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Egypt Dentistry Licensure Exam study materials
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Egypt Dentistry Licensure Exam practice questions

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Question 1Oral and Maxillofacial Surgery

A 24-year-old patient develops trismus and swelling of the floor of the mouth with elevation of the tongue after a lower molar infection. Which fascial space infection is the most immediate threat to the airway?

  1. Unilateral buccal space abscess
  2. Ludwig's angina involving the submandibular and sublingual spaces bilaterally Correct answer.
  3. Localized alveolar osteitis of the extraction socket
  4. Chronic apical periodontitis with a sinus tract

Explanation

Bilateral involvement of the submandibular and sublingual spaces produces a brawny, board-like swelling of the floor of the mouth that elevates and posteriorly displaces the tongue, directly threatening the airway. This is the classic presentation of Ludwig's angina and requires urgent airway assessment and surgical decompression.

Question 2Oral and Maxillofacial Surgery

Which local anesthetic property best explains why prilocaine carries a risk of methemoglobinemia at higher doses?

  1. Its metabolism produces o-toluidine, which oxidizes hemoglobin Correct answer.
  2. It contains a vasoconstrictor that reduces hepatic clearance
  3. It is excreted unchanged almost entirely by the kidney
  4. It is an ester hydrolyzed by plasma pseudocholinesterase

Explanation

Prilocaine is an amide anesthetic whose hepatic and pulmonary metabolism generates o-toluidine, a metabolite that oxidizes ferrous iron in hemoglobin to the ferric state, producing methemoglobinemia. Doses above roughly 600 mg in adults increase this risk, and treatment is with methylene blue.

Question 3Oral and Maxillofacial Surgery

During a difficult lower third molar extraction, the crown disappears apically and lingually. What is the most appropriate immediate management?

  1. Irrigate the socket and prescribe antibiotics alone
  2. Close the wound and review the patient in one week
  3. Obtain imaging to localize the fragment and plan surgical retrieval Correct answer.
  4. Attempt blind retrieval with a curette through the socket

Explanation

A displaced root or crown fragment must be localized radiographically, usually with two views or cone-beam CT, before any retrieval attempt because the lingual and submandibular spaces are at risk. Blind probing can push the fragment deeper or injure adjacent structures.

Question 4Oral and Maxillofacial Surgery

Which finding on a panoramic radiograph most strongly suggests an increased risk of inferior alveolar nerve injury during third molar removal?

  1. A wide periodontal ligament space around the distal root
  2. Deep root curvature with a narrow follicular space
  3. A horizontal impaction with a fully formed crown
  4. Root apices overlapping the mandibular canal with interruption of the canal's white line Correct answer.

Explanation

Loss of the radiopaque cortical outline of the mandibular canal where roots overlap it indicates close proximity or actual invasion of the canal and raises the risk of nerve injury. Such cases warrant cone-beam CT and consideration of coronectomy or an alternative plan.

Question 5Oral and Maxillofacial Surgery

A patient on warfarin for a mechanical heart valve needs a simple extraction. The INR is 3.2. What is the most appropriate approach?

  1. Stop warfarin five days preoperatively without bridging
  2. Give fresh frozen plasma in the dental chair and extract immediately
  3. Double the warfarin dose to stabilize the INR before surgery
  4. Proceed with extraction using local measures and consult the physician about bridging or dose adjustment Correct answer.

Explanation

An INR of 3.2 exceeds the range generally accepted for simple dentoalveolar surgery, and the patient has a high thrombotic risk from a mechanical valve. The correct step is interdisciplinary discussion about bridging or dose adjustment while using local hemostatic measures such as sutures, oxidized cellulose, and tranexamic mouthwash.

Question 6Oral and Maxillofacial Surgery

Which antibiotic regimen is recommended for a patient with a documented penicillin allergy who requires prophylaxis before dental extraction for a prosthetic heart valve?

  1. Clindamycin 600 mg orally
  2. Amoxicillin 2 g orally
  3. Azithromycin or clarithromycin 500 mg orally Correct answer.
  4. Cephalexin 2 g orally

Explanation

Current guidance for patients with penicillin allergy who need infective endocarditis prophylaxis lists a macrolide such as azithromycin or clarithromycin, or doxycycline, as acceptable alternatives. Clindamycin is no longer recommended for this purpose because of severe adverse effects.

