MCQs in Internal Anatomy of the Pulp System
Internal Anatomy of the Pulp System Lecture
Section 1: General Concepts
1. Lack of knowledge about pulp morphology is considered the ______ most common cause of treatment failure in endodontics.
a) First
b) Second
c) Third
d) Fourth
2. The first most common cause of treatment failure in endodontics is related to:
a) Diagnostic and treatment planning errors
b) Access cavity errors
c) Instrument separation
d) Perforation
3. A key principle of pulp anatomy states that the pulp system:
a) Is unrelated to tooth shape
b) Mirrors the external tooth shape
c) Always remains round in cross-section
d) Is uniform across all patients
4. Which of the following is rarely perfectly round in anatomy?
a) Root outline
b) Pulp horns
c) Root canal
d) Apical foramen
5. A single root may show different cross-sectional shapes at:
a) Only the cervical third
b) Only the apical third
c) Cervical, middle, and apical thirds
d) Only the middle third
Section 2: Methods for Determining Pulp Anatomy
6. Textbooks are considered the most reliable source for:
a) Radiographic anomalies
b) Baseline pulp anatomy and variations
c) Surgical exploration
d) Patient-specific changes
7. Which factor is not typically memorized from textbook knowledge for pulp anatomy?
a) Number of roots
b) Number of canals
c) Patient ethnicity
d) Cross-sectional shapes
8. Conventional periapical radiographs are limited because they provide:
a) Only two dimensions
b) Clear 3D imaging
c) Full visualization of irregularities
d) A cross-sectional view
9. Radiographs often show canals as uniform and tapered, but in reality they may be:
a) Always straight
b) Irregular in shape
c) Absent
d) Obstructed
10. Special radiographic techniques such as angled views are especially useful to detect:
a) Coronal pulp horns
b) Missed canals and curvatures
c) CEJ level
d) Secondary dentin
11. Exploration during treatment primarily occurs during:
a) Diagnostic imaging
b) Access cavity preparation and canal exploration
c) Crown cutting
d) Extraction
12. Even with exploration, canals may remain:
a) Easily visible
b) Straight
c) Hidden or difficult to locate
d) Obliterated in all cases
Section 3: Canal Morphology and Variations
13. The standard classification of root canal configurations was given by:
a) Weine
b) Vertucci
c) Krasner
d) Rankow
14. Vertucci described how many canal configurations?
a) 6
b) 8
c) 10
d) 12
15. Ethnicity influences canal variations. Which group has more frequent extra canals in mandibular premolars?
a) Caucasians
b) African-Americans
c) Asians
d) Europeans
16. Approximately what percentage of mandibular first premolars in African-American patients show extra canals?
a) 5%
b) 14%
c) 33%
d) 50%
17. In Caucasians, extra canals in mandibular second premolars are found in about:
a) 8%
b) 33%
c) 3%
d) 20%
Section 4: Identification of Canals and Orifices
18. The rule of thumb in endodontics is to assume the presence of:
a) One canal
b) Two canals until proven otherwise
c) Three canals
d) Four canals
19. Maxillary anterior roots usually contain:
a) Two canals
b) A single canal
c) Three canals
d) Four canals
20. Which maxillary root rarely contains two canals?
a) Palatal
b) Distobuccal and lingual roots of molars
c) Mesiobuccal
d) Premolars
Section 5: Laws of Canal Orifice Location (Krasner & Rankow)
21. According to Symmetry Law 1, canal orifices are:
a) Equidistant from a mesiodistal line across the chamber floor
b) Asymmetric
c) Randomly placed
d) Closer to the buccal wall
22. Symmetry Law 1 has an exception in which teeth?
a) Maxillary molars
b) Mandibular incisors
c) Premolars
d) Canines
23. The Color Change Law states that:
a) Chamber floor is lighter than walls
b) Chamber floor is darker than surrounding walls
c) Both are the same color
d) It has no diagnostic value
Section 6: Components of the Pulp System
24. The pulp chamber represents the:
a) Radicular portion
b) Coronal portion
c) Apical portion
d) Lateral canals
25. The radicular portion of the pulp system is called the:
a) Chamber
b) Horn
c) Root canal
d) Foramen
26. Which of the following is not a component of the pulp cavity?
a) Pulp horns
b) Canal orifices
c) Cementum layer
d) Accessory canals
Section 7: Pulp Horns and Chamber
27. In posterior teeth, pulp horns are typically:
a) Absent
b) One per cusp
c) Only mesial
d) Only distal
28. In incisors, pulp horns are usually:
a) Three
b) None
c) Mesial and distal
d) One per cusp
29. With age, pulp horns move closer to:
a) Cusp tip
b) Chamber floor
c) Cervical margin
d) Apical constriction
30. The roof of the pulp chamber in mature molars lies at the level of the:
a) Dentin-enamel junction
b) Cementoenamel junction (CEJ)
