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

Question 1: After a 40-pack-year smoking history, a patient expresses a wish to quit. Except for one, all of the following would be proper actions. Which of these is an EXCEPTION?

Recommend use of a smokeless tobacco (Correct answer)
Recommend nicotine (Nicorette®) chewing gum
Prescribe a nicotine (NicoDerm-CQ®) patch
Recommend hypnosis

Correct answer: Recommend use of a smokeless tobacco

Recommending smokeless tobacco is not a proper action for a patient wishing to quit smoking. While smokeless tobacco eliminates some risks associated with combustion, it still contains nicotine and numerous carcinogens, posing significant health risks including oral cancer, periodontal disease, and nicotine addiction. The goal of tobacco cessation counseling is complete abstinence from all tobacco products.

Question 2: Central giant cell granuloma of the jaw is histologically characterized by:

Ameloblast-like cells lining a cystic cavity
Multinucleated giant cells in a fibrous connective tissue stroma (Correct answer)
Calcified deposits within spindle cell stroma
Sheets of basaloid cells with peripheral palisading

Correct answer: Multinucleated giant cells in a fibrous connective tissue stroma

CGCG shows numerous osteoclast-like multinucleated giant cells dispersed within a vascular fibrous stroma, often with hemosiderin deposits.

Question 3: Porphyromonas gingivalis is a key periodontal pathogen primarily because it:

Produces fluoride that damages enamel
Is exclusively found in healthy gingival sulci
Produces virulence factors including gingipains and lipopolysaccharides (Correct answer)
Is a Gram-positive facultative aerobe

Correct answer: Produces virulence factors including gingipains and lipopolysaccharides

P. gingivalis is a Gram-negative anaerobe that secretes gingipain proteases and LPS, enabling it to evade host defenses and drive connective tissue destruction.

Question 4: Bundle bone in the alveolar process is characterized by:

Absence of blood vessels
Lamellar structure parallel to the alveolar crest
Sharpey's fiber insertions from the PDL into the bone (Correct answer)
High density of osteocytes without fiber insertions

Correct answer: Sharpey's fiber insertions from the PDL into the bone

Bundle bone is the alveolar bone proper that lines the tooth socket and is named for the bundles of Sharpey's fibers (PDL principal fibers) inserting into it.

Question 5: An autogenous bone graft used in periodontal surgery is defined as bone harvested from:

An animal source
A human cadaver
A synthetic calcium phosphate material
The patient's own body (Correct answer)

Correct answer: The patient's own body

Autogenous grafts are taken from the patient (e.g., maxillary tuberosity, chin, or ramus) and are considered the gold standard because they are osteogenic, osteoinductive, and osteoconductive.

Question 6: Which local anesthetic has the longest duration of action among those used in dentistry?

Prilocaine
Bupivacaine (Correct answer)
Lidocaine
Mepivacaine

Correct answer: Bupivacaine

Bupivacaine (Marcaine) has the longest duration of action, providing pulpal anesthesia for up to 90 minutes and soft-tissue anesthesia for 4–9 hours.

Question 7: Which antibiotic is the first-line choice for prophylaxis against infective endocarditis before dental procedures in eligible patients?

Penicillin VK 500 mg orally twice daily for 5 days
Azithromycin 500 mg orally the night before
Clindamycin 600 mg orally 1 hour before the procedure
Amoxicillin 2 g orally 30–60 minutes before the procedure (Correct answer)

Correct answer: Amoxicillin 2 g orally 30–60 minutes before the procedure

Current AHA guidelines recommend amoxicillin 2 g (adults) orally 30–60 minutes before procedures as first-line IE prophylaxis for eligible high-risk patients.

Question 8: When using the 'lost wax' technique in dental casting, the wax is eliminated during which step?

Burnout (Correct answer)
Casting
Spruing
Investing

Correct answer: Burnout

During burnout, the invested ring is heated in a furnace to completely eliminate (burn out) the wax pattern, creating a mold space for the molten metal.

Question 9: Which systemic condition is most closely associated with an increased risk of dry socket (alveolar osteitis) after tooth extraction?

Cigarette smoking (Correct answer)
Hypertension
Diabetes mellitus
Hypothyroidism

Correct answer: Cigarette smoking

Cigarette smoking significantly increases the risk of dry socket by inhibiting clot formation and promoting fibrinolysis through vasoconstriction and chemical interference from tobacco.

Question 10: Guided tissue regeneration (GTR) barrier membranes function by:

Preventing bacterial contamination of the surgical site
Providing structural support to damaged alveolar bone
Stimulating osteoclast-mediated bone remodeling
Excluding epithelial and gingival connective tissue cells from the healing wound (Correct answer)

Correct answer: Excluding epithelial and gingival connective tissue cells from the healing wound

GTR membranes selectively block fast-migrating epithelial and connective tissue cells, allowing slower-growing PDL and bone cells to repopulate the defect for true regeneration.

Question 11: Which condition is characterized by numerous odontogenic keratocysts, basal cell carcinomas of the skin, and skeletal anomalies?

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

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 12: OSHA's bloodborne pathogen standard mandates healthcare. EXCEPT for one, employers must perform all of the following. Which is it? WHAT IS THE EXCEPTION?

Establish an exposure control plan.
Make hepatitis C vaccinations available. (Correct answer)
Provide personal protective equipment.
Implement the use of standard precautions.

Correct answer: Make hepatitis C vaccinations available.

OSHA's Bloodborne Pathogens Standard mandates employers to provide hepatitis B vaccinations to employees at risk of occupational exposure. However, there is currently no vaccine available for hepatitis C, so employers cannot be mandated to make it available. The other options (providing personal protective equipment, implementing standard precautions, and establishing an exposure control plan) are all required by the standard.

Question 13: Which tooth structure is formed last during tooth development?

Dentin
Pulp
Enamel
Cementum (Correct answer)

Correct answer: Cementum

Cementum is deposited by cementoblasts after root formation begins, which occurs after enamel and dentin have already been laid down by ameloblasts and odontoblasts.

Question 14: Which layer of enamel is formed first during tooth development?

Inner enamel layer (Correct answer)
Striae of Retzius
Outer enamel layer
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 15: When taking a full-mouth series of periapical radiographs, the paralleling technique is preferred over bisecting angle because it:

Is easier to perform on patients with small mouths
Requires fewer films
Produces less image distortion and more accurate representation (Correct answer)
Requires less radiation exposure

Correct answer: Produces less image distortion and more accurate representation

The paralleling technique minimizes geometric distortion because the film is parallel to the tooth's long axis and the X-ray beam is perpendicular to both.

Question 16: When administering a Gow-Gates mandibular nerve block, the target landmark for needle placement is:

The neck of the mandibular condyle, below the lateral pterygoid muscle insertion (Correct answer)
The pterygomandibular raphe midpoint
The anterior border of the ramus at the coronoid notch
The mandibular foramen on the medial ramus

Correct answer: The neck of the mandibular condyle, below the lateral pterygoid muscle insertion

The Gow-Gates technique targets the condylar neck, anesthetizing the entire mandibular nerve division (V3) at a single high injection point.

Question 17: Which local anesthetic is CONTRAINDICATED in a patient with a documented allergy to para-aminobenzoic acid (PABA) derivatives?

Mepivacaine
Procaine (Correct answer)
Bupivacaine
Lidocaine

Correct answer: Procaine

Procaine is an ester-type anesthetic that is metabolized to PABA, making it contraindicated in patients with PABA allergies.

Question 18: A patient presents with a fractured maxillary central incisor involving the pulp. The tooth is fully developed with a closed apex. What is the most appropriate initial treatment?

Direct pulp capping with MTA
Root canal treatment (Correct answer)
Pulpotomy
Extraction and implant placement

Correct answer: Root canal treatment

A fully developed tooth with pulp exposure from trauma is best treated with root canal therapy to prevent infection and preserve the tooth.

Question 19: A patient undergoing extraction requires anticoagulation management. Their INR is 2.8. What is the best course of action?

Postpone extraction until INR is below 1.5
Administer vitamin K to reverse anticoagulation
Consult physician to stop anticoagulants 5 days before
Proceed with extraction using local hemostatic measures (Correct answer)

Correct answer: Proceed with extraction using local hemostatic measures

Current evidence supports proceeding with dental extractions when INR is ≤3.5 using local hemostatic measures, avoiding systemic anticoagulation reversal.

Question 20: 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 21: Which radiographic view is best for evaluating the condylar head and the temporomandibular joint space?

Waters' view
Lateral cephalogram
Panoramic radiograph
Transcranial radiograph (Correct answer)

Correct answer: Transcranial radiograph

The transcranial (lateral oblique) projection provides a useful view of the lateral aspect of the condylar head and the joint space.

Question 22: Which of the following screening radiographs would be most useful in determining a fracture of the mandible?

Panoramic (Correct answer)
Periapical
Bitewing
Bitewing

Correct answer: Panoramic

A panoramic radiograph provides a broad, comprehensive view of the entire mandible, maxilla, and associated structures. This wide field of view makes it an excellent screening tool for detecting mandibular fractures, as it can show the extent and location of breaks that might be missed on smaller, localized films like periapicals or bitewings.

Question 23: Which fibers of the periodontal ligament embed directly into the cementum and alveolar bone?

Oxytalan fibers
Sharpey's fibers (Correct answer)
Reticular fibers
Elastic fibers

Correct answer: Sharpey's fibers

Sharpey's fibers are the terminal portions of principal periodontal ligament fibers that insert into cementum and alveolar bone, anchoring the tooth in its socket.

Question 24: A ferrule effect in crown preparation refers to:

Encirclement of sound tooth structure above the cement margin by the crown walls (Correct answer)
Using dual-cure cement to bond the crown to dentin
The creation of a 1 mm shoulder preparation at the gingival finish line
The use of a chamfer finish line to guide die-spacer application

Correct answer: Encirclement of sound tooth structure above the cement margin by the crown walls

The ferrule is a band of sound coronal tooth structure between the preparation finish line and the core, encircled by the crown, which provides anti-fracture resistance to root stress.

Question 25: Which type of connector joins two or more retainers in a fixed partial denture?

Rest seat
Rigid connector (Correct answer)
Pontic
Major connector

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.

Question 26: Which microorganism is considered the primary etiological agent in the initiation of dental caries?

Actinomyces viscosus
Streptococcus salivarius
Lactobacillus acidophilus
Streptococcus mutans (Correct answer)

Correct answer: Streptococcus mutans

Streptococcus mutans is the principal organism initiating dental caries due to its high acidogenic and aciduric properties and ability to produce glucan for biofilm adherence.

