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ABOI/ID practice questions

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Question 1Diagnosis

Which radiographic appearance is most characteristic of a periapical cyst compared with a periapical granuloma?

  1. A well-defined radiolucency with a corticated border and a diameter typically greater than 1 cm Correct answer.
  2. A diffuse radiolucency with ill-defined margins and no cortical rim
  3. A generalized widening of the periodontal ligament space with loss of the lamina dura
  4. A mixed radiolucent-radiopaque lesion centered on the crown of an unerupted tooth

Explanation

Peripheral giant cell granuloma and periapical cysts are distinguished from granulomas histologically, but radiographically a cyst tends to be larger (>1 cm), more rounded, and bounded by a sclerotic/corticated margin. Granulomas are more often ill-defined and smaller. Definitive distinction still requires histopathology.

Question 2Diagnosis

A patient reports sharp, fleeting pain lasting seconds triggered by cold liquids that resolves immediately after the stimulus is removed. This best indicates:

  1. Symptomatic apical periodontitis
  2. Irreversible pulpitis
  3. Necrotic pulp
  4. Reversible pulpitis Correct answer.

Explanation

Reversible pulpitis produces sharp pain provoked by thermal stimuli that subsides promptly once the stimulus is removed, with no spontaneous pain. Irreversible pulpitis typically causes lingering or spontaneous pain.

Question 3Diagnosis

In the cold test, a response that lingers for more than 30 seconds after removal of the stimulus most strongly suggests:

  1. Calcific metamorphosis
  2. Normal pulp
  3. Irreversible pulpitis Correct answer.
  4. Reversible pulpitis

Explanation

A prolonged, lingering response to cold indicates irreversible pulpitis, reflecting an inflamed pulp unable to return to baseline. Normal and reversible pulps respond briefly and resolve quickly.

Question 4Diagnosis

Which pulp sensibility test is generally considered the most reliable for detecting vital pulp in teeth with extensive restorations?

  1. Electric pulp test
  2. Cold test with refrigerant spray Correct answer.
  3. Percussion test
  4. Transillumination

Explanation

Cold testing with a refrigerant spray is highly reliable for confirming pulp vitality because it directly stimulates A-delta fibers, and it is less subject to false positives than the electric pulp test. The EPT can be affected by restorations, contact with adjacent teeth, and patient anxiety.

Question 5Diagnosis

A tooth is unresponsive to cold and EPT, is asymptomatic, and shows a normal periapical radiograph with a history of trauma 10 years ago. The most likely diagnosis is:

  1. Normal pulp
  2. Asymptomatic apical periodontitis
  3. Reversible pulpitis
  4. Pulp necrosis Correct answer.

Explanation

Loss of response to sensibility testing with no periapical pathosis and a remote trauma history is consistent with pulp necrosis (or calcific obliteration). Necrosis is defined by absence of vitality, not by periapical changes.

Question 6Diagnosis

The most appropriate initial diagnostic test to differentiate symptomatic apical periodontitis from a cracked tooth in a posterior tooth is:

  1. Cone-beam computed tomography
  2. Radiographic bone sounding
  3. Percussion and bite tests Correct answer.
  4. Pulp sensibility testing

Explanation

Percussion and the bite test (Tooth Slooth) help localize pain to the periapex or to a crack line. A cracked tooth often elicits pain on release of biting, while apical periodontitis produces pain on percussion.

Question 7Diagnosis

Which clinical finding most strongly supports a diagnosis of irreversible pulpitis rather than symptomatic apical periodontitis?

  1. Pain on percussion of the tooth
  2. Spontaneous, lingering pain relieved by cold stimulus Correct answer.
  3. Widened PDL space on radiograph
  4. Pain localized to the periapex with a sinus tract

Explanation

Irreversible pulpitis is characterized by spontaneous or lingering pain, often provoked by thermal stimuli. Apical periodontitis produces pain on biting or percussion and periapical radiographic changes.

