mg/kg (max 200 mg)
7.0 mg/kg (max 500 mg) (Correct answer)
4.4 mg/kg (max 300 mg)

Correct answer: 7.0 mg/kg (max 500 mg)

The maximum dose of lidocaine with epinephrine is 7.0 mg/kg up to a maximum of 500 mg in a healthy adult patient.

Question 87: Retzius lines in enamel represent:

Areas of enamel hypocalcification
Boundaries between primary and secondary enamel
Incremental lines of enamel matrix deposition (Correct answer)
Directions of enamel rod orientation

Correct answer: Incremental lines of enamel matrix deposition

Striae of Retzius are incremental lines in enamel that represent successive layers of enamel matrix deposited during crown formation.

Question 88: Which type of dentin is formed in response to irritation or injury?

Tertiary (reparative) dentin (Correct answer)
Primary dentin
Secondary dentin
Interglobular dentin

Correct answer: Tertiary (reparative) dentin

Tertiary (reparative) dentin is produced by newly differentiated odontoblast-like cells as a protective response to local stimuli such as caries or trauma.

Question 89: The principal fiber group that resists intrusive forces on a tooth is:

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

Correct answer: Oblique fibers

Oblique fibers are the most numerous PDL fibers and are oriented at 45° to resist vertical (intrusive) occlusal forces by converting them into tensile forces on alveolar bone.

Question 90: Canine-protected occlusion refers to:

The canines bearing all lateral excursive contacts while posterior teeth disclude (Correct answer)
Group function on both working and balancing sides
Equal distribution of forces on all teeth in lateral excursion
Immediate posterior disclusion via the anterior teeth

Correct answer: The canines bearing all lateral excursive contacts while posterior teeth disclude

In canine-protected (mutually protected) occlusion, the canines bear and guide all lateral excursive forces, allowing the posterior teeth to disclude and be protected from lateral forces.

Question 91: Secondary caries (recurrent caries) occurs most frequently at which location of an existing restoration?

Pulpal wall
Occlusal surface
Axial wall
Proximal gingival margin (Correct answer)

Correct answer: Proximal gingival margin

The proximal gingival margin is the most common site for recurrent caries due to difficulty in cleaning, plaque accumulation, and microleakage at the cervical margin.

Question 92: A patient on bisphosphonate therapy presents for a dental extraction. The primary concern is:

Drug interaction with local anesthetic
Increased bleeding risk
Medication-related osteonecrosis of the jaw (MRONJ) (Correct answer)
Impaired wound healing due to immunosuppression

Correct answer: Medication-related osteonecrosis of the jaw (MRONJ)

Bisphosphonates inhibit osteoclast activity, impairing bone remodeling and healing, which can lead to MRONJ following invasive dental procedures.

Question 93: Which test is most reliable for diagnosing pulp necrosis?

Thermal cold test
Percussion test
Thermal heat test
Electric pulp test (Correct answer)

Correct answer: Electric pulp test

The electric pulp test (EPT) is used to assess pulp vitality and is most reliable for identifying pulp necrosis; a necrotic pulp will show no response.

Question 94: The Christensen phenomenon describes:

Bennett movement of the condyle
Disclusion of posterior teeth in lateral excursion
Condylar guidance angle's effect on cusp height
The development of a posterior open bite in protrusive movement with balanced occlusion dentures (Correct answer)

Correct answer: The development of a posterior open bite in protrusive movement with balanced occlusion dentures

The Christensen phenomenon is the opening of a wedge-shaped space posteriorly during protrusive movement in complete dentures without balanced occlusion.

Question 95: The neonatal line in primary tooth enamel marks the boundary between:

Enamel and dentin
Prenatal and postnatal enamel (Correct answer)
Outer and inner enamel
Crown and root enamel

Correct answer: Prenatal and postnatal enamel

The neonatal line is a prominent stria of Retzius that marks the junction between prenatally and postnatally formed enamel in primary teeth.

