Endodontics · single question
The Law of Concentricity states that the walls of the pulp chamber are concentric with the external tooth surface at which level?
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Correct answer: D. Cementoenamel junction (CEJ)
- A. Incorrect. The height of contour is the widest point of the crown — this is relevant to crown form but not specifically the Law of Concentricity.
- B. Incorrect. The middle of the pulp is not the specific level referenced in the Law of Concentricity.
- C. Incorrect. At the root apex, canal anatomy varies considerably and is not uniformly concentric with the external root surface.
- D. Correct. The LAW OF CONCENTRICITY states that the walls of the pulp chamber are concentric with the external surface of the tooth at the LEVEL OF THE CEJ. This principle is used during endodontic access preparation — the outline form of the access cavity should be shaped concentrically with the external tooth outline as seen at the CEJ level, helping avoid perforation.