Endodontics Prometric exam questions with answers

1. Question 1Cleaning, Shaping and Irrigationmedium

   During irrigation of tooth 15, the patient suddenly reports severe pain, followed within minutes by facial swelling and ecchymosis. What is the most appropriate immediate management?

   1. AStop irrigating, reassure, give analgesia and apply cold compresses
   2. BContinue irrigation with saline to dilute the hypochlorite
   3. CApply heat packs immediately to promote resorption
   4. DExtract the tooth immediately to drain the area
   Show answer and explanation▾

   Answer: A. Stop irrigating, reassure, give analgesia and apply cold compresses

   Management of sodium hypochlorite extrusion is to stop treatment, reassure, provide local anaesthesia and analgesia, apply cold compresses initially and monitor, with referral if the airway is threatened. Further irrigation risks forcing more irritant into the tissues.

2. Question 2Cleaning, Shaping and Irrigationhard

   Which factor most increases the risk of cyclic fatigue fracture of a rotary nickel-titanium instrument?

   1. AUsing a glide path before rotary files
   2. BA canal with a small radius of curvature
   3. CUsing irrigant during instrumentation
   4. DUsing the file in a straight canal
   Show answer and explanation▾

   Answer: B. A canal with a small radius of curvature

   Cyclic fatigue results from repeated tension-compression cycles as the file rotates in a curve, and a smaller radius of curvature (an abrupt curve) greatly increases the strain. A glide path reduces torsional stress rather than increasing fracture risk.

3. Question 3Dental Trauma and Endodontic Emergenciesmedium

   A 9-year-old has a 3 mm intrusion of maxillary central incisor 11, which has an immature open apex. What is the recommended initial management?

   1. AImmediate surgical repositioning and splint
   2. BImmediate pulpectomy and calcium hydroxide
   3. CExtraction and a removable space maintainer
   4. DAllow spontaneous re-eruption with monitoring
   Show answer and explanation▾

   Answer: D. Allow spontaneous re-eruption with monitoring

   Intruded permanent teeth with immature roots are allowed to re-erupt spontaneously, with orthodontic repositioning considered if there is no movement within about 4 weeks. Immediate pulp extirpation is not indicated because pulp revascularisation is possible in immature teeth.

4. Question 4Obturation and Restoration of Treated Teethmedium

   On a post-obturation radiograph, which root filling length is generally considered acceptable for a tooth with a mature apex?

   1. A3-4 mm short of the radiographic apex
   2. B0-2 mm short of the radiographic apex
   3. C1-2 mm beyond the radiographic apex
   4. DExactly 1 mm beyond the apex
   Show answer and explanation▾

   Answer: B. 0-2 mm short of the radiographic apex

   Root fillings ending 0-2 mm short of the radiographic apex are associated with the best outcomes in teeth with apical periodontitis. Overfilling beyond the apex and fillings more than 2 mm short are both associated with lower success rates.

5. Question 5Root Canal Anatomy and Accesseasy

   During root canal treatment of a maxillary first molar, which canal is most commonly missed and is often located palatal to the main mesiobuccal canal along the groove towards the palatal orifice?

   1. ASecond distobuccal canal
   2. BSecond mesiobuccal canal (MB2)
   3. CSecond palatal canal
   4. DMiddle mesial canal
   Show answer and explanation▾

   Answer: B. Second mesiobuccal canal (MB2)

   The MB2 canal is present in a high proportion of maxillary first molars and is the most frequently missed canal; it lies mesial and palatal to the MB1 orifice along the line to the palatal orifice. Middle mesial canals occur in mandibular molars.

6. Question 6Pulpal and Periapical Diagnosismedium

   Tooth 21 is discoloured and does not respond to cold or electric testing. There is a painless sinus tract on the labial gingiva, and a gutta-percha cone traced through it points to a periapical radiolucency on 21. What is the apical diagnosis?

   1. AChronic apical abscess
   2. BAsymptomatic apical periodontitis
   3. CAcute apical abscess
   4. DCondensing osteitis
   Show answer and explanation▾

   Answer: A. Chronic apical abscess

   A chronic apical abscess is an inflammatory reaction to pulpal infection with gradual onset, little or no discomfort and intermittent drainage through a sinus tract. Asymptomatic apical periodontitis shows a radiolucency without a sinus tract.

7. Question 7Root Canal Anatomy and Accesshard

   During access of a mandibular tooth in a patient of East Asian descent, a single ribbon-shaped orifice forms a 180-degree arc. In which tooth is this C-shaped canal configuration most common?

   1. AMandibular second molar
   2. BMandibular first premolar
   3. CMandibular canine
   4. DMandibular first molar
   Show answer and explanation▾

   Answer: A. Mandibular second molar

   C-shaped canals occur most often in mandibular second molars with fused roots, with higher prevalence in East Asian populations. They are uncommon in first molars, and their fins require thorough irrigation and activation.

8. Question 8Vital Pulp Therapy, Regenerative Endodontics and Pharmacologyeasy

   How many milligrams of lidocaine are contained in one 1.8 mL cartridge of 2% lidocaine with epinephrine?