Question 27: Pulp therapy for a carious primary molar with a normal radiograph and no spontaneous pain, but mechanical pulp exposure, is best treated by:

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

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 28: In the mixed dentition, the ugly duckling stage is characterized by:

Anterior crossbite of the permanent central incisors
Excessive crowding of the mandibular anterior teeth
Class III molar relationship during canine eruption
Spacing between the maxillary central incisors due to lateral incisor and canine pressure on the roots (Correct answer)

Correct answer: Spacing between the maxillary central incisors due to lateral incisor and canine pressure on the roots

The ugly duckling stage occurs when erupting permanent lateral incisors and canines press on the roots of the centrals, causing them to flare and create a midline diastema that self-corrects on canine eruption.

Question 29: Which systemic disease has the strongest bidirectional relationship with periodontitis?

Asthma
Diabetes mellitus (Correct answer)
Hypothyroidism
Hypertension

Correct answer: Diabetes mellitus

Poorly controlled diabetes impairs neutrophil function and collagen metabolism, worsening periodontitis; conversely, periodontal infection raises blood glucose levels.

Question 30: The smear layer created during cavity preparation:

Can be modified or removed depending on the bonding system (total-etch vs. self-etch) (Correct answer)
Has no effect on the bond strength of glass ionomer cements
Improves adhesion of all bonding systems equally
Must always be completely removed before bonding

Correct answer: Can be modified or removed depending on the bonding system (total-etch vs. self-etch)

Total-etch systems remove the smear layer with phosphoric acid before priming, while self-etch systems incorporate and modify (but don't remove) the smear layer during bonding.

Question 31: When taking a full-arch alginate impression, saliva contamination most commonly causes which problem?

Premature alginate gelation
Permanent distortion of the tray material
Surface porosity and voids in the impression due to hydrophilicity disruption (Correct answer)
Excessive detail in the soft tissue areas

Correct answer: Surface porosity and voids in the impression due to hydrophilicity disruption

Saliva on the tissue surface creates bubbles and interferes with alginate flow, producing surface voids and loss of detail in the final impression.

Question 32: A patient presents with painless, bluish swelling on the floor of the mouth that fluctuates. The most likely diagnosis is:

Ranula (Correct answer)
Mucocele
Ludwig's angina
Dermoid cyst

Correct answer: Ranula

A ranula is a mucous retention phenomenon or extravasation cyst arising from the sublingual gland, presenting as a bluish, fluctuant swelling on the floor of the mouth.

Question 33: The recommended fluoride concentration in community water fluoridation as updated by the US Department of Health and Human Services (HHS) is:

0.7 ppm (Correct answer)
1.0 ppm
0.5 ppm
1.2 ppm

Correct answer: 0.7 ppm

In 2015, HHS revised the recommended community water fluoride concentration to 0.7 mg/L (ppm) nationwide, down from the previous range of 0.7–1.2 ppm.

Question 34: Which benzodiazepine reversal agent should be available when administering IV conscious sedation in dentistry?

Flumazenil (Romazicon) (Correct answer)
Protamine sulfate
Physostigmine
Naloxone (Narcan)

Correct answer: Flumazenil (Romazicon)

Flumazenil is a competitive benzodiazepine receptor antagonist that reverses sedation and respiratory depression caused by benzodiazepines used in IV sedation.

Question 35: Which enamel developmental defect results from high fevers during amelogenesis and appears as horizontal lines across affected teeth?

Enamel hypocalcification
Fluorosis
Chronological hypoplasia (Correct answer)
Enamel hypoplasia (Turner's tooth)

Correct answer: Chronological hypoplasia

Chronological (systemic) hypoplasia results from systemic disturbances (fever, illness, malnutrition) during amelogenesis, producing horizontal bands across the affected dentition.

Question 36: Which restorative material has the highest compressive strength and is most indicated for posterior stress-bearing restorations?

Amalgam (Correct answer)
Composite resin
Glass ionomer cement
Zinc phosphate cement

Correct answer: Amalgam

Dental amalgam has compressive strength of approximately 380–550 MPa, superior to composites and glass ionomers, making it durable for load-bearing posterior restorations.

Question 37: The normal overjet (horizontal overlap) in a Class I occlusion is approximately:

6–8 mm
1 mm or negative
2–4 mm (Correct answer)
0 mm (edge-to-edge)

Correct answer: 2–4 mm

Normal overjet in a Class I occlusion ranges from 2–4 mm, representing the horizontal distance between the facial surface of the lower incisors and the lingual surface of the upper incisors.

Question 38: The Angle Class II, Division 2 malocclusion is characterized by which combination of features?

Anterior crossbite with normal molar relationship
Protruded maxillary incisors and distal molar relationship
Retroclined maxillary central incisors and distal molar relationship (Correct answer)
Mesial molar relationship with crowding

Correct answer: Retroclined maxillary central incisors and distal molar relationship

Class II Division 2 features a distal molar relationship with retroclined (not protruded) maxillary central incisors and a deep overbite.

Question 39: Which drug is used to reverse soft tissue anesthesia after dental procedures by antagonizing epinephrine's vasoconstriction?

Phentolamine mesylate (OraVerse) (Correct answer)
Naloxone
Atropine
Flumazenil

Correct answer: Phentolamine mesylate (OraVerse)

Phentolamine mesylate (OraVerse) is an alpha-adrenergic antagonist injected after dental procedures to reverse epinephrine-mediated vasoconstriction and accelerate return of normal sensation.

Question 40: Molar-incisor hypomineralization (MIH) affects which teeth?

First permanent molars and permanent incisors (Correct answer)
All permanent posterior teeth
All primary molars and primary incisors
Second permanent molars and canines

Correct answer: First permanent molars and permanent incisors

MIH is defined by demarcated qualitative enamel defects affecting one to four first permanent molars, frequently accompanied by affected permanent incisors.

Question 41: During composite resin placement, the dentist uses an incremental layering technique. The primary reason for this technique is to:

Improve color matching
Increase working time
Reduce polymerization shrinkage stress (Correct answer)
Avoid the need for a bonding agent

Correct answer: Reduce polymerization shrinkage stress

Incremental layering reduces the overall polymerization shrinkage stress by limiting the volume of composite cured at one time and allowing stress relief.

Question 42: Which condition is characterized by failure of cementum to cover the root apex, resulting in exposed dentin at the apex?

Hypercementosis
Taurodontism
Dilaceration
Cemental aplasia (Correct answer)

Correct answer: Cemental aplasia

Cemental aplasia refers to absent or deficient cementum at the root apex, leaving dentin exposed and potentially causing hypersensitivity or periodontal vulnerability.

Question 43: Methemoglobinemia is a specific adverse effect associated with which local anesthetic?

Articaine
Prilocaine (Correct answer)
Lidocaine
Bupivacaine

Correct answer: Prilocaine

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

Question 44: What is the scientific name of the primary pathogen responsible for early childhood caries (ECC)?

Streptococcus salivarius
Lactobacillus acidophilus
Actinomyces viscosus
Streptococcus mutans (Correct answer)

Correct answer: Streptococcus mutans

Streptococcus mutans is the principal bacterium responsible for early childhood caries due to its ability to produce lactic acid and adhere to tooth surfaces via glucans.

Question 45: Which odontogenic cyst is most commonly associated with an impacted mandibular third molar?

Odontogenic keratocyst
Dentigerous cyst (Correct answer)
Radicular cyst
Lateral periodontal cyst

Correct answer: Dentigerous cyst

The dentigerous (follicular) cyst forms by fluid accumulation between the crown of an impacted tooth and its reduced enamel epithelium, most frequently around mandibular third molars.

Question 46: What is the hardest substance in the human body?

Cortical bone
Enamel (Correct answer)
Dentin
Cementum

Correct answer: Enamel

Dental enamel is the hardest biological material in the human body, composed of approximately 96% hydroxyapatite mineral by weight.

Question 47: Which cell type is primarily responsible for alveolar bone resorption in periodontitis?

Cementoblasts
Osteoblasts
Fibroblasts
Osteoclasts (Correct answer)

Correct answer: Osteoclasts

Osteoclasts are multinucleated cells derived from monocyte precursors that resorb bone via acids and proteolytic enzymes in response to inflammatory cytokines.

Question 48: Which of the following should you do before taking out tooth 24?

Clarithromycin (Biaxin®) 500 milligrams should be taken 30 minutes to 60 minutes before procedure.
No antibiotic administration is required.
Warfarin (Coumadin®) should be discontinued the morning before procedure.
Amoxicillin 2 grams should be taken 30 minutes to 60 minutes before procedure. (Correct answer)

Correct answer: Amoxicillin 2 grams should be taken 30 minutes to 60 minutes before procedure.

Tooth 24 is a mandibular incisor. Antibiotic prophylaxis is indicated for patients at high risk of infective endocarditis undergoing dental procedures that involve manipulation of gingival tissue or the periapical region of teeth. Amoxicillin 2 grams orally 30-60 minutes before the procedure is the standard prophylactic regimen for such patients, according to American Heart Association guidelines.

Question 49: Reimplantation is preferred. After avulsion, how can permanent teeth be effectively shielded?

Wrap in a wet napkin
Put in a cup of milk
Place under the tongue
Place back into the sockets (Correct answer)

Correct answer: Place back into the sockets

For an avulsed permanent tooth, the most effective way to preserve its viability and maximize the chances of successful reimplantation is to immediately place it back into its socket. This maintains the periodontal ligament cells in their natural environment, which is critical for healing. If immediate replantation isn't possible, storage in milk or saline is recommended as a temporary measure.

Question 50: The wax-up of a complete denture is evaluated and the occlusal plane is found to be slanting downward on the right side. Which adjustment corrects this?

Remount and re-evaluate vertical dimension
Raise the posterior teeth on the left side
Rotate the occlusal plane by adjusting incisal guidance
Lower the posterior teeth on the right side (Correct answer)

Correct answer: Lower the posterior teeth on the right side

Lowering the right posterior teeth corrects the canting of the occlusal plane that slopes downward to the right.

Question 51: In a healthy periodontium, the apical termination of the junctional epithelium coincides with the:

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

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 52: Which type of enamel rod orientation is found in the cervical third of the crown?

Rods are randomly arranged
Rods run horizontally
Rods incline occlusally
Rods incline cervically (apically) (Correct answer)

Correct answer: Rods incline cervically (apically)

In the cervical third, enamel rods incline apically (cervically), which is important when performing cavity preparation to avoid undermined enamel.

Question 53: Which medication class is most likely to cause gingival hyperplasia as a side effect?

ACE inhibitors
Tetracyclines
Calcium channel blockers (Correct answer)
Beta-blockers

Correct answer: Calcium channel blockers

Calcium channel blockers (e.g., nifedipine, amlodipine) are well-documented causes of drug-induced gingival overgrowth, along with phenytoin and cyclosporine.

Question 54: What is considered the primary etiologic factor initiating periodontal disease?

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

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 55: What is the primary organic component of mature enamel?

Tuftelin
Enamelin (Correct answer)
Amelogenin
Ameloblastin

Correct answer: Enamelin

Enamelin constitutes the main organic protein retained in fully mature enamel, whereas amelogenin is largely removed during maturation.