Question 96: The Bonwill triangle in prosthodontics represents:

The angle of the eminence to the Frankfurt horizontal
The relationship between condyles and the incisors forming an equilateral triangle (Correct answer)
The path of condylar movement in protrusion
The cusp height formula for posterior teeth

Correct answer: The relationship between condyles and the incisors forming an equilateral triangle

Bonwill's triangle is an equilateral triangle with 4-inch sides connecting the two condyles and the mesial contact point of the mandibular central incisors.

Question 97: A radiolucent lesion associated with the crown of an unerupted tooth is found on radiograph of a 20-year-old. Histology shows a thin epithelial lining with no dysplasia. What is the diagnosis?

Lateral periodontal cyst
Odontogenic keratocyst
Dentigerous cyst (Correct answer)
Calcifying odontogenic cyst

Correct answer: Dentigerous cyst

A dentigerous cyst (follicular cyst) is the most common developmental odontogenic cyst, enclosing the crown of an unerupted tooth at the cementoenamel junction.

Question 98: The Ramfjord teeth used for periodontal epidemiological studies are:

First molars only
First molars and central incisors
Teeth #3, #9, #12, #19, #25, #28 (Correct answer)
All posterior teeth

Correct answer: Teeth #3, #9, #12, #19, #25, #28

The Ramfjord index teeth (#3, #9, #12, #19, #25, #28) represent all six tooth types and both arches, allowing efficient periodontal assessment in epidemiological surveys.

Question 99: Which property of dental composite resins is most responsible for post-operative sensitivity?

Thermal expansion coefficient mismatch
Polymerization shrinkage creating gap formation (Correct answer)
Lack of fluoride release
Hydrolytic degradation

Correct answer: Polymerization shrinkage creating gap formation

Polymerization shrinkage (1–5% volumetric) creates contraction stress at the bonded margins, leading to gap formation and post-operative sensitivity.

Question 100: Which local anesthetic is safest for a patient with a true amide allergy?

Procaine (Novocain) (Correct answer)
Prilocaine
Mepivacaine
Lidocaine

Correct answer: Procaine (Novocain)

Procaine is an ester-type local anesthetic and can be used in patients with confirmed allergy to amide local anesthetics, as the two classes are chemically distinct.

Question 101: Erythema multiforme most commonly affects young adults and is characterized by which pathognomonic skin lesion?

Wickham's striae
Koebner phenomenon
Target (iris) lesion (Correct answer)
Nikolsky's sign

Correct answer: Target (iris) lesion

The target or iris lesion — concentric rings of erythema — is the hallmark cutaneous lesion of erythema multiforme.

Question 102: Pemphigus vulgaris is caused by autoantibodies directed against which target?

Desmoglein 3 (Correct answer)
Laminin-332
Type VII collagen
BP180 (BPAG2)

Correct answer: Desmoglein 3

Pemphigus vulgaris results from IgG autoantibodies against desmoglein 3 (and desmoglein 1 in skin involvement), disrupting keratinocyte adhesion and causing intraepithelial blistering.

Question 103: Which analgesic is contraindicated in patients with aspirin-exacerbated respiratory disease (AERD)?

Acetaminophen
Tramadol
Ibuprofen (Correct answer)
Codeine

Correct answer: Ibuprofen

NSAIDs like ibuprofen inhibit COX-1, shunting arachidonic acid toward leukotriene production, which triggers bronchoconstriction in patients with AERD.

Question 104: The most critical determinant of the longevity of a dentin bonding agent is:

The pH of the primer
The light intensity of the curing unit
Adequate hybridization of the intertubular dentin (Correct answer)
The number of adhesive layers applied

Correct answer: Adequate hybridization of the intertubular dentin

Hybrid layer formation through resin infiltration into demineralized intertubular dentin is the primary mechanism of dentin bonding and the key determinant of bond durability.