Question 7Oral and Maxillofacial Surgery

A patient reports persistent numbness of the lower lip and chin six months after surgical removal of an impacted lower third molar. Which nerve is most likely injured?

  1. Mylohyoid nerve
  2. Buccal nerve
  3. Lingual nerve
  4. Inferior alveolar nerve Correct answer.

Explanation

The inferior alveolar nerve supplies sensation to the lower teeth, lower lip, and chin, so its injury produces the described distribution of numbness. Lingual nerve injury instead causes loss of sensation on the anterior two-thirds of the tongue and taste disturbance.

Question 8Oral and Maxillofacial Surgery

Which clinical feature most reliably differentiates a periapical cyst from a periapical granuloma before histologic examination?

  1. Mild tenderness to percussion
  2. Presence of a nonvital pulp in the associated tooth
  3. History of previous endodontic treatment
  4. Size greater than 10 mm with a well-defined radiolucent border Correct answer.

Explanation

Cysts and granulomas cannot be reliably distinguished clinically, but a lesion larger than about 10 mm with a well-circumscribed radiolucent border is more suggestive of a cyst. Definitive diagnosis still requires histopathology after enucleation.

Question 9Oral and Maxillofacial Surgery

Which of the following is the most common odontogenic cyst of the jaws?

  1. Odontogenic keratocyst
  2. Radicular cyst Correct answer.
  3. Lateral periodontal cyst
  4. Dentigerous cyst

Explanation

The radicular cyst, also called a periapical cyst, is the most common odontogenic cyst and arises from epithelial rests in a periapical granuloma of a nonvital tooth. It accounts for the majority of inflammatory odontogenic cysts.

Question 10Oral and Maxillofacial Surgery

A 55-year-old smoker presents with a painless, indurated ulcer on the lateral border of the tongue that has persisted for six weeks. What is the most appropriate next step?

  1. Reassess after removing a presumed irritant for one month
  2. Perform an incisional biopsy of the lesion Correct answer.
  3. Reassure the patient that it is a traumatic ulcer
  4. Prescribe a topical corticosteroid and review in two weeks

Explanation

Any ulcer persisting beyond two to three weeks, especially in a smoker on the lateral tongue, must be regarded as suspicious for squamous cell carcinoma. Incisional biopsy provides the diagnosis, and referral to an oral and maxillofacial surgeon or oncology service follows.

Question 11Oral and Maxillofacial Surgery

Which imaging modality is most appropriate for evaluating the extent of bony invasion in a suspected oral squamous cell carcinoma involving the mandible?

  1. Ultrasound of the neck
  2. Panoramic radiography alone
  3. Periapical radiography
  4. Contrast-enhanced CT or MRI with bone assessment Correct answer.

Explanation

Cross-sectional imaging with contrast-enhanced CT or MRI is required to assess bone invasion, soft tissue extent, and regional lymph nodes for staging and surgical planning. Plain films lack the sensitivity and three-dimensional detail needed for this decision.

Question 12Oral and Maxillofacial Surgery

Which technique is most appropriate for reducing a bilateral anterior mandibular fracture with significant displacement?

  1. Open reduction and internal fixation through an intraoral approach Correct answer.
  2. Observation with a soft diet
  3. Closed reduction with maxillomandibular fixation alone
  4. Manual reduction with a pressure bandage

Explanation

Displaced bilateral anterior mandibular fractures generally require open reduction and internal fixation to restore occlusion and stability, and an intraoral approach avoids a facial scar. Maxillomandibular fixation alone is less reliable for displaced or unstable patterns.

Question 13Oral and Maxillofacial Surgery

A patient sustains a blow to the chin and presents with a step deformity at the lower border of the mandible, anterior open bite, and bilateral sublingual ecchymosis. Which fracture pattern is most likely?

  1. Zygomatic arch fracture
  2. Le Fort I fracture
  3. Unilateral condylar neck fracture
  4. Bilateral parasymphyseal fracture Correct answer.