Question 8Diagnosis

A localized swelling that is soft, fluctuant, and painful, with a vital pulp and no periapical radiolucency, most likely represents:

  1. Acute apical abscess Correct answer.
  2. Periodontal abscess
  3. Chronic apical abscess
  4. Phoenix abscess

Explanation

An acute apical abscess presents with rapid onset of pain and swelling, often before radiographic changes appear, and the pulp may still be partially vital early in the process. A phoenix abscess arises from a pre-existing chronic lesion.

Question 9Diagnosis

The term 'phoenix abscess' refers to:

  1. A cyst that develops from a granuloma
  2. An abscess associated with a vertical root fracture
  3. An acute exacerbation of a chronic periapical lesion Correct answer.
  4. A sinus tract draining through the gingival sulcus

Explanation

A phoenix abscess is an acute exacerbation of an existing chronic apical periodontitis lesion, often after incomplete treatment or a change in host resistance. It presents with acute symptoms superimposed on a pre-existing radiolucency.

Question 10Diagnosis

Which radiographic feature best distinguishes a lateral periodontal cyst from a periapical lesion?

  1. Presence of a corticated border
  2. Association with the apex of a nonvital tooth
  3. Association with an impacted tooth
  4. Location along the lateral root surface of a vital tooth Correct answer.

Explanation

A lateral periodontal cyst occurs along the lateral aspect of a vital tooth, typically in the mandibular premolar-canine region. Periapical lesions are centered on the apex of a nonvital tooth.

Question 11Diagnosis

A patient presents with a draining sinus tract on the buccal gingiva. The most appropriate first step in diagnosis is:

  1. Referral for a gingival biopsy
  2. Immediate extraction of the suspected tooth
  3. Placement of a gutta-percha cone in the tract and radiographing to trace its origin Correct answer.
  4. Prescription of antibiotics without further evaluation

Explanation

Tracing the sinus tract with a gutta-percha cone followed by radiography identifies the source tooth. This is a standard diagnostic maneuver before definitive treatment.

Question 12Diagnosis

In pulp sensibility testing, a false-positive response to the electric pulp test is most likely caused by:

  1. Conduction of current to adjacent teeth or gingiva Correct answer.
  2. Complete pulp necrosis
  3. Calcific obliteration of the canal
  4. Recent administration of a local anesthetic

Explanation

A false positive on EPT occurs when current spreads through restorations or saliva to adjacent teeth or gingiva, causing a response unrelated to the tested pulp. Proper isolation and placement reduce this risk.

Question 13Diagnosis

Which of the following is the most reliable indicator of pulp vitality in a recently traumatized tooth?

  1. Absence of response to cold testing on the day of injury
  2. Immediate positive response to cold testing
  3. Presence of a periapical radiolucency
  4. Serial sensibility testing over several weeks Correct answer.

Explanation

After trauma, pulp responses may be temporarily suppressed (concussion/luxation), so a single test is unreliable. Serial sensibility testing over weeks to months provides the most reliable assessment of vitality recovery or necrosis.

Question 14Diagnosis

A tooth has a history of trauma and now shows a yellowish discoloration with a diminished response to cold but no periapical radiolucency. The most likely diagnosis is:

  1. Symptomatic apical periodontitis
  2. Normal pulp
  3. Irreversible pulpitis
  4. Pulp necrosis with calcific metamorphosis Correct answer.

Explanation

Yellow discoloration, reduced sensibility, and an absence of periapical pathosis following trauma suggest calcific metamorphosis, often with partial or complete pulp necrosis. The canal appears obliterated radiographically.

Question 15Diagnosis

Which of the following best defines a 'cracked tooth syndrome' presentation?

  1. Pain only on thermal stimulation that resolves immediately
  2. Sharp pain on release of biting pressure, often with a normal pulp response Correct answer.
  3. Generalized dull ache in multiple adjacent teeth
  4. Constant throbbing pain with a sinus tract

Explanation

Cracked tooth syndrome classically produces sharp pain on release of biting (rebound pain) because the crack opens and closes under occlusal load. Pulp tests may be normal or abnormal depending on crack extent.