Question 105: Epinephrine is added to local anesthetic solutions primarily to:

Prevent allergic reactions
Decrease the pH of the solution
Prolong the duration of anesthesia by causing vasoconstriction (Correct answer)
Increase the rate of absorption

Correct answer: Prolong the duration of anesthesia by causing vasoconstriction

Epinephrine causes local vasoconstriction, reducing the rate of systemic absorption of the local anesthetic and thereby prolonging its duration and reducing toxicity.

Question 106: Centric relation (CR) is best defined as:

The most superior, anterior position of the condyles in the glenoid fossae (Correct answer)
The most retruded position of the mandible
The position of maximum intercuspation of the teeth
The habitual closure position of the mandible

Correct answer: The most superior, anterior position of the condyles in the glenoid fossae

Centric relation is the maxillomandibular relationship in which the condyles are in their most superior (and slightly anterior) position in the glenoid fossae, independent of tooth contact.

Question 107: Which drug used for seizure management commonly causes gingival enlargement?

Phenobarbital
Valproic acid
Phenytoin (Dilantin) (Correct answer)
Carbamazepine

Correct answer: Phenytoin (Dilantin)

Phenytoin-induced gingival overgrowth occurs in approximately 50% of patients and is related to altered gingival fibroblast metabolism and collagen turnover.

Question 108: Which bacteria is most strongly associated with adult chronic periodontitis?

Fusobacterium nucleatum
Actinomyces viscosus
Streptococcus mutans
Porphyromonas gingivalis (Correct answer)

Correct answer: Porphyromonas gingivalis

Porphyromonas gingivalis is a keystone pathogen in chronic periodontitis, producing virulence factors including gingipains that disrupt the host immune response.

Question 109: Which enzyme found in saliva initiates carbohydrate digestion?

Salivary amylase (ptyalin) (Correct answer)
Lingual lipase
Kallikrein
Lysozyme

Correct answer: Salivary amylase (ptyalin)

Salivary amylase (ptyalin) cleaves alpha-1,4 glycosidic bonds in starch, initiating carbohydrate digestion in the oral cavity.

Question 110: Which bone disease presents radiographically as a 'ground glass' or 'orange peel' appearance and results from replacement of normal bone with fibrous connective tissue?

Fibrous dysplasia (Correct answer)
Paget's disease of bone
Cherubism
Langerhans cell histiocytosis

Correct answer: Fibrous dysplasia

Fibrous dysplasia replaces normal medullary bone with fibrous connective tissue containing woven bone trabeculae, producing the classic ground-glass radiographic pattern.

Question 111: The designation for the glycosylated form of hemoglobin is called:

HbA1c (Correct answer)
HbG
HbC
HbA2

Correct answer: HbA1c

HbA1c is the designation for the glycosylated form of hemoglobin. Normal levels of glycosylated hemoglobin represent about 5% of the total.

Question 112: Fixed partial denture (bridge) pontic designs should ideally contact the residual ridge:

With light contact that can be cleansed (modified ridge lap or ovate) (Correct answer)
With maximum pressure to prevent food impaction
In a broad flat contact (full ridge lap)
Without any contact (sanitary/hygienic pontic)

Correct answer: With light contact that can be cleansed (modified ridge lap or ovate)

The modified ridge lap and ovate pontic designs provide acceptable aesthetics with light tissue contact that can be cleaned, balancing appearance and hygiene.

Question 113: The biologic width refers to the combined measurement of:

Gingival margin to alveolar crest
Sulcus depth and attached gingiva
Free gingival groove to mucogingival junction
Junctional epithelium and connective tissue attachment above the alveolar crest (Correct answer)

Correct answer: Junctional epithelium and connective tissue attachment above the alveolar crest

The biologic width (~2.04 mm) consists of the junctional epithelium (~0.97 mm) and supracrestal connective tissue attachment (~1.07 mm) above the alveolar bone crest.

Question 114: Which medication used for oral sedation has the highest risk of paradoxical excitation in children?

Chloral hydrate
Hydroxyzine
Midazolam (Correct answer)
Diazepam

Correct answer: Midazolam

Midazolam can cause paradoxical reactions (agitation, combativeness, increased anxiety) in approximately 1–15% of pediatric patients.