Explanation

A blow to the chin commonly produces bilateral parasymphyseal fractures, which present with a step at the lower border, an anterior open bite from muscle pull, and sublingual hematoma. The chin acts as the fulcrum transmitting force to both sides of the symphysis.

Question 14Oral and Maxillofacial Surgery

Which suture material is most appropriate for closure of the oral mucosa when prolonged tensile strength is not required and resorption within two to three weeks is desirable?

  1. Chromic gut 3-0 Correct answer.
  2. Nylon 4-0
  3. Silk 3-0
  4. Polypropylene 4-0

Explanation

Chromic gut is an absorbable suture that loses strength and resorbs over two to three weeks, which suits mucosal closure where the patient cannot return for removal. Silk is nonabsorbable and braided, and nylon and polypropylene are nonabsorbable monofilaments.

Question 15Oral and Maxillofacial Surgery

Which flap design is preferred for surgical removal of a palatally impacted maxillary canine with adequate palatal space?

  1. Labial envelope flap with apically positioned sutures
  2. Subperiosteal tunneling from the buccal vestibule
  3. Crestal incision without vertical release
  4. Palatal flap with a relieving incision and careful preservation of the greater palatine neurovascular bundle Correct answer.

Explanation

A palatal approach gives direct access to a palatally impacted canine, but the flap must be designed to avoid the greater palatine neurovascular bundle, which exits near the second molar region. Careful incision planning preserves vascularity and sensation of the palate.

Question 16Oral and Maxillofacial Surgery

Which of the following best describes the mechanism of action of tranexamic acid in controlling post-extraction bleeding?

  1. It directly constricts the bleeding vessel wall
  2. It promotes platelet aggregation through ADP receptors
  3. It activates vitamin K-dependent clotting factors
  4. It inhibits fibrinolysis by blocking plasminogen binding to fibrin Correct answer.

Explanation

Tranexamic acid is an antifibrinolytic that binds plasminogen and prevents its conversion to plasmin, stabilizing the clot in the socket. A 4.8% mouthwash used several times daily is a common adjunct after extraction in anticoagulated patients.

Question 17Oral and Maxillofacial Surgery

A patient with uncontrolled type 2 diabetes and an HbA1c of 10% needs multiple extractions. What is the most important consideration before surgery?

  1. Proceed immediately because dental infection is urgent
  2. Optimize glycemic control in consultation with the physician before elective surgery Correct answer.
  3. Give a single dose of insulin in the dental clinic
  4. Avoid local anesthesia entirely

Explanation

Poor glycemic control impairs wound healing and increases the risk of infection and postoperative complications, so elective surgery should be deferred until control improves. The dentist coordinates with the physician while treating acute infection with drainage and antibiotics if needed.

Question 18Oral and Maxillofacial Surgery

Which clinical sign most strongly suggests a malignant rather than a benign salivary gland neoplasm of the parotid?

  1. Bilateral diffuse enlargement
  2. Facial nerve palsy on the affected side Correct answer.
  3. A slowly enlarging, mobile, well-defined mass
  4. A soft, fluctuant swelling that resolves with sialagogues

Explanation

Facial nerve involvement in a parotid mass indicates malignant infiltration of the nerve and is a red flag for malignancy. Benign tumors such as pleomorphic adenoma typically present as slow-growing, mobile masses without nerve deficit.

Question 19Oral and Maxillofacial Surgery

Which of the following is a recognized indication for coronectomy rather than complete removal of a lower third molar?

  1. A horizontally impacted third molar with a periapical infection
  2. A mesioangular impaction with no radiographic proximity to the canal
  3. A fully erupted third molar with caries
  4. A vital third molar whose roots intimately overlap the mandibular canal Correct answer.

Explanation

Coronectomy removes the crown and leaves vital roots in place to avoid inferior alveolar nerve injury when roots are intimately related to the canal. It is contraindicated when the tooth is infected or nonvital because retained roots may then become a source of infection.

