PDL Oblique Fibres — MFDS Part 1 MCQ

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EasyPhysiologyPDL Oblique FibresMFDS Part 1

In a healthy periodontal ligament, what is the predominant orientation of the principal fibre bundles forming the functional attachment between cementum and alveolar bone?

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Reveal the answer and explanation

Correct answer: E — Oblique to the long axis of the root

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

A is correct. The principal collagen fibre bundles of the periodontal ligament are predominantly arranged obliquely between cementum and alveolar bone. This functional alignment suspends the tooth within its socket and allows occlusal loading to be transferred through fibres acting mainly in tension. Horizontal fibres constitute a recognised but smaller group and are not present throughout the root. Fibres are not predominantly vertical and parallel to the root, randomly arranged or circumferential. Circumferential orientation may be observed locally near hard-tissue interfaces, but it does not describe the characteristic principal fibre arrangement. The original key was therefore correct, although the previous explanation used potentially confusing directional wording.

Reference: Staples R, Ivanovski S, Vaquette C, et al. Melt electrowriting scaffolds with fibre-guiding features for periodontal attachment. Acta Biomaterialia. 2024. https://pubmed.ncbi.nlm.nih.gov/38583749/