Question 115: A patient taking a MAO inhibitor should NOT receive which drug?

Meperidine (Demerol) (Correct answer)
Lidocaine
Ibuprofen
Amoxicillin

Correct answer: Meperidine (Demerol)

Meperidine combined with MAO inhibitors can cause a serotonin syndrome, characterized by hyperthermia, seizures, and death.

Question 116: The mucogingival junction (MGJ) is described as the boundary between:

Attached gingiva and alveolar mucosa (Correct answer)
Free and attached gingiva
Junctional epithelium and sulcular epithelium
Gingiva and palatal mucosa

Correct answer: Attached gingiva and alveolar mucosa

The mucogingival junction separates the firmly attached, keratinized attached gingiva from the loose, non-keratinized alveolar mucosa.

Question 117: A facebow transfer records the relationship of:

Vertical dimension of occlusion to rest position
Upper teeth to lower teeth in centric occlusion
Maxillary arch to the transverse hinge axis of the condyles (Correct answer)
Mandible to the Frankfurt horizontal plane

Correct answer: Maxillary arch to the transverse hinge axis of the condyles

A facebow records the spatial relationship of the maxillary arch to the opening axis of the condyles (transverse hinge axis), allowing accurate mounting on an articulator.

Question 118: Which salivary gland tumor is most common overall and is characterized by a biphasic histology with both epithelial and mesenchymal-like components?

Adenoid cystic carcinoma
Pleomorphic adenoma (Correct answer)
Mucoepidermoid carcinoma
Warthin's tumor

Correct answer: Pleomorphic adenoma

Pleomorphic adenoma (mixed tumor) is the most common salivary gland neoplasm, characterized by a mixture of epithelial cells and chondromyxoid stroma.

Question 119: Methemoglobinemia is a rare but serious side effect associated with which local anesthetic?

Bupivacaine
Lidocaine
Articaine
Prilocaine (Correct answer)

Correct answer: Prilocaine

Prilocaine's metabolite o-toluidine oxidizes hemoglobin to methemoglobin; this is clinically significant at doses above 400 mg.

Question 120: Which systemic disease is associated with cyclosporine-induced gingival overgrowth?

Organ transplantation (Correct answer)
Type 1 diabetes
Leukemia
HIV/AIDS

Correct answer: Organ transplantation

Cyclosporine is an immunosuppressant used in organ transplant patients; it causes gingival overgrowth in about 25–30% of patients through altered fibroblast metabolism.

Question 121: What is the primary purpose of acid etching enamel before bonding?

Remove the fluoride-rich surface layer
Create microporosities for micromechanical retention (Correct answer)
Increase the surface energy of dentin
Activate the primer component

Correct answer: Create microporosities for micromechanical retention

Phosphoric acid (30–40%) selectively dissolves enamel hydroxyapatite, creating microporosities that allow resin tags to form and provide micromechanical retention.

Question 122: Which of the following organizations in the United States is responsible for enforcing standard precautions for dental practices, providing guidelines for personal protective equipment, and exposure to bloodborne pathogens.

OSHA (Correct answer)
FDA
EPA
COBRA

Correct answer: OSHA

The organization responsible for enforcing standard precautions for dental practices, providing guidelines for personal protective equipment, and exposure to bloodborne pathogens

Question 123: A 35-year-old female presents with bilateral parotid swelling, dry eyes, and dry mouth. What autoimmune condition should be suspected?

Systemic lupus erythematosus
Rheumatoid arthritis
Sarcoidosis
Sjogren's syndrome (Correct answer)

Correct answer: Sjogren's syndrome

Sjogren's syndrome is an autoimmune exocrinopathy presenting with bilateral parotid enlargement, xerostomia, and keratoconjunctivitis sicca (dry eyes).

Question 124: The disorder referred to as macrocytic anemia is caused by a deficiency in which of the following vitamins?

ascorbate
biotin
folate (Correct answer)
niacin

Correct answer: folate

Macrocytic anemia is caused by a deficiency in folate (folic acid), which is the vitamin component of tetrahydrofolate, THF.