Question 56: Which gland produces the largest volume of saliva under resting (unstimulated) conditions?

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

Correct answer: Submandibular gland

The submandibular gland contributes approximately 60–65% of unstimulated salivary flow, making it the dominant resting-state salivary gland.

Question 57: Which cement provides the best seal against microleakage when used as a base under amalgam restorations?

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

Correct answer: Glass ionomer cement

Glass ionomer cements bond chemically to tooth structure, release fluoride, and exhibit minimal microleakage, making them superior bases/liners under amalgam.

Question 58: Ameloblastoma is most commonly located in which area of the jaw?

Anterior mandible
Anterior maxilla
Posterior mandible (molar-ramus region) (Correct answer)
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 59: The gubernacular canal in the jaw bone transmits which structure during tooth eruption?

Lymphatics draining the developing tooth
Nerve fibers of the inferior alveolar nerve
Blood vessels supplying the dental follicle
The gubernacular cord connecting follicle to oral epithelium (Correct answer)

Correct answer: The gubernacular cord connecting follicle to oral epithelium

The gubernacular cord, a fibrous band connecting the dental follicle to the overlying oral epithelium, passes through the gubernacular canal to guide eruption.

Question 60: A child presents with a completely avulsed permanent incisor. The best immediate storage medium before replantation is:

Tap water
Saline only
Hank's Balanced Salt Solution (HBSS) or milk (Correct answer)
Dry storage in a tissue or napkin

Correct answer: Hank's Balanced Salt Solution (HBSS) or milk

HBSS (save-a-tooth solution) is the gold standard storage medium; milk is the best readily available alternative due to appropriate osmolarity and nutrients that maintain PDL cell viability.

Question 61: The chronological age at which the human primary dentition is typically complete (all 20 primary teeth erupted) is approximately:

36–42 months
24–30 months (Correct answer)
48–54 months
12–18 months

Correct answer: 24–30 months

The primary dentition is typically complete by approximately 24–30 months of age when the second primary molars erupt, completing the 20-tooth primary dentition.

Question 62: Rests of Malassez are remnants of which structure found in the periodontal ligament?

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

Correct answer: Hertwig's epithelial root sheath

After root formation, Hertwig's sheath disintegrates and leaves behind epithelial cell clusters called rests of Malassez within the PDL.

Question 63: How many crystalloid infusions are necessary for 100 cc of blood loss?

200 cc
400 cc
300 cc (Correct answer)
100 cc

Correct answer: 300 cc

The general guideline for fluid resuscitation in cases of blood loss is to administer crystalloid solutions at a 3:1 ratio. This means for every 100 cc of blood lost, approximately 300 cc of crystalloid fluid (such as normal saline or lactated Ringer's) should be infused. This ratio accounts for the rapid redistribution of crystalloids out of the intravascular space into the interstitial fluid.

Question 64: The junction between enamel and dentin is characteristically scalloped to:

Increase surface area for diffusion of nutrients
Provide a pathway for enamel spindles
Prevent enamel fracture by interlocking the two tissues (Correct answer)
Allow passage of odontoblast processes into enamel

Correct answer: Prevent enamel fracture by interlocking the two tissues

The scalloped DEJ interdigitates enamel and dentin so that forces transmitted to enamel are distributed broadly, reducing crack propagation.

Question 65: Mandibular nerve block using a closed mouth technique?

Akinosi method (Correct answer)
None
Gow-gates technique
Both

Correct answer: Akinosi method

The Akinosi method, also known as the Vazirani-Akinosi closed-mouth mandibular nerve block, is performed with the patient's mouth closed or only partially open. This technique is particularly advantageous for patients who have difficulty opening their mouths due to conditions like trismus. It targets the inferior alveolar, lingual, and buccal nerves from a medial approach.

Question 66: Which radiographic technique is best suited for detecting interproximal caries in posterior teeth?

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

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 67: A patient complains of severe, spontaneous, lancinating pain along the right cheek that lasts seconds and is triggered by eating. There is no neurologic deficit. This presentation is most consistent with:

Atypical facial pain
Temporomandibular disorder
Cluster headache
Trigeminal neuralgia (Correct answer)

Correct answer: Trigeminal neuralgia

Trigeminal neuralgia is characterized by sudden, severe, unilateral lancinating facial pain often triggered by routine activities like eating or touching the face.

Question 68: Which cranial nerve is responsible for the general sensory innervation of the teeth and gums?

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

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 69: The needle is moved toward the condyle's neck in?

Akinosi method
Gow-gates technique (Correct answer)
Inferior alveolar block
All

Correct answer: Gow-gates technique

The Gow-Gates technique is a comprehensive mandibular nerve block where the anesthetic solution is deposited near the neck of the condyle. This approach aims to anesthetize the entire V3 division of the trigeminal nerve, providing widespread anesthesia to the mandibular teeth, buccal soft tissues, and tongue. Its target site is superior and posterior to the traditional inferior alveolar nerve block.

Question 70: Miller's Class I gingival recession is defined as:

Recession extending to the mucogingival junction with no interproximal bone loss
Recession extending beyond the mucogingival junction without interproximal bone loss
Recession not extending to or beyond the mucogingival junction with no interproximal bone or soft tissue loss (Correct answer)
Recession extending beyond the mucogingival junction with interproximal bone loss

Correct answer: Recession not extending to or beyond the mucogingival junction with no interproximal bone or soft tissue loss

Miller Class I recession does not reach the mucogingival junction and there is no interproximal bone or soft tissue loss; complete root coverage is predictably achievable.

Question 71: Which of the following ASA classifications applies to a patient who's under threat to life?

1
4 (Correct answer)
3
5

Correct answer: 4

The American Society of Anesthesiologists (ASA) Physical Status Classification System assesses a patient's overall health before surgery. An ASA Class 4 patient is defined as having a severe systemic disease that is a constant threat to life. This classification indicates a high risk for anesthesia and surgical procedures.

Question 72: Pemphigus vulgaris involves oral mucosa due to autoantibodies directed against:

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

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 73: A dentist notices gingival fibromatosis in a patient taking which medication?

Metformin
Prednisone
Amlodipine
Phenytoin (Correct answer)

Correct answer: Phenytoin

Phenytoin (Dilantin), an anticonvulsant, is one of the classic causes of drug-induced gingival overgrowth (fibromatosis) along with cyclosporine and calcium channel blockers.

Question 74: The 'rule of 1s' in local anesthesia refers to which landmark for inferior alveolar nerve blocks?

1 cm distal to the last mandibular molar
1 mm below the coronoid notch
1 mm anterior to the pterygomandibular raphe
1 cm above the occlusal plane of the mandibular molars (Correct answer)

Correct answer: 1 cm above the occlusal plane of the mandibular molars

The target for the inferior alveolar nerve block is approximately 1 cm (or one fingerbreadth) above the occlusal plane of the mandibular molars at the medial ramus.

Question 75: In guided tissue regeneration, which of the following cell populations is the main progenitor for a new connective tissue attachment?

Cell rests of Malassez
Alveolar bone stem cells
Periodontal ligament fibroblasts (Correct answer)
Gingival fibroblasts

Correct answer: Periodontal ligament fibroblasts

In guided tissue regeneration (GTR), periodontal ligament (PDL) fibroblasts are crucial because they possess the capacity to differentiate into cementoblasts and osteoblasts. These cells are essential for forming new cementum, periodontal ligament, and alveolar bone, which collectively constitute a new functional connective tissue attachment. Other cell types like gingival fibroblasts would lead to epithelial downgrowth or scar tissue, not true regeneration of the attachment apparatus.

Question 76: The caries-detecting dye used during cavity preparation stains which tissue?

Denatured (infected, non-vital) dentin collagen that cannot remineralize (Correct answer)
All dentin exposed during preparation
Bacteria within dentinal tubules only
All demineralized enamel and dentin

Correct answer: Denatured (infected, non-vital) dentin collagen that cannot remineralize

Caries detector dye (1% acid red in propylene glycol) stains denatured, irreversibly infected dentin collagen that should be removed, while sparing affected but remineralizable inner dentin.

Question 77: Zinc oxide eugenol temporary cement should NOT be used under which type of restoration?

Metal crowns
Porcelain-fused-to-metal crowns
Composite resin restorations (Correct answer)
Amalgam restorations

Correct answer: Composite resin restorations

Eugenol inhibits the polymerization of composite resin, so ZOE cements are contraindicated as bases or temporaries under composite restorations.

Question 78: The periodontal ligament space visible on radiographs appears as which structure?

A radiopaque line surrounding the root
A radiolucent space between root and lamina dura (Correct answer)
A radiolucent halo around the apex only
A radiopaque band at the CEJ

Correct answer: A radiolucent space between root and lamina dura

The PDL space appears as a thin radiolucent line between the root surface (cementum) and the surrounding lamina dura (cortical bone of the socket).

Question 79: Which cell type is primarily responsible for dentinogenesis?

Ameloblasts
Odontoblasts (Correct answer)
Cementoblasts
Fibroblasts

Correct answer: Odontoblasts

Odontoblasts, derived from neural crest cells, are responsible for producing predentin which subsequently mineralizes to form dentin throughout life.

Question 80: During a maxillary sinus lift procedure, which vessel is most commonly encountered and must be avoided?

Posterior superior alveolar artery (Correct answer)
Facial artery
Greater palatine artery
Infraorbital artery

Correct answer: Posterior superior alveolar artery

The posterior superior alveolar artery courses through the lateral sinus wall and is the vessel most frequently encountered during sinus lift procedures.

Question 81: What is the name of the fibrous joint connecting the roots of a multi-rooted tooth to the alveolar bone?

Amphiarthrosis
Syndesmosis
Synarthrosis
Gomphosis (Correct answer)

Correct answer: Gomphosis

A gomphosis is a peg-in-socket fibrous joint formed by the periodontal ligament connecting the tooth root to the alveolar socket.

Question 82: The function of a surveyor in removable partial denture fabrication is to:

Evaluate the fit of the final metal framework on stone casts
Calculate the occlusal vertical dimension at rest
Measure the vertical dimension of the edentulous ridge
Determine the path of insertion and location of undercuts on abutment teeth (Correct answer)

Correct answer: Determine the path of insertion and location of undercuts on abutment teeth

A dental surveyor identifies the height of contour, undercut areas, and parallel surfaces on abutment teeth to design the path of insertion and RPD framework.

Question 83: According to Hamp's furcation classification, Class II involvement is defined as:

Vertical bone loss greater than 4 mm in the furcation
Horizontal loss encompassing the total width of the furcation area
Horizontal loss less than one-third the width of the tooth
Horizontal loss exceeding one-third the width but not encompassing the total width (Correct answer)

Correct answer: Horizontal loss exceeding one-third the width but not encompassing the total width

Hamp Class II means the probe penetrates horizontally more than one-third the tooth width but cannot pass completely through the furcation.