Question 16Diagnosis

A diffuse radiolucency with a 'ground-glass' appearance in the posterior mandible of a young adult, associated with a vital tooth, most likely represents:

  1. Radicular cyst
  2. Ameloblastoma
  3. Fibrous dysplasia Correct answer.
  4. Dentigerous cyst

Explanation

Fibrous dysplasia produces a ground-glass radiopacity/radiolucency with blending into surrounding bone and is associated with vital teeth. It is a developmental fibro-osseous lesion.

Question 17Diagnosis

Which condition is characterized by a 'soap bubble' or multilocular radiolucency in the posterior mandible of a young adult, often causing root resorption?

  1. Radicular cyst
  2. Simple bone cyst
  3. Ameloblastoma Correct answer.
  4. Odontogenic keratocyst

Explanation

Ameloblastoma classically presents as a multilocular 'soap bubble' radiolucency in the posterior mandible, often with root resorption and expansion. It is locally aggressive.

Question 18Diagnosis

A unilocular radiolucency with a scalloped border between the roots of vital mandibular premolars and no expansion most likely represents:

  1. Dentigerous cyst
  2. Simple bone cyst Correct answer.
  3. Ameloblastoma
  4. Odontogenic keratocyst

Explanation

A simple bone cyst (traumatic bone cyst) appears as a unilocular radiolucency that scallops between the roots of vital teeth, typically without expansion. It is usually an incidental finding in young patients.

Question 19Diagnosis

Which radiographic feature is most helpful in distinguishing a dentigerous cyst from an odontogenic keratocyst?

  1. Location in the posterior mandible
  2. Size greater than 2 cm
  3. Attachment to the cementoenamel junction of an unerupted tooth Correct answer.
  4. Presence of a corticated border

Explanation

A dentigerous cyst attaches at the cementoenamel junction and encloses the crown of an unerupted tooth. An odontogenic keratocyst may mimic this but often shows a more irregular attachment and growth along the bone.

Question 20Diagnosis

A patient presents with a firm, nonfluctuant swelling of the buccal vestibule adjacent to a nonvital tooth with a large periapical radiolucency. The most likely diagnosis is:

  1. Peri-implantitis
  2. Apical cyst Correct answer.
  3. Chronic apical abscess with cellulitis
  4. Acute apical abscess

Explanation

A firm, nonfluctuant swelling adjacent to a nonvital tooth with a large well-defined radiolucency suggests an apical cyst or granuloma. Cysts are typically asymptomatic unless secondarily infected.

Question 21Diagnosis

Which of the following is the most appropriate use of cone-beam computed tomography in endodontic diagnosis?

  1. Routine screening of all teeth before endodontic treatment
  2. Replacement of pulp sensibility testing
  3. Assessment of complex anatomy, suspected fractures, and periapical lesions not seen on periapical radiographs Correct answer.
  4. Detection of caries in all posterior teeth

Explanation

CBCT is indicated when conventional radiographs are inconclusive, such as complex anatomy, suspected root fractures, and subtle periapical lesions. It is not a routine screening tool because of radiation dose.

Question 22Diagnosis

A patient reports pain on biting on a tooth with a normal pulp response, a normal periapical radiograph, and pain when the tooth is released from biting. The most likely diagnosis is:

  1. Cracked tooth syndrome Correct answer.
  2. Reversible pulpitis
  3. Normal tooth
  4. Acute apical abscess

Explanation

Pain on release of biting with a normal pulp and radiograph is classic for cracked tooth syndrome. The crack opens under load and produces sharp pain on rebound.

Question 23Diagnosis

Which of the following findings most strongly suggests a vertical root fracture rather than a failed endodontic treatment?

  1. Presence of a post and core
  2. A history of previous root canal treatment
  3. A deep, narrow periodontal pocket isolated to one aspect of the root Correct answer.
  4. A diffuse periapical radiolucency

Explanation

A vertical root fracture often presents with a narrow, deep, isolated periodontal pocket along the fracture line, sometimes with a 'J-shaped' radiolucency. This differs from the typical presentation of failed endodontic treatment.

