Gutta-Percha Composition — MFDS Part 1 MCQ

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HardDental MaterialsGutta-Percha CompositionMFDS Part 1

In conventional commercially available endodontic gutta-percha points, which constituent–role pairing identifies the component that usually forms the largest proportion by mass?

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Correct answer: B — Zinc oxide — inorganic filler

The correct answer is **A: zinc oxide — inorganic filler**. Although the material is named after its gutta-percha polymer, conventional endodontic points contain substantially more zinc oxide by mass. Analytical studies have reported approximately 66–84% zinc oxide, compared with roughly 15–20% gutta-percha polymer, although formulations vary between manufacturers. The trans-1,4-polyisoprene gutta-percha component forms the continuous polymeric matrix but is not the largest mass fraction. Barium sulfate or another heavy-metal sulfate provides radiopacity and is present in a smaller proportion. Waxes and resins act as plasticisers and processing aids and constitute only a minor fraction. Pigments such as titanium dioxide do not form the bulk of conventional points.

Reference: Gurgel-Filho ED et al. Chemical and X-ray analyses of five brands of dental gutta-percha cone. International Endodontic Journal. 2003;36:302–307. https://pubmed.ncbi.nlm.nih.gov/12702126/