skip to main content

Fixed Prosthesis Design — ORE Part 1 MCQ

Instant feedback + full explanation. One question, done properly.

ModerateProsthodonticsFixed Prosthesis DesignORE Part 1

A 60-year-old patient requires a conventional fixed-fixed bridge to replace the lower right first molar. The lower right second premolar and second molar are planned as abutments. The second premolar has a moderate MOD restoration and the second molar has an existing full-coverage crown. According to Ante's law, which design requirement applies?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: A — The abutments should provide root surface area at least equal to that of the replaced tooth

Explanation lettering: C = shown as B · B = shown as C · E = shown as D · D = shown as E

A is correct: Ante's law states that the combined periodontal ligament (or root surface) area of the abutment teeth should equal or exceed that of the teeth replaced by pontics. Thus, the second premolar and second molar must together provide adequate supporting area for the missing first molar. B is not a definition of Ante's law; periodontal support is assessed clinically and cannot be reduced to a universal 50% threshold. C concerns span length, which may influence biomechanical loading but is unrelated to the law. D concerns preparation path of insertion and retention. E is incorrect because abutment number is determined by the proposed bridge design and prognosis, not a mandatory minimum of three. In modern treatment planning, Ante's law is a useful screening principle rather than an absolute predictor of fixed dental prosthesis survival.

Reference: Nyman S, Ericsson I. The capacity of reduced periodontal tissues to support fixed bridgework. Journal of Clinical Periodontology. 1982;9(5):409-414. https://pubmed.ncbi.nlm.nih.gov/6958689/