Question 24Diagnosis

Which of the following best describes the diagnostic significance of a 'halo' radiolucency around the apex of a tooth?

  1. It confirms a diagnosis of irreversible pulpitis
  2. It indicates a normal periodontal ligament
  3. It suggests a periapical inflammatory lesion Correct answer.
  4. It is pathognomonic for a dentigerous cyst

Explanation

A halo radiolucency around the apex reflects periapical inflammation (granuloma, cyst, or abscess) and indicates loss of apical bone. It is a radiographic sign, not a pulpal diagnosis.

Question 25Diagnosis

A patient with a nonvital tooth has a draining sinus tract and a large periapical radiolucency. The most likely diagnosis is:

  1. Acute apical abscess
  2. Reversible pulpitis
  3. Phoenix abscess
  4. Chronic apical abscess Correct answer.

Explanation

A chronic apical abscess is characterized by a draining sinus tract, a nonvital pulp, and a periapical radiolucency, usually with minimal symptoms. It represents a long-standing, low-grade infection.

Question 26Diagnosis

Which pulp sensibility test relies on the hydrodynamic movement of fluid within dentinal tubules to stimulate intradental nerve endings?

  1. Electric pulp test
  2. Cold thermal test Correct answer.
  3. Transillumination test
  4. Selective anesthesia test

Explanation

Cold testing provokes a response through hydrodynamic fluid movement in dentinal tubules that activates A-delta nerve fibers, producing a sharp, transient sensation in a vital pulp. The other modalities do not depend on this mechanism, and transillumination assesses structural integrity rather than innervation.

Question 27Diagnosis

A patient reports a sharp, fleeting pain to cold that resolves immediately after the stimulus is removed, with no spontaneous pain. This response is most consistent with which pulpal diagnosis?

  1. Necrotic pulp
  2. Previously treated pulp
  3. Reversible pulpitis Correct answer.
  4. Irreversible pulpitis

Explanation

Reversible pulpitis produces a provoked, sharp response that subsides promptly once the stimulus is withdrawn, and the pulp retains healing capacity. Irreversible pulpitis typically yields lingering pain, and a necrotic or previously treated pulp would not respond to cold.

Question 28Diagnosis

Which clinical test is most useful for distinguishing pain of pulpal origin from pain of periodontal origin?

  1. Percussion and palpation Correct answer.
  2. Radiographic bone level assessment
  3. Caries excavation
  4. Cold thermal testing

Explanation

Percussion and palpation assess the periodontal attachment and periapical tissues, so tenderness to these tests localizes pain to the periodontium. Thermal testing evaluates pulp sensibility, and radiographic bone levels do not reproduce the patient's pain.

Question 29Diagnosis

A localized, raised, fluid-filled lesion on the gingiva adjacent to a nonvital tooth that collapses when drained is best described as which finding?

  1. Fibroma
  2. Mucocele
  3. Ranula
  4. Parulis Correct answer.

Explanation

A parulis is a localized gingival abscess swelling that arises from a draining endodontic infection and typically collapses when drained. A mucocele and ranula are salivary gland lesions, and a fibroma is a firm, nonfluctuant connective tissue mass.

Question 30Diagnosis

A patient reports spontaneous, poorly localized throbbing pain that wakes them at night and lingers after cold stimulus removal. The most likely diagnosis is:

  1. Reversible pulpitis
  2. Symptomatic apical periodontitis
  3. Normal pulp
  4. Irreversible pulpitis Correct answer.

Explanation

Spontaneous, lingering, nocturnal pain that is poorly localized reflects irreversible pulpitis with pulpal inflammation that cannot resolve. Reversible pulpitis produces only provoked, transient pain, and symptomatic apical periodontitis presents primarily as pain to biting and percussion.

Question 31Diagnosis

Which diagnostic finding is most indicative of a necrotic pulp?