Question 84: The leeway space (E-space) refers to the size difference between which groups of teeth?

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

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 85: During a routine exam, a 55-year-old patient is noted to have a 1.5 cm asymptomatic bluish-purple swelling on the lower lip that blanches completely with pressure. This is most likely:

Hemangioma
Amalgam tattoo
Varix (Correct answer)
Mucocele

Correct answer: Varix

A varix (phlebectasia) is a dilated vein that blanches completely with pressure and appears as a bluish swelling, commonly found on the lower lip in older patients.

Question 86: Which tooth surface is most susceptible to root caries in the elderly population?

Proximal surface above the contact
Lingual surface
Buccal surface below the CEJ (Correct answer)
Occlusal surface

Correct answer: Buccal surface below the CEJ

Exposed root surfaces, especially buccal surfaces below the CEJ, are most susceptible to root caries due to gingival recession common in elderly patients.

Question 87: Post-operative sensitivity after posterior composite resin placement is most commonly attributed to:

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

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 88: Fordyce spots in the oral cavity represent:

Accessory parotid gland tissue
Ectopic sebaceous glands in the oral mucosa (Correct answer)
Lymphoid aggregates in the mucosa
Early leukoplakia

Correct answer: Ectopic sebaceous glands in the oral mucosa

Fordyce spots are ectopic sebaceous glands that appear as small yellowish spots on the buccal mucosa and lips, a normal variant requiring no treatment.

Question 89: Osteoplasty in periodontal surgery is best defined as:

Removal of alveolar bone that directly supports the tooth
Bone grafting of infrabony defects
Reshaping of non-supporting bone to achieve physiologic architecture (Correct answer)
Root resection in furcation-involved teeth

Correct answer: Reshaping of non-supporting bone to achieve physiologic architecture

Osteoplasty reshapes non-supporting (non-attachment) bone to improve bony architecture without sacrificing bone that directly supports the tooth.

Question 90: Fluoride varnish application in pediatric patients is recommended beginning at:

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

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 91: A patient on warfarin therapy requires a tooth extraction. The target INR range to proceed safely is generally:

1.5–2.0
Below 1.0
2.0–3.5 (Correct answer)
Above 4.0

Correct answer: 2.0–3.5

Current evidence supports proceeding with simple extractions when INR is within the therapeutic range of 2.0–3.5 without altering anticoagulation therapy.

Question 92: Which local anesthetic produces cutaneous vasoconstriction?

Prilocaine
Ropivacaine (Correct answer)
Procaine
None

Correct answer: Ropivacaine

Ropivacaine is a local anesthetic that possesses intrinsic vasoconstrictive properties, particularly at higher concentrations. This means it can cause blood vessels to constrict, which helps to prolong its duration of action and reduce systemic absorption. Unlike many other local anesthetics that often require an added vasoconstrictor like epinephrine, ropivacaine has this effect inherently.

Question 93: When you work in dental public health, you are asked to help plan a study to find out what benefits fluoridating the water supply has for the people in the area. Which of the following research designs, if any, is the most appropriate?

Cross-sectional study
Randomized controlled trial (Correct answer)
Case-control study
Cohort study

Correct answer: Randomized controlled trial

A Randomized Controlled Trial (RCT) is the most appropriate research design for evaluating the benefits of water fluoridation because it is considered the gold standard for establishing cause-and-effect relationships. By randomly assigning communities or individuals to receive fluoridated water or a control, RCTs minimize bias and confounding factors. This allows researchers to confidently attribute any observed health benefits, such as reduced caries rates, directly to the intervention.

Question 94: A patient's panoramic radiograph shows a well-defined, corticated radiolucency at the apex of a mandibular premolar with a history of prior endodontic treatment. The tooth tests non-vital. This is most consistent with:

Periapical cemento-osseous dysplasia
Periapical granuloma or cyst (Correct answer)
Periapical abscess
Traumatic bone cyst

Correct answer: Periapical granuloma or cyst

A well-defined corticated periapical radiolucency on a non-vital, treated tooth is most consistent with a periapical granuloma or cyst.

Question 95: Which periodontal fiber group is responsible for resisting intrusive forces on the tooth?

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

Correct answer: Oblique fibers

Oblique fibers, the most numerous PDL fibers, run from cementum in a coronal direction to alveolar bone and primarily resist intrusive (axial) forces.

Question 96: The zone of Weil (cell-free zone) in dental pulp is located:

In the central pulp core
Adjacent to the predentin
At the apex of the pulp chamber
Immediately below the odontoblast layer (Correct answer)

Correct answer: Immediately below the odontoblast layer

The cell-free zone of Weil lies just below (central to) the odontoblast layer and is relatively acellular, containing nerve plexus and capillaries.

Question 97: How many permanent teeth are in a full adult dentition, including third molars?

28
36
30
32 (Correct answer)

Correct answer: 32

A complete adult dentition consists of 32 permanent teeth: 8 incisors, 4 canines, 8 premolars, 8 first and second molars, and 4 third molars (wisdom teeth).

Question 98: What does the acronym 'BRONJ' refer to in dental practice?

Bisphosphonate-Related Osteonecrosis of the Jaw (Correct answer)
Bilateral Recurrent Oral Necrotic Junction
Buccal Recessive Oral Nerve Junction
Bone Resorption of Normal Jaw

Correct answer: Bisphosphonate-Related Osteonecrosis of the Jaw

BRONJ (now termed MRONJ—Medication-Related Osteonecrosis of the Jaw) is exposed necrotic bone in patients taking bisphosphonates or antiresorptive agents.

Question 99: A 6-year-old patient has a pulpally involved primary mandibular molar. The roots show no pathological resorption and the permanent successor is not at risk. Which treatment is indicated?

Pulpectomy with ZOE
Pulpotomy with formocresol or MTA (Correct answer)
Direct pulp cap
Extraction

Correct answer: Pulpotomy with formocresol or MTA

Pulpotomy is the treatment of choice for primary molars with carious pulp exposure when the radicular pulp is healthy and roots are intact.

Question 100: Rapid palatal expansion (RPE) is used to correct:

Class II malocclusion by advancing the mandible
Mandibular prognathism
Bilateral posterior crossbite due to maxillary arch constriction (Correct answer)
Deep overbite with supraocclusion of incisors

Correct answer: Bilateral posterior crossbite due to maxillary arch constriction

RPE applies transverse forces to open the midpalatal suture, widening the maxillary arch to correct bilateral posterior crossbites caused by maxillary skeletal constriction.

Question 101: Crown lengthening surgery is most commonly indicated when:

A patient has drug-induced gingival overgrowth unrelated to restoration
A tooth has Class II furcation involvement
There is insufficient supragingival tooth structure for an adequate restoration (Correct answer)
A tooth requires orthodontic tooth movement

Correct answer: There is insufficient supragingival tooth structure for an adequate restoration

Crown lengthening removes gingival and/or osseous tissue to expose adequate tooth structure, ensuring restorative margins respect biologic width and provide sufficient ferrule.

Question 102: The landmark 'pterygomandibular raphe' serves as a guide for which injection technique?

Posterior superior alveolar block
Inferior alveolar nerve block (Correct answer)
Infraorbital block
Greater palatine block

Correct answer: Inferior alveolar nerve block

The pterygomandibular raphe is the buccal landmark lateral to which the needle is directed for the inferior alveolar nerve block.

Question 103: 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 II periodontitis (Correct answer)
Gingivitis
Stage I periodontitis
Stage III periodontitis

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 104: When is it appropriate to use a rubber dam during endodontic treatment?

Only when the patient requests it
For all routine root canal procedures to prevent contamination (Correct answer)
Only for posterior teeth
Only when using rotary files

Correct answer: For all routine root canal procedures to prevent contamination

Rubber dam isolation is mandatory for all root canal procedures to prevent microbial contamination of the canal system and protect the patient from aspiration.

Question 105: The primary treatment for early childhood caries (nursing bottle caries) is:

Elimination of the cariogenic feeding habit, diet counseling, and restorative treatment of affected teeth (Correct answer)
Immediate full-mouth extraction under general anesthesia
Prescription fluoride drops alone
Watchful waiting until all primary teeth have erupted

Correct answer: Elimination of the cariogenic feeding habit, diet counseling, and restorative treatment of affected teeth

ECC treatment requires stopping the cariogenic behavior (nocturnal bottle feeding with fermentable carbohydrates), parent education, diet modification, and prompt restorative/preventive dental care.

Question 106: In complete denture fabrication, the Gothic arch (needle point) tracing is used to determine:

The centric relation position of the mandible (Correct answer)
The vertical dimension of occlusion
The curve of Spee for posterior teeth placement
The horizontal overlap (overjet) of the anterior teeth

Correct answer: The centric relation position of the mandible

The Gothic arch (arrowhead) tracing records centric relation — the apex of the arrow points to the most retruded, unstrained condylar position.

Question 107: 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
Lips
Tongue (Correct answer)
Soft palate

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 108: Which virus is most strongly associated with hairy leukoplakia of the lateral tongue in immunocompromised patients?

Human papillomavirus (HPV)
Herpes simplex virus type 1 (HSV-1)
Cytomegalovirus (CMV)
Epstein-Barr virus (EBV) (Correct answer)

Correct answer: Epstein-Barr virus (EBV)

Hairy leukoplakia is caused by EBV replication in superficial epithelial cells and is a marker of significant immune suppression, especially in HIV-positive patients.

Question 109: Which class of antibiotics works by inhibiting bacterial cell wall synthesis by binding penicillin-binding proteins?

Beta-lactams (Correct answer)
Aminoglycosides
Tetracyclines
Macrolides

Correct answer: Beta-lactams

Beta-lactam antibiotics (penicillins, cephalosporins) inhibit transpeptidases (penicillin-binding proteins) needed for peptidoglycan cross-linking in the bacterial cell wall.

Question 110: What is the accepted normal sulcus probing depth in a clinically healthy periodontium?

4–5 mm
6–7 mm
0–1 mm
1–3 mm (Correct answer)

Correct answer: 1–3 mm

A healthy gingival sulcus measures 1–3 mm on probing; depths ≥4 mm indicate pathological pocket formation.

Question 111: The primary reason for placing stainless steel crowns (SSC) on primary molars with large multi-surface caries is:

SSCs prevent adjacent teeth from drifting
SSCs stimulate eruption of the successor premolar
Aesthetic preference over composite restorations
Full coronal coverage provides superior longevity and fracture resistance compared to multi-surface amalgam (Correct answer)

Correct answer: Full coronal coverage provides superior longevity and fracture resistance compared to multi-surface amalgam

Stainless steel crowns provide complete cuspal coverage that resists fracture from masticatory forces, making them significantly more durable than multi-surface direct restorations for primary molars with extensive decay.