Question 20Oral and Maxillofacial Surgery

A patient presents with a unilateral dislocated temporomandibular joint after a wide yawn, with inability to close the mouth and deviation of the chin to the opposite side. What is the most appropriate initial management?

  1. Application of a cervical collar and observation
  2. Injection of botulinum toxin into the masseter
  3. Manual reduction after appropriate analgesia and muscle relaxation Correct answer.
  4. Immediate open reduction under general anesthesia

Explanation

Acute anterior dislocation is treated by manual reduction, usually after analgesia and relaxation, using downward and backward pressure on the mandible. General anesthesia is reserved for cases that cannot be reduced with conservative measures.

Question 21Oral and Maxillofacial Surgery

Which of the following is the most appropriate first-line treatment for a patient with an acute temporomandibular joint disc displacement without reduction and no improvement after two weeks of conservative care?

  1. Permanent maxillomandibular fixation
  2. Continued conservative therapy with physical therapy, NSAIDs, and a soft diet Correct answer.
  3. Immediate open joint surgery
  4. Bilateral condylectomy

Explanation

Most acute disc displacements without reduction respond to conservative measures such as physical therapy, NSAIDs, muscle relaxants, and a soft diet over several weeks. Surgery is considered only after conservative treatment fails and symptoms are disabling.

Question 22Oral and Maxillofacial Surgery

Which nerve block provides anesthesia to the anterior two-thirds of the tongue and the lingual gingiva of the mandible?

  1. Long buccal nerve block
  2. Mental nerve block
  3. Inferior alveolar nerve block alone
  4. Lingual nerve block Correct answer.

Explanation

The lingual nerve supplies general sensation to the anterior two-thirds of the tongue and the lingual gingiva, and it is anesthetized by depositing solution near it during an inferior alveolar block. The inferior alveolar block alone anesthetizes the teeth and lip but not the tongue.

Question 23Oral and Maxillofacial Surgery

Which of the following is the most reliable clinical test for confirming a diagnosis of dry socket after a lower molar extraction?

  1. Presence of severe throbbing pain with an empty socket and exposed bone beginning on the second to fourth postoperative day Correct answer.
  2. Fever above 38.5°C with facial swelling
  3. Positive pulp vitality test of the adjacent tooth
  4. Radiographic evidence of a retained root

Explanation

Alveolar osteitis presents with severe throbbing pain that increases after the second postoperative day, an empty socket, and exposed bone, often with a foul odor. Fever and facial swelling instead suggest a spreading infection rather than a dry socket.

Question 24Oral and Maxillofacial Surgery

A patient with a mandibular fracture is found to have a mobile, anteriorly displaced segment and a compromised airway. What is the most appropriate immediate priority?

  1. Obtain a panoramic radiograph before any intervention
  2. Prescribe antibiotics and schedule review in 24 hours
  3. Secure the airway and stabilize the mandibular segment Correct answer.
  4. Apply arch bars and discharge the patient

Explanation

Airway compromise takes precedence over imaging or definitive fixation in maxillofacial trauma, following the ATLS principle of airway first. The mandibular segment may need temporary stabilization or the patient may require intubation before imaging and repair.

Question 25Oral and Maxillofacial Surgery

Which of the following best explains why a patient with a history of bisphosphonate therapy may develop osteonecrosis of the jaw after extraction?

  1. Bisphosphonates are metabolized in the liver to toxic metabolites
  2. Bisphosphonates cause immediate necrosis of the oral mucosa
  3. Bisphosphonates directly infect the socket with bacteria
  4. Bisphosphonates inhibit osteoclast function and impair bone remodeling and healing Correct answer.

Explanation

Bisphosphonates accumulate in bone and inhibit osteoclast-mediated resorption, impairing remodeling and healing after trauma such as extraction. This can lead to exposed nonhealing bone, especially in patients on high-dose intravenous therapy for malignancy.

Question 26Oral and Maxillofacial Surgery

A 24-year-old woman attends the emergency clinic with a swollen, painful upper lip and a fluctuant swelling of the upper buccal vestibule over the incisor region. She has a history of recurrent furuncles. Which diagnosis best fits this presentation?