   1. A18 mg
   2. B20 mg
   3. C72 mg
   4. D36 mg
   Show answer and explanation▾

   Answer: D. 36 mg

   A 2% solution contains 20 mg/mL, so 1.8 mL contains 36 mg of lidocaine. 72 mg is the content of a 1.8 mL cartridge of 4% articaine.

9. Question 9Pulpal and Periapical Diagnosismedium

   A radiograph of tooth 36, which has a large carious lesion and symptoms of irreversible pulpitis, shows a diffuse radiopaque area around the mesial root apex. What is this finding most likely to be?

   1. ACondensing osteitis
   2. BCementoblastoma
   3. CIdiopathic osteosclerosis
   4. DHypercementosis
   Show answer and explanation▾

   Answer: A. Condensing osteitis

   Condensing osteitis is a diffuse radiopaque bony reaction to low-grade pulpal inflammation, usually at the apex of a tooth with pulp disease, and often resolves after root canal treatment. Idiopathic osteosclerosis occurs next to healthy vital teeth with no pulpal pathology.

10. Question 10Retreatment, Surgery and Outcomesmedium

    During apical surgery on a maxillary lateral incisor, how much of the root end should be resected to remove most apical ramifications and lateral canals?

    1. A1 mm
    2. B6 mm
    3. C3 mm
    4. DHalf of the root length
    Show answer and explanation▾

    Answer: C. 3 mm

    Resecting about 3 mm of the root end removes around 98% of apical ramifications and 93% of lateral canals. Resection of 1 mm leaves many ramifications, while larger resection unnecessarily reduces crown-root ratio.

11. Question 11Retreatment, Surgery and Outcomesmedium

    Compared with traditional apicoectomy, why does modern microsurgery use a root-end resection with little or no bevel?

    1. AIt exposes fewer dentinal tubules and reduces leakage
    2. BIt increases the visibility of the apical foramen
    3. CIt allows a larger amalgam root-end filling
    4. DIt removes more lingual root structure
    Show answer and explanation▾

    Answer: A. It exposes fewer dentinal tubules and reduces leakage

    A perpendicular resection with minimal bevel exposes fewer dentinal tubules and reduces apical leakage, while preserving root length; microscopes and ultrasonic tips remove the need for a steep bevel. Steep bevels can also miss lingual anatomy.

12. Question 12Retreatment, Surgery and Outcomesmedium

    A tooth root-filled 3 years ago has a persistent periapical lesion. The root filling is short and poorly condensed, and the crown is clinically sound. What is generally the preferred first treatment?

    1. AApical surgery with root-end filling
    2. BNon-surgical root canal retreatment
    3. CExtraction and implant placement
    4. DSystemic antibiotics and review
    Show answer and explanation▾

    Answer: B. Non-surgical root canal retreatment

    When the existing root filling is inadequate and the canal is accessible, non-surgical retreatment addresses the persistent intracanal infection and is the preferred first option. Apical surgery alone leaves the infected canal contents in place.

13. Question 13Root Canal Anatomy and Accessmedium

    Mandibular incisors frequently have a second canal. Where is this canal usually found and how should access be modified to locate it?

    1. ADistal; extend access towards the distal surface
    2. BLabial; extend access towards the labial surface
    3. CMesial; extend access towards the mesial surface
    4. DLingual; extend access lingually towards the cingulum
    Show answer and explanation▾

    Answer: D. Lingual; extend access lingually towards the cingulum

    The second canal in mandibular incisors is usually lingual, hidden behind the lingual shoulder of dentine, so access should be extended lingually towards the cingulum or incisally. Mesial or distal extension does not uncover it.

14. Question 14Root Canal Anatomy and Accessmedium

    Using an electronic apex locator and confirmatory radiograph, where should working length typically end for a tooth with a necrotic pulp and mature apex?

    1. A2 mm beyond the radiographic apex
    2. BExactly at the radiographic apex
    3. C0.5-1 mm short of the radiographic apex
    4. D4 mm short of the radiographic apex
    Show answer and explanation▾

    Answer: C. 0.5-1 mm short of the radiographic apex

    Working length is usually set 0.5-1 mm short of the radiographic apex, close to the apical constriction, which is usually located short of the radiographic apex. Working to or beyond the radiographic apex increases extrusion and over-instrumentation.

15. Question 15Vital Pulp Therapy, Regenerative Endodontics and Pharmacologymedium

    A healthy adult has symptomatic irreversible pulpitis with symptomatic apical periodontitis, no swelling and no fever. What is the most appropriate management?

    1. APrescribe amoxicillin and delay treatment
    2. BPrescribe amoxicillin with pulpectomy
    3. CPulpectomy with analgesics, no antibiotics
    4. DPrescribe clindamycin only
    Show answer and explanation▾

    Answer: C. Pulpectomy with analgesics, no antibiotics

    Antibiotics are not recommended for irreversible pulpitis or apical periodontitis without systemic involvement or spreading infection; definitive treatment such as pulpectomy with analgesics is appropriate. Antibiotic use here adds adverse effects and resistance without benefit.

Last reviewed September 2026. Questions are original and written to the published exam blueprint; they are not taken from any real paper.