Question 112: Which type of impression material is dimensionally most stable over time and most accurate for implant-level impressions?

Zinc oxide eugenol impression paste
Alginate (irreversible hydrocolloid)
Polysulfide
Polyether (Correct answer)

Correct answer: Polyether

Polyether impression materials have excellent dimensional stability, low water sorption/solubility, and high stiffness, making them the gold standard for implant-level and precision fixed prosthodontic impressions.

Question 113: A patient develops trismus after an inferior alveolar nerve block. The most likely cause is:

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

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 114: Bisphosphonate-related osteonecrosis of the jaw (BRONJ/MRONJ) most commonly occurs after which dental procedure?

Tooth extraction (dentoalveolar surgery) (Correct answer)
Composite resin restoration
Orthodontic bracket placement
Routine scaling and root planing

Correct answer: Tooth extraction (dentoalveolar surgery)

Tooth extraction and other dentoalveolar surgeries that disrupt the oral mucosa and bone are the most common triggers for MRONJ in patients on bisphosphonate therapy.

Question 115: The periodontal 'red complex,' identified by Socransky et al., consists of which triad of organisms?

Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola (Correct answer)
Streptococcus mutans, Lactobacillus acidophilus, Actinomyces viscosus
Bacteroides forsythus, Eikenella corrodens, Campylobacter rectus
Aggregatibacter actinomycetemcomitans, Prevotella intermedia, Fusobacterium nucleatum

Correct answer: Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola

The red complex (Socransky et al., 1998) comprises P. gingivalis, T. forsythia, and T. denticola — the most virulent bacterial cluster strongly correlated with deep pockets and bleeding on probing.

Question 116: Peri-implantitis is best described as:

An inflammatory condition causing progressive bone loss around a dental implant (Correct answer)
Inflammation confined to peri-implant soft tissues only
Bone loss around an implant due solely to occlusal overload
A normal remodeling response after implant placement

Correct answer: An inflammatory condition causing progressive bone loss around a dental implant

Peri-implantitis involves plaque-induced inflammatory changes in the peri-implant mucosa accompanied by progressive loss of supporting bone beyond initial remodeling.

Question 117: Which tooth movement produces the greatest amount of root resorption during orthodontic treatment?

Intrusion (Correct answer)
Tipping
Rotation
Extrusion

Correct answer: Intrusion

Intrusive tooth movement produces the greatest root resorption because it concentrates force at the root apex.

Question 118: When fabricating a removable partial denture (RPD), which component prevents unwanted movement of the RPD away from the tissue?

Rest
Retentive clasp arm (Correct answer)
Reciprocal clasp
Minor connector

Correct answer: Retentive clasp arm

The retentive clasp arm engages an undercut on the abutment tooth to prevent dislodgment of the RPD away from the tissues.

Question 119: Which type of tooth movement requires the most force in orthodontics?

Translation (bodily movement) (Correct answer)
Torque (root movement)
Tipping
Intrusion

Correct answer: Translation (bodily movement)

Bodily translation requires the entire tooth to move with the root and crown moving equally, demanding greater PDL stimulation area and more controlled force than simple tipping.

Question 120: The occlusal scheme most commonly recommended for complete dentures is:

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

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 121: Which root cementum type contains entrapped cementoblasts within its matrix?

Cellular intrinsic fiber cementum (Correct answer)
Acellular afibrillar cementum
Acellular extrinsic fiber cementum
Cellular mixed stratified cementum

Correct answer: Cellular intrinsic fiber cementum

Cellular intrinsic fiber cementum contains cementocytes trapped in lacunae, similar to how osteocytes are trapped in bone.

Question 122: Which type of dentin is produced throughout the life of the tooth in response to normal physiologic stimuli?

Secondary dentin (Correct answer)
Tertiary dentin
Primary dentin
Sclerotic dentin

Correct answer: Secondary dentin

Secondary dentin is deposited by odontoblasts after root formation is complete and continues slowly throughout the tooth's functional life.

Question 123: When replacing a missing mandibular first molar with a three-unit fixed bridge, the abutment teeth most commonly used are:

Second premolar and first premolar
Second premolar and second molar (Correct answer)
First premolar and third molar
Canine and second molar

Correct answer: Second premolar and second molar

The second premolar and second molar serve as the natural abutments flanking the missing first molar space, providing the shortest span and most predictable bridge design.

Question 124: In dental implant terminology, osseointegration is defined as:

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

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 125: Which enzyme in saliva initiates carbohydrate digestion in the oral cavity?

Carbonic anhydrase
Salivary amylase (ptyalin) (Correct answer)
Lysozyme
Lingual lipase

Correct answer: Salivary amylase (ptyalin)

Salivary amylase (ptyalin) begins starch digestion in the mouth by cleaving alpha-1,4 glycosidic bonds in polysaccharides.

Question 126: The Ante's Law in fixed partial denture design states that:

Each bridge unit requires 1 mm occlusal reduction for porcelain
Abutment teeth must have a crown-to-root ratio of at least 1:1.5
The combined root surface area of abutment teeth must equal or exceed that of the teeth being replaced (Correct answer)
The pontic span should not exceed the length of the abutment teeth

Correct answer: The combined root surface area of abutment teeth must equal or exceed that of the teeth being replaced

Ante's Law holds that the combined periodontal ligament area (root surface area) of abutment teeth should be equal to or greater than that of the teeth being replaced by the pontic(s).

Question 127: Which instrument is specifically designed to remove supragingival and subgingival calculus by using a pull stroke on root surfaces?

Periodontal probe
Sickle scaler
Explorer
Curette (Correct answer)

Correct answer: Curette

Curettes (such as Gracey curettes) have a rounded toe and back, allowing safe subgingival access on root surfaces using a pull stroke to remove calculus and root-surface deposits.

Question 128: What is the approximate pH at which hydroxyapatite in enamel begins to dissolve (critical pH)?

4.5
6.2
6.8
5.5 (Correct answer)

Correct answer: 5.5

The critical pH for enamel dissolution is approximately 5.5; below this level, the oral environment becomes undersaturated with respect to hydroxyapatite and demineralization occurs.

Question 129: A patient has a Kennedy Class II removable partial denture. Which design feature must be incorporated to prevent rotation of the prosthesis during function?

Indirect retainers (Correct answer)
Major connector
Reciprocal clasp
Tooth-colored clasps

Correct answer: Indirect retainers

Indirect retainers placed anterior to the fulcrum line prevent the distal extension base from tipping or rotating away from the tissue when occlusal force is applied.

Question 130: Which dental material contains bisphenol A-glycidyl methacrylate (Bis-GMA) as its primary resin matrix?

Glass ionomer cement
Zinc oxide eugenol cement
Zinc phosphate cement
Composite resin (Correct answer)

Correct answer: Composite resin

Composite resin restorative materials are based on Bis-GMA (bisphenol A-glycidyl methacrylate) monomer cross-linked with TEGDMA, providing tooth-colored esthetic restorations.

Question 131: A patient with poorly controlled type 2 diabetes presents for a full-mouth debridement. Which laboratory value is most useful for assessing long-term glycemic control?

Serum insulin level
Random blood glucose
Fasting blood glucose
HbA1c (glycated hemoglobin) (Correct answer)

Correct answer: HbA1c (glycated hemoglobin)

HbA1c reflects average blood glucose over the preceding 2–3 months and is the best indicator of long-term glycemic control.

Question 132: Which local anesthetic has the longest duration of action for dental pulp anesthesia?

Mepivacaine
Prilocaine
Lidocaine
Bupivacaine (Correct answer)

Correct answer: Bupivacaine

Bupivacaine (Marcaine) provides the longest duration of pulpal anesthesia (up to 5–7 hours) due to its high lipid solubility and protein binding.

Question 133: The pKa of lidocaine is approximately 7.9. In an infected (acidic) tissue environment, anesthesia is difficult because:

More of the drug is in the ionized (charged) form, which cannot penetrate the nerve membrane (Correct answer)
The pH rise increases vasoconstriction and limits drug delivery
Infection destroys the drug before it can act
Acidic tissue accelerates myelination of nerve fibers

Correct answer: More of the drug is in the ionized (charged) form, which cannot penetrate the nerve membrane

At lower pH (acidic infection), the equilibrium shifts toward the ionized (protonated, BH+) form of the local anesthetic, which cannot penetrate lipid nerve membranes to reach the sodium channel.

Question 134: What is the term for the bony projection on the lingual surface of the mandible where the mylohyoid muscle attaches?

Genial tubercle
Mental spine
Oblique ridge
Mylohyoid ridge (Correct answer)

Correct answer: Mylohyoid ridge

The mylohyoid ridge (internal oblique ridge) runs diagonally on the lingual surface of the mandible and serves as the attachment for the mylohyoid muscle.

Question 135: The Modified Widman Flap procedure was primarily designed to:

Create new attachment via regeneration
Eliminate pockets through tissue resection
Provide access for root debridement while preserving maximum tissue (Correct answer)
Provide access for extensive osseous recontouring

Correct answer: Provide access for root debridement while preserving maximum tissue

The Modified Widman Flap (Ramfjord and Nissle, 1974) prioritizes access for thorough root debridement with minimal surgical trauma and tissue sacrifice.

Question 136: What is the primary buffer system in saliva that resists pH changes caused by bacterial acids?

Bicarbonate buffer system (Correct answer)
Protein buffer system
Phosphate buffer system
Urea buffer system

Correct answer: Bicarbonate buffer system

The bicarbonate buffer system is the dominant buffering mechanism in stimulated saliva, neutralizing acids produced by cariogenic bacteria to protect enamel.

Question 137: The inferior alveolar nerve block anesthetizes which teeth and structures?

Ipsilateral mandibular teeth, buccal gingiva of anterior teeth, lower lip, and chin
All mandibular teeth bilaterally
Ipsilateral mandibular teeth from the third molar to the midline, plus lingual gingiva and tongue (Correct answer)
All maxillary teeth ipsilaterally

Correct answer: Ipsilateral mandibular teeth from the third molar to the midline, plus lingual gingiva and tongue

The IANB anesthetizes the ipsilateral mandibular teeth (to the midline), the lingual gingiva and anterior two-thirds of the tongue (via the lingual nerve), and the lower lip and chin (via the mental nerve).

Question 138: The maximum recommended dose of lidocaine with epinephrine (1:100,000) for a healthy 70 kg adult dental patient is approximately:

100 mg (≈2.7 carpules)
200 mg (≈5.5 carpules)
700 mg (≈19.4 carpules)
500 mg (≈13.9 carpules) (Correct answer)

Correct answer: 500 mg (≈13.9 carpules)

The MRD of lidocaine with vasoconstrictor is 7 mg/kg, giving approximately 500 mg (about 13–14 carpules of 1.8 mL 2% lidocaine) for a 70 kg patient.