  1. Nasolabial cyst Correct answer.
  2. Recurrent apical abscess of odontogenic origin
  3. Facial cellulitis of dental origin
  4. Maxillary sinus mucocele

Explanation

A nasolabial cyst is a developmental soft-tissue cyst that lies in the nasolabial fold and classically presents as a painless or tender fluctuant swelling that obliterates the labial vestibule and elevates the ala of the nose; it is not of dental origin and the teeth remain vital. Because it is confined to soft tissue, there is no bony involvement on imaging. The history of recurrent skin infections is a distractor and does not change the anatomical diagnosis.

Question 27Oral and Maxillofacial Surgery

A 32-year-old man has a displaced mandibular parasymphysis fracture. The fracture line runs obliquely through the region of the mental foramen, and the inferior border shows a 4 mm step. Which fixation plan best restores the biomechanics of this region while preserving the inferior alveolar nerve?

  1. Two miniplates placed on the inferior border, one of which crosses the mental foramen
  2. A tension band plate at the alveolar border combined with an inferior border plate placed below the mental foramen Correct answer.
  3. A single noncompression plate applied to the inferior border with bicortical screws across the fracture
  4. A single monocortical miniplate placed along the superior border above the mental foramen

Explanation

The anterior mandible is subjected to tensile forces at the alveolar border and compressive forces at the inferior border during function, so stable fixation requires a tension band plate superiorly and a load-bearing plate at the inferior border. Placing the inferior plate below the mental foramen avoids injury to the inferior alveolar nerve while restoring the contour of the lower border. This two-plate configuration is the accepted standard for parasymphyseal fractures.

Question 28Oral and Maxillofacial Surgery

A 45-year-old woman with a long-standing history of recurrent swelling of the submandibular region undergoes sialography. The image shows a dilated main duct with multiple strictures and alternating areas of dilatation of the intraglandular ducts. Which condition is most consistent with these findings?

  1. Chronic sialadenitis of the submandibular gland Correct answer.
  2. Sialolithiasis with a single obstructing calculus
  3. Pleomorphic adenoma of the submandibular gland
  4. Sjögren syndrome affecting the submandibular gland

Explanation

Chronic sialadenitis produces a characteristic sialographic appearance of ductal ectasia with strictures and a beaded, irregular ductal pattern reflecting repeated inflammation and fibrosis. The history of recurrent swelling supports this diagnosis. Sialography is used diagnostically because it outlines the ductal architecture, and the alternating dilatation and narrowing is the hallmark described.

Question 29Restorative Dentistry and Endodontics

A 28-year-old patient has a deep occlusal carious lesion in a mandibular first molar. The pulp is vital, there is no spontaneous pain, and a radiograph shows a radiolucent zone limited to the enamel and outer dentin. Which treatment approach is most appropriate?

  1. Immediate root canal treatment followed by a post-retained crown
  2. Indirect pulp capping with no restoration placed at the same visit
  3. Complete excavation of all softened dentin until the pulp is visible
  4. Selective caries removal leaving firm affected dentin at the pulpal floor Correct answer.

Explanation

In a vital, asymptomatic tooth with caries approaching but not exposing the pulp, contemporary practice is selective removal: soft infected dentin is excavated peripherally while firm, leathery affected dentin is retained over the pulp to avoid exposure. This preserves pulpal vitality and reduces the risk of iatrogenic exposure. The retained dentin is then sealed with an adhesive restoration.

Question 30Restorative Dentistry and Endodontics

Which base material is contraindicated beneath a composite resin restoration in a deep cavity because it interferes with light transmission and adhesive bonding?

  1. Calcium hydroxide liner
  2. Flowable composite
  3. Zinc oxide-eugenol cement Correct answer.
  4. Resin-modified glass ionomer

Explanation

Zinc oxide-eugenol cements are opaque, interfere with the polymerization of resin-based materials, and are not used as a base under composites. They also have a weak bond to adhesive systems. They remain useful as temporary or sedative materials but not as a base beneath composite.

Question 31Restorative Dentistry and Endodontics

During preparation of a Class II cavity in a maxillary premolar, the proximal box is extended to the buccal and lingual embrasures. Which function does this extension primarily serve?