Question 125: Which material is most commonly used as an intracanal medicament between appointments in root canal therapy?

Formocresol
Iodoform paste
Calcium hydroxide (Correct answer)
Zinc oxide eugenol

Correct answer: Calcium hydroxide

Calcium hydroxide is the most widely used intracanal medicament because its high pH (~12.5) is bactericidal, promotes periapical healing, and prevents reinfection between visits.

Question 126: Penicillin V potassium is classified as which type of antibiotic?

Beta-lactam (Correct answer)
Macrolide
Cephalosporin
Aminoglycoside

Correct answer: Beta-lactam

Penicillin V is a beta-lactam antibiotic that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins.

Question 127: Cementum differs from bone primarily because cementum:

Undergoes continuous remodeling
Contains Haversian systems
Is derived from the dental follicle
Is avascular (Correct answer)

Correct answer: Is avascular

Cementum is avascular and receives its nutrition from the periodontal ligament, unlike bone which has its own blood supply via Haversian canals.

Question 128: Which cells are primarily responsible for producing dentin?

Cementoblasts
Ameloblasts
Odontoblasts (Correct answer)
Osteoblasts

Correct answer: Odontoblasts

Odontoblasts are the cells that synthesize and secrete the organic matrix of dentin throughout life.

Question 129: A radiopaque lesion surrounded by a radiolucent halo is found at the root apex of a non-vital tooth in a 30-year-old. What is the most likely diagnosis?

Cementoblastoma (Correct answer)
Periapical ossifying fibroma
Condensing osteitis
Periapical cemento-osseous dysplasia

Correct answer: Cementoblastoma

Cementoblastoma presents as a well-defined radiopaque mass fused to the root of a vital or non-vital tooth, surrounded by a thin radiolucent rim, and often causes expansion.

Question 130: Which type of lichen planus carries the highest risk of malignant transformation?

Plaque-type lichen planus
Papular lichen planus
Reticular lichen planus
Erosive lichen planus (Correct answer)

Correct answer: Erosive lichen planus

Erosive (atrophic/ulcerative) lichen planus has the greatest malignant potential among lichen planus variants, with an estimated 0.5–2% risk of transformation to squamous cell carcinoma.

Question 131: Glass ionomer cement bonds to tooth structure primarily through:

Van der Waals forces
Ionic bonding to calcium in hydroxyapatite (Correct answer)
Micromechanical retention via etching
Chemical bonding to collagen

Correct answer: Ionic bonding to calcium in hydroxyapatite

Glass ionomer cement bonds chemically to tooth structure via ionic interactions between its polyacrylic acid component and calcium and phosphate in hydroxyapatite.

Question 132: A cusp that is fully included within the outer cusp ridges of the opposing arch during maximum intercuspation is classified as a:

Non-supporting cusp (non-centric cusp)
Stamp cusp
Shearing cusp
Supporting cusp (centric holding cusp) (Correct answer)

Correct answer: Supporting cusp (centric holding cusp)

Supporting (centric holding) cusps — maxillary palatal and mandibular buccal — contact the opposing tooth in centric occlusion, maintaining vertical dimension.

Question 133: Which sign is pathognomonic for a draining sinus tract of endodontic origin?

Deepened probing depth at one surface
Radiolucency at the furcation
Parulis (stoma) with tracking to the apex of a non-vital tooth (Correct answer)
Gingival bleeding on probing

Correct answer: Parulis (stoma) with tracking to the apex of a non-vital tooth

A parulis (sinus tract opening/stoma) that tracks with a gutta-percha cone to the apex of a non-vital tooth on radiograph confirms endodontic origin.

Question 134: Osseous surgery in periodontics involves resection of bone to:

Create positive osseous architecture (Correct answer)
Increase attached gingiva
Fill infrabony defects
Stimulate bone regeneration

Correct answer: Create positive osseous architecture

Positive osseous architecture (where interproximal bone is higher than facial/lingual bone) is the physiologic ideal achieved through osteoplasty and ostectomy.