Question 139: Cocaine is unique among local anesthetics used clinically because it:

Is used topically due to its intrinsic vasoconstrictive and local anesthetic properties (Correct answer)
Has no toxicity potential at clinical doses
Is the standard of care for inferior alveolar nerve blocks
Is the only ester-type local anesthetic with vasoconstrictor properties

Correct answer: Is used topically due to its intrinsic vasoconstrictive and local anesthetic properties

Cocaine is unique in both blocking sodium channels (local anesthesia) and inhibiting norepinephrine reuptake (vasoconstriction), making it useful topically in nasal/ENT surgery but not injected dental anesthesia.

Question 140: The perikymata visible on the crown surface of a tooth correspond to which histologic structure?

Enamel spindles
Striae of Retzius (Correct answer)
Enamel tufts
Hunter-Schreger bands

Correct answer: Striae of Retzius

Perikymata are the external surface manifestations of the striae of Retzius, representing incremental growth lines in enamel.

Question 141: Erythema multiforme affecting the oral mucosa characteristically presents as:

Punched-out ulcers on attached gingiva
Target or iris lesions with hemorrhagic crusting of the lips (Correct answer)
Raised white plaques on the buccal mucosa
Vesicles along the distribution of the trigeminal nerve

Correct answer: Target or iris lesions with hemorrhagic crusting of the lips

Oral erythema multiforme classically shows hemorrhagic crusting and ulceration of the lips with target lesions on the skin, often triggered by HSV.

Question 142: Which nerve must be anesthetized to achieve pulpal anesthesia of the maxillary molars during routine dental procedures?

Nasopalatine nerve
Inferior alveolar nerve
Posterior superior alveolar and middle superior alveolar nerves (Correct answer)
Posterior superior alveolar nerve only

Correct answer: Posterior superior alveolar and middle superior alveolar nerves

Maxillary molar pulpal anesthesia requires the posterior superior alveolar nerve (for roots) and often the middle superior alveolar nerve (for mesiobuccal root and surrounding tissue).

Question 143: Tetracyclines are contraindicated in children under 8 years old primarily because they:

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

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 144: The primary function of a space maintainer after premature loss of a primary second molar is to:

Guide the permanent canine into proper position
Maintain the vertical dimension of occlusion
Prevent mesial drift of the permanent first molar into the extraction space (Correct answer)
Stimulate eruption of the underlying premolar

Correct answer: Prevent mesial drift of the permanent first molar into the extraction space

After loss of a primary second molar, the permanent first molar tends to drift mesially, reducing arch length needed for the permanent second premolar; a space maintainer prevents this migration.

Question 145: Which suture material is preferred for intraoral wounds because it dissolves without removal?

Prolene
Polyglycolic acid (Dexon) (Correct answer)
Nylon
Silk

Correct answer: Polyglycolic acid (Dexon)

Resorbable sutures like polyglycolic acid (Dexon) or polyglactin (Vicryl) are preferred intraorally because patients do not need to return for removal.

Question 146: A patient presents with a palatal torus that is interfering with denture fabrication. The surgeon plans a torus removal. Which nerve block is most important for anesthesia of the palatal mucosa overlying the torus?

Nasopalatine nerve block
Greater palatine nerve block
Both greater palatine and nasopalatine nerve blocks (Correct answer)
Inferior alveolar nerve block

Correct answer: Both greater palatine and nasopalatine nerve blocks

The palatal mucosa is innervated by both the greater palatine nerve (posterior) and the nasopalatine nerve (anterior), so both blocks are required for complete anesthesia.

Question 147: Which feature most distinguishes odontogenic keratocyst from other jaw cysts histologically?

Extensive inflammatory infiltrate with Rushton bodies
Thick fibrous wall with cholesterol clefts
Mucous cells within the cyst lining
Thin corrugated parakeratinized epithelium with a basal cell layer showing palisading (Correct answer)

Correct answer: Thin corrugated parakeratinized epithelium with a basal cell layer showing palisading

OKC has a distinctive thin, uniform parakeratinized stratified squamous epithelium with a prominent palisaded cuboidal-to-columnar basal cell layer and corrugated surface.

Question 148: Enamel hypoplasia differs from fluorosis in that it:

Is caused exclusively by vitamin D deficiency
Affects only primary teeth, never permanent teeth
Always appears as white spot lesions, identical to fluorosis
Represents a quantitative defect in enamel thickness, while fluorosis is a qualitative (hypomineralization) defect (Correct answer)

Correct answer: Represents a quantitative defect in enamel thickness, while fluorosis is a qualitative (hypomineralization) defect

Hypoplasia is a quantitative defect (reduced enamel formation/thickness) from any systemic or local insult during matrix formation, while fluorosis is a qualitative hypomineralization from excess fluoride during maturation.

Question 149: Hertwig's epithelial root sheath is derived from which two epithelial layers?

Stratum intermedium and stellate reticulum
Inner enamel epithelium and outer enamel epithelium (Correct answer)
Outer enamel epithelium and stellate reticulum
Inner enamel epithelium and stratum intermedium

Correct answer: Inner enamel epithelium and outer enamel epithelium

Hertwig's epithelial root sheath is a double layer formed by the fusion of the inner and outer enamel epithelium at the cervical loop after crown formation.

Question 150: 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)
Upper and lower second premolars
Maxillary and mandibular canines only

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 151: Silver diamine fluoride (SDF) arrests dental caries primarily by:

Rehydrating demineralized enamel crystals
Stimulating secondary dentin formation
Fluoride incorporating into hydroxyapatite while silver ions kill cariogenic bacteria (Correct answer)
Mechanically sealing dentinal tubules with silver precipitate

Correct answer: Fluoride incorporating into hydroxyapatite while silver ions kill cariogenic bacteria

SDF arrests caries through dual action: fluoride ion remineralizes and hardens enamel/dentin while silver ions (Ag+) provide broad-spectrum antimicrobial activity against cariogenic bacteria.

Question 152: A patient presents with a 'moth-eaten' pattern of bone destruction on radiograph. This appearance is most characteristic of which condition?

Osteomyelitis (Correct answer)
Osteosarcoma
Chronic periapical abscess
Central giant cell granuloma

Correct answer: Osteomyelitis

Osteomyelitis classically produces a 'moth-eaten' pattern of bone destruction due to diffuse infiltration by the infectious process.

Question 153: Which base or liner could hinder a resin composite restoration from polymerizing?

Calcium hydroxide
Glass ionomer
Copolymer
Zinc oxide eugenol (Correct answer)

Correct answer: Zinc oxide eugenol

Zinc oxide eugenol (ZOE) contains eugenol, which is known to inhibit the polymerization of resin-based materials. Eugenol can interfere with the free radical polymerization process of composite resins, leading to incomplete curing, reduced bond strength, and compromised restoration integrity. Therefore, ZOE should be avoided as a base or liner under composite restorations.

Question 154: Which index measures the severity of periodontal disease by assessing loss of attachment and bone level?

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

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

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

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 156: The term 'torus mandibularis' refers to:

An osteoma of the mandibular condyle
An exostosis on the hard palate midline
A benign bony exostosis on the lingual aspect of the mandible in the premolar region (Correct answer)
A reactive bone growth on the buccal alveolar ridge

Correct answer: A benign bony exostosis on the lingual aspect of the mandible in the premolar region

Torus mandibularis is a benign developmental exostosis located on the lingual surface of the mandible, typically in the premolar region, and is bilateral in most cases.

Question 157: In Class V composite resin restorations, which factor most contributes to marginal failure at the gingival margin?

Poor bonding to cementum/dentin and flexural stress from toothbrushing (abfraction) (Correct answer)
Thermal expansion mismatch between composite and enamel
Insufficient light curing through intact enamel
Excessive fluoride incorporation weakening the adhesive interface

Correct answer: Poor bonding to cementum/dentin and flexural stress from toothbrushing (abfraction)

Class V cervical restorations fail primarily due to inadequate dentin bonding (cementum has no enamel rods to etch) combined with flexural stress from occlusal loads (abfraction) at the cervical fulcrum.

Question 158: The 'biologic width' of the periodontium comprises which two structures?

Junctional epithelium and supracrestal connective tissue attachment (Correct answer)
Alveolar bone and periodontal ligament
Free and attached gingiva
Sulcus depth and free gingiva

Correct answer: Junctional epithelium and supracrestal connective tissue attachment

Biologic width (~2 mm) consists of the junctional epithelium (~1 mm) and the supracrestal connective tissue attachment (~1 mm); violations cause chronic inflammation.

Question 159: Epinephrine in local anesthetic cartridges acts by:

Causing local vasoconstriction to slow systemic absorption and prolong anesthesia (Correct answer)
Inhibiting prostaglandin synthesis at the injection site
Directly blocking sodium channels to enhance anesthesia depth
Raising the pH of the solution to increase un-ionized free base form

Correct answer: Causing local vasoconstriction to slow systemic absorption and prolong anesthesia

Epinephrine binds alpha-1 adrenoceptors causing vasoconstriction, reducing vascular absorption of the local anesthetic and thereby prolonging its duration and reducing toxicity risk.

Question 160: Which type of bone graft uses bone harvested from the same individual receiving the graft?

Autograft (Correct answer)
Xenograft
Allograft
Alloplast

Correct answer: Autograft

An autograft (autogenous bone graft) uses bone harvested from the patient's own body (e.g., chin, ramus, iliac crest) and is considered the gold standard for bone regeneration.

Question 161: Which drug interaction requires dose reduction or avoidance when prescribing erythromycin or clarithromycin to a dental patient taking simvastatin?

Inhibition of CYP3A4 increases simvastatin levels, raising risk of myopathy/rhabdomyolysis (Correct answer)
Increased simvastatin metabolism reducing cholesterol control
Erythromycin displaces simvastatin from plasma protein binding causing toxicity
Reduced antibiotic absorption in the presence of statins

Correct answer: Inhibition of CYP3A4 increases simvastatin levels, raising risk of myopathy/rhabdomyolysis

Erythromycin and clarithromycin inhibit CYP3A4, reducing first-pass metabolism of simvastatin and dramatically increasing its plasma levels, which can cause severe myopathy or rhabdomyolysis.

Question 162: Which cement is most appropriate for final cementation of a zirconia crown?

Zinc phosphate
Resin cement (Correct answer)
Polycarboxylate
Glass ionomer

Correct answer: Resin cement

Resin cement provides optimal bond strength to zirconia, especially when used with appropriate surface treatment and primers.

Question 163: Nitrous oxide (N₂O) produces analgesia and sedation primarily by:

Sodium channel blockade in the CNS
GABA receptor potentiation and NMDA receptor antagonism (Correct answer)
Dopamine reuptake inhibition
Direct opioid receptor agonism

Correct answer: GABA receptor potentiation and NMDA receptor antagonism

N₂O exerts its effects via potentiation of GABA-A inhibitory neurotransmission and antagonism of NMDA (glutamate) receptors, reducing pain transmission and producing anxiolysis.