  1. Providing resistance form against occlusal forces
  2. Allowing visual access for caries removal and finishing Correct answer.
  3. Preventing the restoration from being displaced cervically
  4. Increasing retention form by creating a dovetail

Explanation

Extending the proximal box into the embrasures provides clearance so the operator can see, instrument, and finish the gingival seat and margins. It also creates a clean enamel margin where a matrix can be adapted. Retention and resistance are achieved by other features such as the dovetail and pulpal floor depth.

Question 32Restorative Dentistry and Endodontics

Which dentin bonding step is most critical for achieving a durable bond with an etch-and-rinse adhesive?

  1. Maintaining a visibly moist dentin surface after rinsing Correct answer.
  2. Curing the adhesive before solvent evaporation
  3. Overdrying the dentin thoroughly with warm air
  4. Applying the primer only to enamel margins

Explanation

After acid etching and rinsing, dentin should remain moist so that collagen fibrils stay expanded and the primer can infiltrate the demineralized layer. Overdrying causes collagen collapse and leaves voids in the hybrid layer. Solvent must also be evaporated before light curing.

Question 33Restorative Dentistry and Endodontics

Which matrix system is most appropriate for restoring a Class II cavity in a primary molar with a proximal box that extends below the gingival margin?

  1. Sectional metal matrix with a wedge Correct answer.
  2. Transparent plastic matrix with no retainer
  3. Celluloid strip alone
  4. Preformed stainless steel crown

Explanation

A sectional metal matrix with a wedge provides contour, prevents overhang, and stabilizes the restoration in deep proximal boxes. Celluloid or plastic strips alone cannot restore proper proximal contour in a box that extends subgingivally. Stainless steel crowns are a full-coverage restoration, not a matrix.

Question 34Restorative Dentistry and Endodontics

A patient reports sharp pain lasting a few seconds after drinking cold water; the pain disappears immediately when the stimulus is removed. Which pulpal diagnosis best matches this presentation?

  1. Reversible pulpitis Correct answer.
  2. Asymptomatic irreversible pulpitis
  3. Pulpal necrosis
  4. Symptomatic irreversible pulpitis

Explanation

Reversible pulpitis is characterized by sharp, stimulus-provoked pain that resolves promptly once the stimulus is removed, and the pulp remains vital. Irreversible pulpitis produces lingering pain, often spontaneous. Necrosis produces no response to thermal testing.

Question 35Restorative Dentistry and Endodontics

Which condition is a contraindication to performing vital pulp therapy with a direct pulp cap?

  1. A vital pulp with no periapical radiolucency
  2. An exposure created during caries excavation in a symptom-free tooth
  3. A small mechanical exposure in a young, healthy pulp
  4. Uncontrolled hemorrhage from the exposure site after hemostasis attempts Correct answer.

Explanation

Persistent hemorrhage that cannot be controlled indicates a pulp that is inflamed beyond superficial layers and is unlikely to heal under a direct cap. In such cases, pulpotomy or root canal treatment is preferred. Young, vital pulps with controllable bleeding are favorable candidates.

Question 36Restorative Dentistry and Endodontics

Which irrigant is the primary choice for dissolving organic tissue and disinfecting the root canal system during chemomechanical preparation?

  1. 17% EDTA
  2. Chlorhexidine gluconate 2%
  3. 2.5% sodium hypochlorite Correct answer.
  4. 0.9% sodium chloride

Explanation

Sodium hypochlorite is the main endodontic irrigant because it dissolves necrotic tissue and has broad antimicrobial activity. It is typically used at concentrations between 1% and 5.25%. EDTA is used for smear layer removal, not as the primary tissue solvent.

Question 37Restorative Dentistry and Endodontics

During root canal treatment of a mandibular first molar, the clinician notes a small, separate canal located between the mesiobuccal and mesiolingual canals. Which canal is this most likely to be?

