PDL Proprioception Fibres — MFDS Part 1 MCQ

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ModeratePhysiologyPDL Proprioception FibresMFDS Part 1

Which nerve fibre class principally carries low-threshold mechanoreceptive information from periodontal ligament receptors used for the fine control of tooth loading during mastication?

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Correct answer: E — A-beta fibres

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

A is correct. Periodontal mechanoreceptors that encode small tooth loads and contribute to fine masticatory control principally signal through rapidly conducting, myelinated A-beta afferents. Human recordings show that these receptors provide slowly adapting information about the magnitude and direction of tooth loading. A-delta and C fibres are predominantly associated with nociceptive and thermal signalling, although some experimental periodontal A-delta mechanosensitive units have been reported; they are not the principal low-threshold discriminative pathway tested here. B fibres are small myelinated preganglionic autonomic fibres. A-alpha fibres carry very rapidly conducting proprioceptive input principally from skeletal-muscle spindles and Golgi tendon organs rather than periodontal mechanoreceptors.

Reference: Functional maturation of periodontal mechanoreceptors during development in rats, Results, 2002. https://pubmed.ncbi.nlm.nih.gov/12480146/