Question 164: Which nerve provides sensory innervation to the mandibular anterior teeth?

Incisive nerve (Correct answer)
Lingual nerve
Inferior alveolar nerve
Mental nerve

Correct answer: Incisive nerve

The incisive nerve, a terminal branch of the inferior alveolar nerve, innervates the mandibular anterior teeth and premolars.

Question 165: The recommended interval for supportive periodontal therapy (maintenance) in most treated periodontitis patients is:

Every 6 months
Every 3–4 months (Correct answer)
Every 12 months
Every 1–2 months

Correct answer: Every 3–4 months

A 3–4 month maintenance interval is standard because pathogenic subgingival bacteria recolonize treated pockets within this timeframe.

Question 166: Which primary (deciduous) teeth are the last to erupt in the oral cavity?

Maxillary central incisors
Maxillary second molars (Correct answer)
Mandibular lateral incisors
Mandibular canines

Correct answer: Maxillary second molars

The maxillary second primary molars are typically the last deciduous teeth to erupt, around 24–33 months of age, completing the primary dentition of 20 teeth.

Question 167: A patient taking warfarin requires tooth extraction. Which INR threshold is generally accepted as safe for routine dental extractions without altering anticoagulation therapy?

INR ≥ 4.0
INR < 1.5
INR ≤ 3.5 (Correct answer)
INR < 2.0

Correct answer: INR ≤ 3.5

Current evidence supports performing routine dental extractions when the INR is ≤ 3.5 without altering warfarin, using local hemostatic measures rather than risking thromboembolic events from stopping anticoagulation.

Question 168: Which drug classification requires the use of prophylactic antibiotics before invasive dental procedures according to the American Heart Association guidelines?

Patients with pacemakers
Patients with coronary artery disease on aspirin
Patients with prosthetic heart valves (Correct answer)
Patients with controlled hypertension

Correct answer: Patients with prosthetic heart valves

The AHA recommends antibiotic prophylaxis before dental procedures for patients with prosthetic heart valves due to high risk of adverse outcomes from infective endocarditis.

Question 169: Which cell is responsible for the formation of the dental lamina?

Ectomesenchymal cells
Neural crest cells
Oral epithelial cells (Correct answer)
Endodermal cells

Correct answer: Oral epithelial cells

The dental lamina arises from proliferation of the oral (ectoderm-derived) epithelium as it invaginates into the underlying ectomesenchyme.

Question 170: A patient with poorly controlled type 2 diabetes is more susceptible to periodontitis primarily because of:

Impaired neutrophil function and advanced glycation end-products (Correct answer)
Xerostomia reducing plaque buffering
Increased calculus deposition
Increased salivary glucose feeding bacteria

Correct answer: Impaired neutrophil function and advanced glycation end-products

Hyperglycemia impairs neutrophil chemotaxis and phagocytosis and promotes formation of AGEs, which upregulate inflammatory cytokines and damage periodontal tissues.

Question 171: A removable partial denture major connector for a mandibular arch should be located:

Directly over the ridge crest
At least 3–4 mm from the gingival margins (Correct answer)
On the cingula of anterior teeth
On the labial surface of anterior teeth

Correct answer: At least 3–4 mm from the gingival margins

Mandibular major connectors must be placed at least 3–4 mm from the gingival margins to avoid impingement on gingival tissues.

Question 172: What is the color code for a medium-level emergency patient?

Yellow (Correct answer)
Black
None
Red

Correct answer: Yellow

In emergency triage systems, color codes are used to quickly classify patients based on the severity of their condition and the urgency of treatment. Yellow typically designates patients with a medium-level emergency, indicating their condition is serious but not immediately life-threatening, allowing for a short wait for treatment. Red is for immediate life-threatening conditions, and black for deceased or expectant deceased.

Question 173: Geographic tongue (benign migratory glossitis) is characterized by:

Hyperplasia of filiform papillae causing hairy tongue appearance
Painful vesicular eruption limited to the dorsal tongue
Permanent depapillation with no healing capacity
Migratory areas of erythema surrounded by a white keratotic border that change over days (Correct answer)

Correct answer: Migratory areas of erythema surrounded by a white keratotic border that change over days

Geographic tongue shows irregular areas of desquamation of filiform papillae (red zones) with a white serpiginous border that shifts location over days to weeks.

Question 174: In orthodontic treatment, a headgear appliance with a cervical-pull (low-pull) force direction applies force that:

Protrudes the maxillary molars mesially
Distalizes and extrudes the maxillary molars, restraining forward maxillary growth (Correct answer)
Intrudes and retracts the maxillary molars vertically
Intrudes the maxillary incisors

Correct answer: Distalizes and extrudes the maxillary molars, restraining forward maxillary growth

A low-pull cervical headgear applies a downward and backward force on the maxillary molars, extruding and distalizing them while restraining forward maxillary skeletal growth.

Question 175: The term 'leukoplakia' in oral pathology refers to:

A specific diagnosis of dysplastic epithelium
Any white patch of the oral mucosa that cannot be wiped off and cannot be diagnosed as any other disease (Correct answer)
White lesions caused exclusively by candidal infection
Hyperkeratosis with no malignant potential

Correct answer: Any white patch of the oral mucosa that cannot be wiped off and cannot be diagnosed as any other disease

Leukoplakia is a clinical term for a white patch that cannot be rubbed off and cannot be characterized as any other definable disease, requiring biopsy for definitive diagnosis.

Question 176: Which of the following is the MOST important factor in determining the long-term success of an implant?

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

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 177: NSAIDs reduce dental pain primarily by inhibiting which enzyme?

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

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 178: What is the primary purpose of the gingival fiber group called the transseptal fibers?

Connect adjacent teeth through the interproximal space (Correct answer)
Support the free gingival margin
Attach the gingiva to the alveolar crest
Resist occlusal forces

Correct answer: Connect adjacent teeth through the interproximal space

Transseptal fibers extend interproximally between adjacent teeth, connecting them through the interdental space above the alveolar bone.

Question 179: Scaling and root planing (SRP) is considered the gold standard of which type of periodontal therapy?

Non-surgical therapy (Correct answer)
Maintenance therapy
Surgical therapy
Regenerative therapy

Correct answer: Non-surgical therapy

SRP is the cornerstone of non-surgical periodontal therapy, mechanically removing calculus and biofilm from root surfaces to reduce pathogenic bacterial load.

Question 180: Which tooth movement type results in the highest rate of root resorption during orthodontic treatment?

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

Correct answer: Intrusion

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

Question 181: Ranula is a mucous retention/extravasation lesion arising from which gland?

Parotid gland
Minor salivary glands of the palate
Sublingual gland (Correct answer)
Submandibular gland

Correct answer: Sublingual gland

Ranula is a mucocele of the floor of the mouth arising from the sublingual gland or its ducts, and can extend into the neck as a plunging ranula.

Question 182: Muscle that has been penetrated in IANB?

Temporalis
Buccinator (Correct answer)
Medial pterygoid
All

Correct answer: Buccinator

During an Inferior Alveolar Nerve Block (IANB), the needle typically penetrates the buccinator muscle as it advances towards the pterygomandibular space. The buccinator muscle forms the bulk of the cheek and is superficial to the target nerves and vessels in this region. While other muscles are nearby, the buccinator is the one directly pierced by the needle.

Question 183: A patient presents with a buccal space abscess originating from a maxillary first molar. Which structure must the infection perforate to reach the buccal space?

Buccinator muscle (Correct answer)
Mylohyoid muscle
Medial pterygoid muscle
Masseter muscle

Correct answer: Buccinator muscle

The buccal space lies superficial to the buccinator muscle, so infection from the maxillary molar must penetrate the buccinator to reach this space.

Question 184: Opioid analgesics produce analgesia by acting primarily on which receptors?

NMDA receptors in the dorsal horn
GABA-B receptors in the thalamus
Substance P receptors (NK1) in the trigeminal nucleus
Mu (μ), delta (δ), and kappa (κ) opioid receptors (Correct answer)

Correct answer: Mu (μ), delta (δ), and kappa (κ) opioid receptors

Opioids bind mu, delta, and kappa receptors (GPCRs) in the CNS and peripheral nociceptors, inhibiting adenylyl cyclase and reducing neuronal excitability and pain transmission.

Question 185: Which carious lesion classification system is based on location and morphology rather than severity?

Mount and Hume system
Pitts classification
G.V. Black's cavity classification (Correct answer)
ICDAS

Correct answer: G.V. Black's cavity classification

G.V. Black's cavity classification (Classes I–VI) categorizes cavities by anatomical location and surface involved, forming the basis for cavity preparation design.

Question 186: Which teeth are most commonly affected by pericoronitis?

Mandibular third molars (Correct answer)
Mandibular second premolars
Maxillary first molars
Maxillary canines

Correct answer: Mandibular third molars

Pericoronitis most commonly affects partially erupted mandibular third molars (wisdom teeth), where the overlying gingival flap traps bacteria.

Question 187: Acute necrotizing ulcerative gingivitis (ANUG) is characterized by all of the following EXCEPT:

Deep periodontal pocket formation (Correct answer)
Pseudomembrane formation on gingival surfaces
Characteristic fetid breath odor
Painful punched-out ulcers of interdental papillae

Correct answer: Deep periodontal pocket formation

ANUG typically does NOT produce pockets because tissue destruction occurs coronally without apical migration of the junctional epithelium.

Question 188: Squamous cell carcinoma of the oral cavity has the highest incidence in which site?

Dorsal tongue
Lateral and ventral tongue/floor of mouth (Correct answer)
Hard palate
Buccal mucosa

Correct answer: Lateral and ventral tongue/floor of mouth

The lateral/ventral tongue and floor of mouth together represent the most common sites for oral squamous cell carcinoma in the United States.

Question 189: Which articulator type is required to accurately reproduce eccentric jaw movements using individual patient records?

Semi-adjustable articulator
Fully adjustable articulator (Correct answer)
Non-arcon simple hinge articulator
Average value articulator

Correct answer: Fully adjustable articulator

A fully adjustable (arcon) articulator accepts individual pantographic or stereographic records and replicates the exact condylar guidance and Bennett angle of a specific patient.

Question 190: Which condition is characterized by bilateral enlargement of the parotid glands and keratoconjunctivitis sicca (dry eyes)?

Mikulicz disease
Sjögren syndrome (Correct answer)
Sarcoidosis
Mumps

Correct answer: Sjögren syndrome

Sjögren syndrome is an autoimmune exocrinopathy featuring bilateral parotid enlargement, xerostomia, and keratoconjunctivitis sicca due to lymphocytic infiltration of exocrine glands.

Question 191: Which anatomical landmark on the hard palate is used as a reference point in prosthodontic impressions?