  1. Middle mesial canal Correct answer.
  2. Second distal canal
  3. Radix entomolaris canal
  4. Distobuccal canal

Explanation

A middle mesial canal lies between the mesiobuccal and mesiolingual canals in mandibular molars and is present in a significant minority of teeth. Its identification improves cleaning of the mesial root. Radix entomolaris is an additional distolingual root, not a middle mesial canal.

Question 38Restorative Dentistry and Endodontics

Which working length determination method is most reliable when the apical constriction is difficult to identify radiographically?

  1. Electronic apex locator combined with a confirmatory radiograph Correct answer.
  2. Estimating from the average tooth length table
  3. Feeling for a sudden drop in resistance with a paper point
  4. Tactile sensation with a large file

Explanation

Electronic apex locators are accurate in most clinical situations and are best combined with a confirmatory radiograph. This dual approach reduces the risk of over- or under-instrumentation. Tactile methods and average length tables are unreliable in complex anatomy.

Question 39Restorative Dentistry and Endodontics

Which file motion is characteristic of the balanced force technique during root canal instrumentation?

  1. Vertical reciprocation with no rotation
  2. Ultrasonic activation of an irrigant
  3. Quarter-turn clockwise followed by a larger counterclockwise rotation Correct answer.
  4. Continuous rotation with light apical pressure

Explanation

Balanced force technique uses a quarter-turn clockwise to engage dentin, followed by a larger counterclockwise rotation to cut and remove debris while keeping the file engaged. This reduces the risk of transporting curved canals. Continuous rotation describes rotary nickel-titanium systems.

Question 40Restorative Dentistry and Endodontics

A patient presents with severe pain, swelling of the buccal vestibule, and a fluctuant mass adjacent to a mandibular molar with a necrotic pulp. Which is the most appropriate immediate management?

  1. Obturation of the canal without drainage
  2. Topical fluoride varnish application
  3. Immediate placement of a permanent restoration
  4. Incision and drainage with systemic antibiotics and later endodontic treatment Correct answer.

Explanation

A fluctuant swelling indicates an abscess that requires incision and drainage to relieve pressure and allow pus evacuation. Systemic antibiotics are indicated when there is spreading infection or systemic involvement, and endodontic treatment follows. Restoring or obturating without drainage would not address the acute infection.

Question 41Restorative Dentistry and Endodontics

Which property of gutta-percha makes it suitable as a core obturating material?

  1. It bonds chemically to dentin
  2. It resists dissolution by all solvents
  3. It is thermoplastic and adapts to canal walls under heat or pressure Correct answer.
  4. It completely seals the canal without sealer

Explanation

Gutta-percha becomes plastic when heated and can be compacted or injected to adapt to canal irregularities. It does not bond to dentin and requires a sealer to fill the gaps between the material and the canal wall. It is soluble in chloroform and other solvents.

Question 42Restorative Dentistry and Endodontics

Which factor most strongly increases the risk of a vertical root fracture in an endodontically treated tooth?

  1. Use of a small-diameter file during shaping
  2. Placement of a coronal restoration within one week
  3. Excessive removal of radicular dentin during post space preparation Correct answer.
  4. Use of a rubber dam during treatment

Explanation

Removing excessive radicular dentin weakens the root and increases susceptibility to vertical root fracture. Post space preparation should preserve at least 4 to 5 mm of apical gutta-percha and leave adequate dentin thickness. Rubber dam use and timely restoration are protective, not harmful.

Question 43Restorative Dentistry and Endodontics

Which esthetic consideration most influences shade matching for a maxillary central incisor restoration?

  1. Selecting the shade after prolonged rubber dam isolation
  2. Matching the shade to the gingival third only
  3. Selecting the shade under a bright dental operating light
  4. Selecting the shade before the tooth is desiccated and under neutral daylight Correct answer.

Explanation

Shade should be selected before the tooth dries out and under neutral daylight, because desiccation and colored lighting shift perceived shade. Prolonged isolation dehydrates enamel and makes it appear lighter. The middle third is typically used for shade matching.

Question 44Restorative Dentistry and Endodontics

Which type of tooth preparation is required for a ceramic laminate veneer on a maxillary central incisor?

