skip to main content

MTA Apical Plug — MFDS Part 1 MCQ

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

ModerateRestorative PrinciplesMTA Apical PlugMFDS Part 1

A 10-year-old child has a traumatised permanent maxillary central incisor with a confirmed necrotic pulp. The radiograph shows thin, divergent root canal walls, an open apex and apical periodontitis. Following canal disinfection, a short plug of mineral trioxide aggregate is placed at the root end before obturation of the remaining canal. What is the principal purpose of this MTA apical plug?

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

Reveal the answer and explanation

Correct answer: A — To create an apical barrier that permits obturation of the immature tooth

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

The MTA apical plug creates an artificial apical barrier in a necrotic immature permanent tooth with an open apex, allowing controlled obturation of the remaining canal; this is an apexification technique. Apexogenesis (B) requires preservation of vital radicular pulp. In a regenerative endodontic procedure (C), bleeding or another scaffold is induced to encourage further root maturation, with hydraulic calcium silicate cement generally used more coronally rather than as an apical plug. Direct pulp capping (D) is treatment of a vital exposed pulp. MTA can also repair perforations (E), but the stem describes no perforation. Unlike regenerative treatment, conventional MTA apexification does not aim to produce continued root lengthening or substantial thickening of the thin dentinal walls.

Reference: Wikström A et al. Outcomes of apexification in immature traumatised necrotic teeth and risk factors for premature tooth loss: A 20-year longitudinal study. Dental Traumatology. 2024;40(6):658-671. https://pubmed.ncbi.nlm.nih.gov/38840386/