Pterygomaxillary notch
Fovea palatinae (Correct answer)
Incisive papilla
Hamular notch

Correct answer: Fovea palatinae

The fovea palatinae are two small pits at the junction of the hard and soft palate and serve as a reliable landmark for establishing the posterior border of a complete maxillary denture.

Question 192: Which suturing technique is best for closing a wound with primary intention in a narrow interdental space after periodontal flap surgery?

Mattress suture
Interrupted suture
Figure-eight suture
Continuous sling suture (Correct answer)

Correct answer: Continuous sling suture

A continuous sling suture anchors the flap around the teeth, providing excellent approximation in the interdental areas after periodontal surgery.

Question 193: Which Angle's classification describes a malocclusion where the mesiobuccal cusp of the upper first molar occludes anterior to the buccal groove of the lower first molar?

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

Correct answer: Class II

Angle Class II malocclusion is defined by a distal relationship of the mandible, where the maxillary first molar is ahead (mesial) of its ideal position relative to the mandibular first molar.

Question 194: Which histopathologic finding is pathognomonic for herpes simplex virus infection in oral epithelium?

Multinucleated giant cells with intranuclear inclusions (Cowdry type A) (Correct answer)
Dowling bodies in the basal layer
Acantholytic cells (Tzanck cells) without inclusions
Koilocytes with perinuclear halos

Correct answer: Multinucleated giant cells with intranuclear inclusions (Cowdry type A)

HSV infection produces multinucleated giant cells with ground-glass intranuclear inclusions (Cowdry type A) due to viral replication pushing chromatin to the nuclear periphery.

Question 195: You are creating an occlusal rest seat on the left first premolar of the mandible for a partial cobalt chrome denture. Which of the following best defines the ideal depth at which the marginal ridge should be decreased?

2.0 mm
0.5 mm
1.5 mm (Correct answer)
1.0 mm

Correct answer: 1.5 mm

An ideal occlusal rest seat for a partial cobalt chrome denture requires sufficient depth to provide adequate bulk and strength to the metal rest. A depth of 1.5 mm on the marginal ridge ensures that the rest can withstand occlusal forces without fracturing, while also preventing the rest from interfering with the opposing dentition. This dimension allows for proper rigidity and support of the denture.

Question 196: During tooth preparation for a full cast crown, the occlusal reduction for a posterior tooth should generally be:

0.5 mm
1.5–2.0 mm (Correct answer)
3.0–3.5 mm
1.0 mm

Correct answer: 1.5–2.0 mm

Adequate occlusal reduction of 1.5–2.0 mm is required for posterior full cast crowns to provide sufficient metal thickness and strength.

Question 197: A patient returns 1 week after extraction with dry socket. Which clinical feature most confirms this diagnosis?

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

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 198: Which salivary gland neoplasm is the most common malignant tumor of the parotid gland?

Adenoid cystic carcinoma
Warthin tumor
Acinic cell carcinoma
Mucoepidermoid carcinoma (Correct answer)

Correct answer: Mucoepidermoid carcinoma

Mucoepidermoid carcinoma is the most common malignant salivary gland tumor overall and the most common malignancy of the parotid gland.

Question 199: The Tome's process is an extension of which cell?

Cementoblast
Odontoblast
Fibroblast
Ameloblast (Correct answer)

Correct answer: Ameloblast

Tome's process is the apical cytoplasmic extension of the ameloblast that secretes enamel matrix and determines prism orientation.

Question 200: Which salivary gland produces the highest proportion of serous secretion?

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

Correct answer: Parotid gland

The parotid gland is purely serous and produces approximately 25% of total saliva but nearly all serous secretion.

Question 201: Fibrous dysplasia of the jaw characteristically demonstrates which radiographic appearance?

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

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 202: A patient presents with a white, non-removable plaque-like lesion on the floor of the mouth. Biopsy shows severe epithelial dysplasia. What is the recommended management?

Laser ablation without biopsy
Surgical excision with clear margins (Correct answer)
Antifungal therapy and observation
Observation every 6 months

Correct answer: Surgical excision with clear margins

Severe epithelial dysplasia carries a high risk of malignant transformation and requires surgical excision with clear margins.

Question 203: Which type of bone graft material contains living cells capable of differentiation into osteoblasts?

Allograft
Autograft (Correct answer)
Xenograft
Alloplast

Correct answer: Autograft

Autografts (patient's own bone) contain viable osteogenic cells, osteoinductive factors, and an osteoconductive scaffold, making them the gold standard for bone regeneration.

Question 204: A 25-year-old man is attacked. He has a fracture of the left zygomatic arch and will need surgery. Which of the following muscles is attached to the superior edge of the zygomatic bone's arch?

Temporalis (Correct answer)
Medial pterygoid
Lateral pterygoid
Masseter

Correct answer: Temporalis

The temporalis muscle is a large, fan-shaped muscle of mastication that originates from the temporal fossa and fascia. Its fibers converge into a tendon that passes deep to the zygomatic arch. This tendon inserts onto the coronoid process and anterior border of the ramus of the mandible, making the temporalis muscle's tendon the primary muscle attached to the superior edge of the zygomatic arch as it passes underneath.

Question 205: The incremental lines in dentin that correspond to the neonatal period are called:

Andresen lines
Imbrication lines
Neonatal line (Correct answer)
Owen's contour lines

Correct answer: Neonatal line

The neonatal line is a prominent incremental line in primary teeth dentin marking the abrupt physiologic change at birth.

Question 206: Porcelain-fused-to-metal (PFM) crowns most commonly fracture at which location?

At the connector between adjacent units in a bridge
At the metal-ceramic interface (cohesive failure)
Within the occlusal porcelain over functional contacts (Correct answer)
At the facial margin-porcelain junction

Correct answer: Within the occlusal porcelain over functional contacts

Porcelain fractures most frequently in the occlusal porcelain in areas bearing functional load, as ceramic is brittle and has low tensile strength under repeated occlusal stress.

Question 207: 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:

Candidiasis
Chemical burn
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 208: Which sort of study gives the strongest evidence for making judgments about patient treatment?

Cohort
Systematic review (Correct answer)
Case control
Evidence summary

Correct answer: Systematic review

In the hierarchy of evidence, systematic reviews and meta-analyses provide the strongest evidence for clinical decision-making. They synthesize findings from multiple high-quality primary studies (like randomized controlled trials) on a specific topic, reducing bias and increasing the reliability and generalizability of the conclusions. This comprehensive approach offers the most robust basis for judgments about patient treatment.

Question 209: During a crown preparation, the dentist notices the preparation has a 2-degree taper. What is the clinical consequence?

No clinical consequence; 2 degrees is ideal
The preparation may lack adequate retention (Correct answer)
The crown will have poor aesthetics
The crown will have excessive retention, risking fracture

Correct answer: The preparation may lack adequate retention

Optimal taper for crown preparations is 10–20 degrees; a 2-degree taper makes seating the crown difficult and may impede full seating.

Question 210: One of her close relatives passed away from mouth cancer, and the 32-year-old woman does not smoke or consume alcohol. She has asked you for guidance on preventing oral cancer. Which of the following is most likely to lower her chances of acquiring oral carcinoma?

Take a multi-vitamin tablet daily.
Eat at least five portions of fruit or vegetables daily. (Correct answer)
Maintain excellent oral hygiene.
Avoid spicy food.

Correct answer: Eat at least five portions of fruit or vegetables daily.

A diet rich in fruits and vegetables provides antioxidants and other protective compounds that can help reduce the risk of various cancers, including oral cancer. While good oral hygiene is important for overall oral health, and multivitamins might supplement, a balanced diet with ample produce has stronger evidence for cancer prevention. Avoiding spicy food has no direct link to oral cancer prevention.

Question 211: Necrotizing ulcerative gingivitis (NUG) is caused by synergistic infection involving which organisms?

Porphyromonas gingivalis alone
Spirochetes (Treponema) and fusiform bacteria (Fusobacterium nucleatum) (Correct answer)
Streptococcus mutans and Lactobacillus acidophilus
Actinomyces israelii and Candida albicans

Correct answer: Spirochetes (Treponema) and fusiform bacteria (Fusobacterium nucleatum)

NUG is a polymicrobial anaerobic infection with spirochetes and fusiform bacteria (Fusobacterium-spirochete complex) as the principal causative agents.

Question 212: Which cell type in dental pulp is responsible for synthesizing collagen type III (reticulin fibers)?

Fibroblasts (Correct answer)
Odontoblasts
Macrophages
Dendritic cells

Correct answer: Fibroblasts

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

Question 213: A 39-year-old man with severe anxiety goes to the dentist for treatment. His doctor has suggested medicine to help him control his generalized anxiety problem in the long run. Which of the following medicines has his doctor most likely given him?

Amitriptyline
Diazepam
Fluoxetine (Correct answer)
Clozapine

Correct answer: Fluoxetine

Fluoxetine is a Selective Serotonin Reuptake Inhibitor (SSRI) commonly prescribed for the long-term management of generalized anxiety disorder and depression. While benzodiazepines like diazepam are used for acute anxiety, SSRIs are preferred for chronic conditions due to their efficacy in sustained symptom reduction and lower risk of dependence. Clozapine is an antipsychotic, and amitriptyline is a tricyclic antidepressant, less commonly first-line for GAD.

Question 214: A dentist is treating a patient who is 4 months pregnant. Which radiographs are safe to take if clinically indicated?

No radiographs should ever be taken during pregnancy
Only panoramic radiographs are allowed
Only bitewing radiographs are allowed in the third trimester
Radiographs are safe with proper shielding when diagnostically necessary (Correct answer)

Correct answer: Radiographs are safe with proper shielding when diagnostically necessary

Dental radiographs are safe during pregnancy when clinically necessary, provided a thyroid collar and lead apron are used to minimize fetal exposure.

Question 215: Non-nutritive sucking habits (thumb, finger, or pacifier) begin causing skeletal malocclusion risk primarily when:

The habit begins in the neonatal period
The habit is performed during sleep only
Any habit lasting more than 6 months in a primary dentition
The habit persists beyond the eruption of permanent incisors (approximately age 6–7) (Correct answer)

Correct answer: The habit persists beyond the eruption of permanent incisors (approximately age 6–7)

Non-nutritive sucking during the primary dentition rarely causes permanent skeletal changes; skeletal open bite and Class II risk significantly increase if the habit persists into the permanent dentition.

Question 216: The path of insertion of a complete denture is established perpendicular to:

The mean foundation plane of the residual ridges (Correct answer)
The incisal plane of the anterior teeth
The Frankfort horizontal plane
The occlusal plane of the posterior teeth

Correct answer: The mean foundation plane of the residual ridges

The path of insertion of a complete denture is determined perpendicular to the mean foundation plane, ensuring maximum border seal and minimal tissue displacement.

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.

500

Questions

750 min

Time Limit

75%

To Pass

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