  1. A Class III preparation with a lingual dovetail
  2. Removal of the entire incisal edge and lingual surface
  3. Minimal facial reduction of 0.3 to 0.5 mm within enamel Correct answer.
  4. Full-coverage crown preparation with a 1.5 mm shoulder

Explanation

Laminate veneers require conservative facial reduction, typically 0.3 to 0.5 mm, ideally within enamel to maximize bonding. Full-coverage or extensive lingual reduction is unnecessary and sacrifices tooth structure. Enamel bonding is essential for durable adhesion.

Question 45Restorative Dentistry and Endodontics

Which feature distinguishes a Class IV cavity preparation from a Class III preparation?

  1. Involvement of the cervical third of the facial surface
  2. Involvement of the occlusal pit and fissure
  3. Involvement of the proximal surface only
  4. Involvement of the incisal angle in addition to the proximal surface Correct answer.

Explanation

A Class IV preparation includes the proximal surface and the incisal angle of an anterior tooth, whereas a Class III is proximal only. Class V involves the cervical third, and Class I involves pits and fissures. The incisal angle involvement affects retention and esthetics.

Question 46Restorative Dentistry and Endodontics

Which factor most limits the success of a direct composite restoration in a large posterior cavity?

  1. Incremental curing with a light-curing unit
  2. Use of a rubber dam during placement
  3. Polymerization shrinkage leading to marginal leakage and postoperative sensitivity Correct answer.
  4. Excessive enamel thickness at the margins

Explanation

Polymerization shrinkage of composite creates stress at the bonded interface, potentially causing marginal leakage, postoperative sensitivity, and recurrent caries. Incremental placement and proper curing reduce but do not eliminate this effect. Enamel thickness and isolation support success.

Question 47Restorative Dentistry and Endodontics

Which instrument is most appropriate for removing carious dentin from the pulpal floor of a deep cavity while minimizing the risk of pulp exposure?

  1. A spoon excavator used with light pressure Correct answer.
  2. A periodontal curette
  3. A diamond bur with coarse grit
  4. A large round carbide bur at high speed

Explanation

A spoon excavator allows controlled removal of soft caries near the pulp with minimal risk of mechanical exposure. High-speed burs and coarse diamonds remove dentin aggressively and can expose the pulp. A periodontal curette is designed for root surface debridement, not caries excavation.

Question 48Restorative Dentistry and Endodontics

Which radiographic finding is most consistent with a chronic periapical abscess associated with a necrotic pulp?

  1. No radiographic changes in any circumstance
  2. A well-defined radiolucency at the apex with a sclerotic border Correct answer.
  3. A widened periodontal ligament space with no bone loss
  4. Diffuse radiolucency confined to the crown

Explanation

A chronic periapical abscess typically shows a well-defined periapical radiolucency, often with a sclerotic border reflecting slow, long-standing bone resorption. Widened PDL space alone is nonspecific. Crown radiolucency indicates caries, not apical pathology.

Question 49Restorative Dentistry and Endodontics

Which factor is most important for the long-term success of a fiber post used to restore an endodontically treated anterior tooth?

  1. Complete removal of all gutta-percha before post placement
  2. Cementation with zinc phosphate without dentin bonding
  3. Preservation of at least 4 to 5 mm of apical gutta-percha and a ferrule Correct answer.
  4. Use of a post that extends to the apical foramen

Explanation

Retention of an adequate apical seal and a circumferential ferrule of sound dentin are key to success with fiber posts. The ferrule resists lever forces and reduces root fracture risk. Removing all gutta-percha or extending the post to the apex compromises the seal.

Question 50Restorative Dentistry and Endodontics

Which pulp capping material is preferred for direct pulp capping because it induces reparative dentin formation and maintains a seal?

  1. Amalgam
  2. Calcium hydroxide or a calcium silicate cement Correct answer.
  3. Eugenol-based temporary cement
  4. Zinc phosphate cement

Explanation

Calcium hydroxide and calcium silicate cements stimulate reparative dentin formation and provide a seal over the exposure. Calcium silicates such as MTA have shown favorable outcomes and better sealing ability. Zinc phosphate, amalgam, and eugenol cements do not promote dentin bridge formation.