Question 135: Which salivary gland produces the most serous secretion?

Submandibular gland
Minor labial glands
Parotid gland (Correct answer)
Sublingual gland

Correct answer: Parotid gland

The parotid gland is entirely serous and produces a watery, enzyme-rich (amylase) secretion comprising about 25% of total saliva volume.

Question 136: Scaling and root planing (SRP) is most accurately described as:

Prophylactic polishing of root surfaces
Removal of calculus and contaminated cementum with root smoothing (Correct answer)
Removal of all cementum from root surfaces
Surgical debridement of the periodontium

Correct answer: Removal of calculus and contaminated cementum with root smoothing

SRP involves removal of supragingival and subgingival calculus, contaminated cementum, and plaque from root surfaces to create a biologically acceptable root surface.

Question 137: A painless, lobulated mass arising from the interdental papilla with a pedunculated base is found in a 28-year-old pregnant woman. What is the most likely diagnosis?

Fibroma
Peripheral ossifying fibroma
Pyogenic granuloma (Correct answer)
Giant cell granuloma

Correct answer: Pyogenic granuloma

Pyogenic granuloma (pregnancy tumor/epulis gravidarum) is a highly vascular reactive lesion that commonly arises from the gingival papilla and is exacerbated by hormonal changes during pregnancy.

Question 138: Necrotizing ulcerative gingivitis (NUG) is characterized by:

Deep periodontal pockets with bone loss
Furcation involvement in molars
Punched-out interdental papillae, pseudomembrane, and fetid breath (Correct answer)
Generalized gingival recession

Correct answer: Punched-out interdental papillae, pseudomembrane, and fetid breath

NUG presents with necrosis and ulceration of interdental papillae (giving a 'punched-out' appearance), a gray pseudomembrane, fetid breath, and pain.

Question 139: A painless, slow-growing mass at the angle of the mandible in a 60-year-old is found to contain perineural invasion on biopsy. Which salivary gland tumor is most likely?

Adenoid cystic carcinoma (Correct answer)
Acinic cell carcinoma
Pleomorphic adenoma
Warthin's tumor

Correct answer: Adenoid cystic carcinoma

Adenoid cystic carcinoma is notorious for perineural invasion and spread, explaining pain or facial nerve symptoms despite its deceptively slow growth.

Question 140: Heparin is a rapidly acting, potent anticoagulant that has many important clinical uses. Which of the following is an action of heparin?

decreases prothrombin time
activates prothrombin
inhibits calcium action
acts with antithrombin III to inhibit thrombin activity (Correct answer)

Correct answer: acts with antithrombin III to inhibit thrombin activity

Heparin acts as an anticoagulant because it accelerates the action of antithrombin III to inhibit thrombin activity.

Question 141: Medicare Part: B Coverage: ?

Outpatient medical coverage (Correct answer)
Prescription medication
Inpatient or hospital based coverage
Inpatient or hospital based coverage

Correct answer: Outpatient medical coverage

This is the correct choice for Medicare Part B coverage. Part B primarily covers outpatient medical services, including doctor visits, diagnostic tests, preventive care, durable medical equipment, and some home health services.

Question 142: Guided tissue regeneration (GTR) works by:

Stimulating bone formation with growth factors
Applying enamel matrix proteins to the root surface
Grafting autogenous bone into the defect
Excluding epithelium and allowing periodontal ligament cells to repopulate the root surface (Correct answer)

Correct answer: Excluding epithelium and allowing periodontal ligament cells to repopulate the root surface

GTR uses barrier membranes to prevent fast-growing epithelial and gingival connective tissue cells from occupying the defect space, allowing slower PDL and bone cells to regenerate.

Question 143: Dead tracts in dentin appear black in transmitted light because they contain:

Bacteria
Secondary dentin
Blood pigments
Air (Correct answer)

Correct answer: Air

Dead tracts are areas where odontoblastic processes have degenerated and the empty dentinal tubules become filled with air, causing them to appear dark in transmitted light.