c) Root apex
d) Alveolar crest
Section 8: Root Canals
31. Most root canals are curved, often in which plane?
a) Mesiodistal
b) Faciolingual
c) Horizontal
d) Apico-occlusal
32. Curvatures are often invisible on:
a) Textbooks
b) Radiographs
c) Access preparation
d) Microscopy
33. Assuming a canal is straight may result in:
a) Underfilling
b) Over-enlargement, ledging, or perforation
c) Apex formation
d) Easier obturation
Section 9: Accessory Canals
34. Accessory canals commonly occur in which region?
a) Middle third
b) Coronal third
c) Apical third
d) CEJ
35. The clinical significance of accessory canals is that they:
a) Allow passage of irritants to the periodontium
b) Always require obturation
c) Are essential for success
d) Do not contain any tissue
36. Which statement is true about accessory canals?
a) Always cleaned effectively
b) Rarely cleaned or shaped completely
c) Always round in shape
d) Absent in posterior teeth
Internal Anatomy of the Pulp System Lecture
Section 10: Apical Region
37. In young teeth, the apex is usually:
a) Relatively straight
b) Curved distally
c) Obliterated
d) Ribbon-shaped
38. With aging, the apex tends to curve:
a) Mesially
b) Distally
c) Buccally
d) Palatally
39. The apical foramen usually lies:
a) Exactly at anatomic apex
b) Slightly offset (0.5–1 mm) from anatomic apex
c) At CEJ
d) At chamber floor
40. In immature teeth, the apical foramen is:
a) Closed
b) Wide open
c) Absent
d) Obliterated
41. The apical constriction is defined by:
a) Radiographs
b) Apex locators
c) Not reliably defined by cementodentinal junction
d) Surgical access
42. Apical anatomy is often complex and may include:
a) Round uniform canals
b) Deltas, ramifications, and oval canals
c) Perfectly straight canals
d) Single passage only
Section 11: Clinical Application
43. Failure to detect an additional canal, such as MB2 in maxillary molars, may result in:
a) Faster healing
b) Persistent symptoms and failure
c) Easier obturation
d) No consequence
44. In clinical practice, location of canal orifices is guided by:
a) Cementum thickness
b) Patient history
c) Floor-wall junction and developmental lines
d) CEJ color
Section 12: Special Notes
45. Secondary dentin formation affects pulp anatomy by:
a) Enlarging canals
b) Reducing pulp space and shifting horns
c) Straightening roots
d) Eliminating apical constriction
46. Irregularities like fins and isthmuses are more common in:
a) Anterior teeth
b) Posterior teeth
c) Premolars only
d) Incisors
47. These irregularities are difficult to:
a) Access and obturate completely
b) Visualize in textbooks
c) Detect by radiographs
d) Bypass with irrigation
Section 13: Variations of Root and Pulp Anatomy
48. Unusual root or pulp morphology tends to be:
a) Unilateral
b) Bilateral
c) Random
d) Only in posterior teeth
49. Dens invaginatus is most commonly found in:
a) Mandibular premolars
b) Maxillary lateral incisors
c) Maxillary canines
d) Mandibular molars
50. Dens invaginatus results from:
a) Cementum hyperplasia
b) Infolding of the enamel organ during proliferation
c) External resorption
d) Pulpal necrosis
51. A lingual pit on maxillary anterior teeth may represent a minor form of:
a) Dens invaginatus
b) Dens evaginatus
c) Dilaceration
d) Taurodontism
52. Dens evaginatus is most commonly seen in:
a) Maxillary molars
b) Maxillary incisors
c) Mandibular premolars
d) Maxillary canines
53. Which populations show a higher prevalence of dens evaginatus?
a) Europeans
b) Middle Eastern populations
c) Asians, Native Americans, and Hispanics
d) Africans
54. The small tubercle seen in dens evaginatus often contains:
a) Enamel only
b) Dentin only
c) An extension of the pulp
d) No tissues
55. When a tubercle in dens evaginatus fractures, the pulp:
a) Remains unaffected
b) Becomes exposed and necrotic
c) Always calcifies
d) Develops cysts
Section 14: Other Variations
56. High pulp horns are most commonly seen in:
a) Maxillary canines
b) Mandibular incisors
c) Mesiobuccal cusp of first molars
d) Premolars
57. A lingual groove defect is usually associated with:
a) Maxillary canines
b) Maxillary lateral incisors
c) Mandibular premolars
d) Maxillary molars
58. Lingual grooves often lead to:
a) Caries only
b) Crown fracture
c) Endodontic-periodontal lesions
d) Dilaceration
59. Dilaceration is best defined as:
a) A supernumerary root
b) A severe or complex root curvature
c) A pulp calcification
d) A fractured apex
60. The C-shaped canal configuration is most commonly found in:
a) Maxillary lateral incisors
b) Maxillary first premolars
c) Mandibular second molars
d) Mandibular canines