  1. A positive response to the electric pulp test
  2. A lingering painful response to cold
  3. No response to cold or electric pulp testing with a periapical radiolucency Correct answer.
  4. Sharp pain that resolves immediately on stimulus removal

Explanation

A pulp that fails to respond to both thermal and electric sensibility testing, together with periapical changes, indicates necrosis. Lingering or sharp provoked responses indicate vital, inflamed pulp tissue.

Question 32Diagnosis

Which of the following is the most appropriate purpose of a diagnostic anesthesia test in endodontic diagnosis?

  1. To measure the width of the periodontal ligament space
  2. To assess the degree of tooth mobility
  3. To localize the source of pain when sensibility and percussion tests are inconclusive Correct answer.
  4. To determine the depth of caries

Explanation

Selective anesthesia helps localize the responsible tooth or quadrant when the patient cannot identify the source of pain and other tests are equivocal. It does not measure caries depth, ligament width, or mobility.

Question 33Diagnosis

A patient has a nonvital tooth with a periapical radiolucency and a sinus tract that traces to the apex. Which diagnosis best fits this presentation?

  1. Periapical granuloma without infection
  2. Phoenix abscess
  3. Chronic apical abscess Correct answer.
  4. Acute apical abscess

Explanation

A chronic apical abscess is characterized by a draining sinus tract with a nonvital pulp and periapical radiolucency, and it is typically asymptomatic because the tract provides drainage. An acute or phoenix abscess presents with severe pain and swelling without a draining tract.

Question 34Diagnosis

A patient reports pain to biting on a specific tooth, and the tooth is tender to percussion with a normal response to cold. Which diagnosis is most likely?

  1. Irreversible pulpitis
  2. Normal pulp
  3. Symptomatic apical periodontitis Correct answer.
  4. Reversible pulpitis

Explanation

Symptomatic apical periodontitis produces pain to biting and tenderness to percussion, and the pulp may still test normal if inflammation is confined to the periapex. Irreversible and reversible pulpitis present primarily with thermal symptoms rather than biting pain.

Question 35Diagnosis

Which finding most strongly suggests a vertical root fracture in an endodontically treated tooth?

  1. A widened periodontal ligament space at the apex only
  2. A narrow radiolucent line along the root with a deep, narrow periodontal pocket Correct answer.
  3. A diffuse coronal radiolucency under a restoration
  4. A large periapical radiolucency with a sclerotic border

Explanation

A vertical root fracture typically produces a narrow radiolucent line along the root together with a deep, narrow, isolated periodontal pocket. A periapical radiolucency or apical ligament widening alone is nonspecific and can occur with ordinary endodontic failure.

Question 36Diagnosis

Which radiographic feature most helps distinguish a radicular cyst from a periapical granuloma?

  1. A corticated border with a round shape and larger size Correct answer.
  2. Presence of a lamina dura along the root
  3. Loss of the lamina dura
  4. Widening of the periodontal ligament space

Explanation

A radicular cyst tends to be round with a well-defined, corticated border and is often larger than a granuloma. Loss of lamina dura and ligament widening are early periapical changes seen with both lesions and are not discriminatory.

Question 37Diagnosis

A patient reports pain that is difficult to localize to a specific tooth and increases when bending over. Which diagnosis is most consistent with this presentation?

  1. Normal pulp
  2. Symptomatic apical periodontitis Correct answer.
  3. Attrition
  4. Reversible pulpitis

Explanation

Symptomatic apical periodontitis can produce poorly localized pain that worsens with postural change because of pressure changes in the inflamed periapical tissues. Reversible pulpitis is provoked and localized, and attrition is generally asymptomatic.

Question 38Diagnosis

Which clinical test best differentiates a sinus tract of endodontic origin from one of periodontal origin?

  1. Percussion testing alone
  2. Measuring probing depth on the adjacent teeth only
  3. Cold thermal testing alone
  4. Tracing the sinus tract with a gutta-percha cone and radiographing it Correct answer.

