Third Molar Flap Design — MFDS Part 1 MCQ

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ModerateOral Surgery PrinciplesThird Molar Flap DesignMFDS Part 1

During surgical removal of an impacted mandibular third molar, the incision extends forwards from the anterior border of the ramus, continues through the gingival sulcus around the mandibular second molar, and includes one buccal releasing incision extending into the vestibule. Which flap design is described?

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Correct answer: A — Triangular buccal flap with one releasing incision

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

A is correct. A triangular buccal mucoperiosteal flap used in mandibular third-molar surgery combines the distal and sulcular incision with a single buccal releasing incision. The release increases flap mobility and surgical access while the flap retains a broad vascular base. An envelope flap has a comparable distal and sulcular component but no vertical releasing incision, so B does not match the stem. A rectangular flap requires two releases rather than one. A lingually based flap would place reflection and incision on the lingual aspect, where the lingual nerve is at risk, and is not the design described. A semilunar incision is remote from the gingival margin and does not incorporate the stated sulcular incision. Neither triangular nor envelope flaps are universally preferred; selection depends on access and the individual case.

Reference: Lopes da Silva BC, Machado GF, Primo Miranda EF, Galvão EL, Falci SGM. Envelope or triangular flap for surgical removal of third molars? A systematic review and meta-analysis. British Journal of Oral and Maxillofacial Surgery, 2020. https://pubmed.ncbi.nlm.nih.gov/31974006/