Glass Ionomer Cement — MFDS Part 1 MCQ
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Correct answer: E — Ionic bonding between polycarboxylate groups and calcium in hydroxyapatite
Conventional glass ionomer cement adheres intrinsically through chemical interaction between carboxylate groups in the polyalkenoic acid and calcium ions in the hydroxyapatite of enamel and dentine. This produces an ion-exchange layer at the tooth–cement interface, so E is correct. Micromechanical retention is not the principal mechanism for conventional glass ionomer, although surface conditioning improves wetting and some resin-modified materials may also interlock micromechanically. Glass particles do not adhere primarily through van der Waals forces. The polyacid does not form clinically significant covalent bonds with dentinal collagen, and hydrogen bonding to enamel is not the established principal mechanism.
Reference: Yoshida Y, Van Meerbeek B, Nakayama Y, et al. Evidence of chemical bonding at biomaterial-hard tissue interfaces. Journal of Dental Research. 2000;79(2):709–714. https://pubmed.ncbi.nlm.nih.gov/10728971/