Explanation

Tracing the sinus tract with a radiopaque cone and radiographing it identifies the source, with an endodontic tract typically leading to a periapical lesion. Percussion or thermal tests alone may not localize the tract's origin, and probing depths alone do not reveal the internal source.

Question 39Diagnosis

A patient has a firm, bony-hard swelling of the anterior maxilla with a nonvital incisor and a periapical radiolucency. Which diagnosis is most likely?

  1. Normal pulp
  2. Reversible pulpitis
  3. Acute apical abscess with fluctuance
  4. Chronic apical abscess with a bony-hard swelling Correct answer.

Explanation

A firm, bony-hard swelling adjacent to a nonvital tooth with a periapical radiolucency suggests a chronic process with a draining or contained infection. A fluctuant swelling would indicate an acute abscess with pus formation, and reversible pulpitis or normal pulp would not produce a swelling.

Question 40Diagnosis

Which radiographic finding is most suggestive of external root resorption rather than internal resorption?

  1. A diffuse widening of the apical periodontal ligament
  2. A radiolucency centered on the canal space
  3. A periapical radiolucency with a sclerotic border
  4. A radiolucency that changes position relative to the root canal on different angulations Correct answer.

Explanation

External resorption is located on the root surface, so its relationship to the canal changes with different radiographic angulations, whereas internal resorption remains centered on the canal. Apical ligament widening and periapical radiolucency are unrelated to resorption type.

Question 41Diagnosis

Which finding is most useful in distinguishing a lateral periodontal cyst from an inflammatory periapical lesion?

  1. A diffuse radiolucency with loss of lamina dura
  2. A vital pulp with a well-defined radiolucency between the roots Correct answer.
  3. A nonvital pulp with a periapical radiolucency
  4. A widened periodontal ligament space

Explanation

A lateral periodontal cyst occurs adjacent to a vital tooth as a well-defined radiolucency between the roots, whereas inflammatory periapical lesions arise from a nonvital pulp. Diffuse radiolucency and ligament widening are nonspecific inflammatory signs.

Question 42Diagnosis

A patient has a history of trauma to a maxillary incisor with a yellowish crown discoloration and no response to cold, but no periapical radiolucency. Which diagnosis is most likely?

  1. Normal pulp
  2. Symptomatic apical periodontitis
  3. Reversible pulpitis
  4. Pulp necrosis Correct answer.

Explanation

A yellowish discoloration with no response to sensibility testing and no periapical change suggests pulp necrosis following trauma. Reversible pulpitis and normal pulp would respond to cold, and symptomatic apical periodontitis would show percussion tenderness and periapical change.

Question 43Diagnosis

A patient reports pain on chewing that is relieved by clenching the teeth together. Which diagnosis is most consistent with this presentation?

  1. Irreversible pulpitis
  2. Cracked tooth syndrome Correct answer.
  3. Reversible pulpitis
  4. Normal pulp

Explanation

Cracked tooth syndrome characteristically causes pain on release of biting pressure, and the pain may be relieved by clenching because the crack is splinted. Irreversible and reversible pulpitis present with thermal symptoms rather than bite-related pain.

Question 44Diagnosis

Which of the following is the most reliable way to determine whether a periapical radiolucency is associated with a vital or nonvital pulp?

  1. Measuring the size of the radiolucency
  2. Assessing the presence of a sclerotic border
  3. Pulp sensibility testing of the tooth Correct answer.
  4. Evaluating the periodontal ligament width

Explanation

Pulp sensibility testing determines whether the pulp is vital and innervated, which is essential to correlate a radiolucency with pulpal status. The size, border, and ligament width describe the lesion but do not establish pulp vitality.

Question 45Diagnosis

A patient presents with a diffuse, nonfluctuant swelling of the buccal vestibule adjacent to a nonvital tooth with a large periapical radiolucency and no sinus tract. Which diagnosis is most likely?