Question 144: Which benzodiazepine is most commonly used for IV conscious sedation in dentistry?

Diazepam
Lorazepam
Midazolam (Correct answer)
Triazolam

Correct answer: Midazolam

Midazolam is preferred for IV conscious sedation in dentistry due to its rapid onset, short duration, water solubility, and superior amnestic properties.

Question 145: A patient presents with a blue, dome-shaped, fluctuant lesion on the floor of the mouth that displaces the tongue. What is the most likely diagnosis?

Mucocele
Dermoid cyst
Lymphoepithelial cyst
Ranula (Correct answer)

Correct answer: Ranula

A ranula is a mucus-retention or extravasation phenomenon arising from the sublingual or submandibular salivary glands, presenting as a blue, fluctuant swelling on the floor of the mouth.

Question 146: Obesity, genetic profile, and aging all contribute to the development of Type II diabetes. Of the following, which is the most important additive factor for these three conditions in the development of Type II diabetes?

muscle resistance to insulin (Correct answer)
elevated pancreatic glucagon secretion
impaired renal clearance of glucose
elevated hepatic ketogenesis

Correct answer: muscle resistance to insulin

Muscle resistance to insulin is the most important additive factor for these three conditions in the development of Type II diabetes. Progressive loss of skeletal muscle sensitivity to insulin leads to increased rates of visceral cell lipolysis and pancreatic betA-cell compensation.

Question 147: Medicare Part: D Coverage: ?

Holistic medication
Prescription medication (Correct answer)
Physical therapy
Engineering control

Correct answer: Prescription medication

Medicare Part D is the part of Medicare that provides coverage for prescription drugs. This plan helps Medicare beneficiaries pay for the medications prescribed by their doctors, reducing out-of-pocket costs for both brand-name and generic drugs.

Question 148: Which zone of the dental pulp contains the highest concentration of collagen fibers?

Odontoblastic zone
Cell-free zone of Weil
Pulp core (Correct answer)
Cell-rich zone

Correct answer: Pulp core

The pulp core (central zone) contains the largest blood vessels and nerves and has the highest density of collagen fibers.

Question 149: Which of the following organizations should be contacted about the safety of the dental laser?

American Dental Association (ADA)
Centers for Disease Control and Prevention (CDC)
Food and Drug Administration (FDA) (Correct answer)
Occupational Health and Safety Administration (OSHA)

Correct answer: Food and Drug Administration (FDA)

The FDA is responsible for regulating medical devices, including dental lasers, to ensure their safety and effectiveness.

Question 150: Post-exposure blood testing routinely tests for

should be treated in an airborne infection isolation room.
Inpatient or hospital based coverage
hepatitis B, hepatitis C and human immunodeficiency virus. (Correct answer)
heat and moisture-sensitive medical and dental equipment.

Correct answer: hepatitis B, hepatitis C and human immunodeficiency virus.

Post-exposure blood testing routinely tests

Question 151: About 75% of the blood supply of the spinal cord is derived from the anterior spinal artery. This artery originates from which of the following?

Internal carotid artery
Vertebral artery (Correct answer)
Basilar artery
Posterior inferior cerebellar artery

Correct answer: Vertebral artery

The anterior spinal artery is a small branch, which arises near the termination of the vertebral, and, descending in front of the medulla oblongata, unites with its fellow of the opposite side at the level of the foramen magnum.

Integrated National Board Dental Examination (INBDE)

The INBDE is a two-day, 500-question dental licensure examination administered by the Joint Commission on National Dental Examinations (JCNDE/ADA), assessing candidates' ability to integrate biomedical, clinical, and behavioral sciences to make patient-centered clinical decisions required for safe, entry-level general dental practice.

500

Questions

750 min

Time Limit

75%

To Pass

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Unanswered questions count as wrong — answer everything
10 pretest questions are mixed in and don't affect your score
Timer auto-submits when time runs out
Your progress is auto-saved every 30 seconds