Endodontics · patient case question
Which is a defining feature of correct endodontic access preparation?
Patient case: The tooth that bled during shaping
demo: 38-year-old male
chief: Referred for root canal treatment of a mandibular molar with a necrotic pulp.
history: Unremarkable. No allergies.
meds: None.
findings: Tooth 19 fails to respond to cold and is tender to percussion. Access is completed and the canals are irrigated. Partway through cleaning and shaping the patient reports sudden severe pain and the operator notices brisk bleeding from the canal along with rapid swelling of the cheek. Separately, tooth 4 in the same patient shows a narrow radiolucency running along the lateral root surface and joining an apical radiolucency.
Show answer and explanation
Correct answer: B. Straight-line access to the canal orifices
- A. The floor is preserved carefully. Its developmental grooves and colour change guide the operator to the orifices, and cutting into it risks a furcal perforation.
- B. Correct. Straight-line access lets instruments reach the apical third without deflection, which prevents ledging, transportation and instrument separation. The outline should be conservative but unrestricted along the path the file must travel.
- C. The roof must be removed entirely. Any overhanging roof retains pulp tissue that discolours the crown and shelters bacteria, and it obscures orifices.
- D. Over-extension needlessly weakens the tooth. Access should be as small as possible while still permitting unimpeded instrumentation.
Note: Both removing the entire roof and achieving straight-line access are correct requirements; the recall listed them as competing options. Straight-line access is the broader principle that governs the shape of the whole preparation.