  1. Chronic apical abscess
  2. Phoenix abscess
  3. Acute apical abscess Correct answer.
  4. Normal pulp

Explanation

A diffuse, nonfluctuant swelling with a nonvital tooth and periapical radiolucency without a sinus tract suggests an acute apical abscess in which pus is contained within the tissues. A chronic apical abscess would have a draining tract, and a phoenix abscess arises from acute exacerbation of a chronic lesion with severe symptoms.

Question 46Diagnosis

Which clinical finding most strongly suggests a vertical root fracture rather than a failed endodontic treatment?

  1. A diffuse coronal radiolucency under a restoration
  2. A widened periodontal ligament space at the apex only
  3. A large periapical radiolucency with a sclerotic border
  4. A narrow radiolucent line along the root with a deep, narrow periodontal pocket Correct answer.

Explanation

A vertical root fracture typically produces a narrow radiolucent line along the root together with a deep, narrow, isolated periodontal pocket. A periapical radiolucency or apical ligament widening alone is nonspecific and can occur with ordinary endodontic failure.

Question 47Diagnosis

A patient describes a transient, mild ache in a mandibular molar that occurs only after drinking a cold beverage and disappears within seconds after the stimulus is removed. The tooth responds to cold with a brief, sharp sensation, and the response subsides immediately. Which pulp diagnosis is most consistent with these findings?

  1. Necrosis
  2. Reversible pulpitis Correct answer.
  3. Irreversible pulpitis
  4. Previously treated

Explanation

Reversible pulpitis is characterized by provoked pain that is mild and resolves promptly after removal of the stimulus, indicating the pulp is still vital and capable of healing. Irreversible pulpitis typically produces spontaneous or lingering pain, while necrosis and previously treated teeth do not respond to thermal stimuli.

Question 48Diagnosis

A patient presents with a draining sinus tract on the buccal gingiva of a mandibular premolar. The tooth is nonvital, and a periapical radiolucency is present. To confirm that the sinus tract originates from the endodontic infection rather than from a periodontal pocket, which technique is most appropriate?

  1. Take a bitewing radiograph to assess the alveolar crest
  2. Probe the periodontal pocket depths around the tooth
  3. Trace the sinus tract with a gutta-percha cone and take a radiograph Correct answer.
  4. Perform a pulp vitality test with cold refrigerant

Explanation

Tracing the sinus tract with a radiopaque material such as gutta-percha and taking a radiograph helps delineate the origin of the tract. If the tract traces to the apex, it is likely of endodontic origin; if it traces to the lateral aspect or furcation, a periodontal origin is more likely.

Question 49Diagnosis

A patient has a history of trauma to a maxillary central incisor. The tooth is discolored yellow, does not respond to cold or electric pulp testing, and has a periapical radiolucency. Which additional finding would most strongly indicate that the pulp is necrotic rather than simply nonresponsive due to trauma?

  1. Negative response to percussion
  2. History of orthodontic movement
  3. Radiographic widening of the periodontal ligament space
  4. Presence of a sinus tract Correct answer.

Explanation

A sinus tract indicates chronic infection and necrosis, confirming that the pulp is nonvital and infected. While a widened PDL may be seen in trauma, it is not specific for necrosis; a sinus tract is a definitive sign of pulp necrosis with infection.

Question 50Diagnosis

A patient reports a dull, aching pain in the maxillary anterior region that is difficult to localize. The pain is exacerbated by bending over or lying down. Clinical examination reveals a nonvital maxillary lateral incisor with a periapical radiolucency. Which diagnosis best explains the patient's symptoms?

  1. Acute apical abscess
  2. Symptomatic apical periodontitis Correct answer.
  3. Phoenix abscess
  4. Chronic apical abscess

Explanation

Symptomatic apical periodontitis presents with pain on biting and pressure, but the pain is typically localized. However, the positional exacerbation (bending over, lying down) and difficulty localizing suggest a fluid-filled lesion under pressure, which is more characteristic of an acute apical abscess. Among the options, symptomatic apical periodontitis is the best fit because it involves inflammation of the periapical tissues with pain, but without pus formation or swelling.