Polysulphide Properties — MFDS Part 1 MCQ
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Correct answer: E — Long working time, high tear strength, hydrophobic behaviour, and prompt pouring advisable
Explanation lettering: C = shown as A · D = shown as B · E = shown as C · B = shown as D · A = shown as E
Option A is correct. Polysulphide provides a relatively long working time and has particularly high tear strength, which helps thin sections resist tearing during removal. It is not truly hydrophilic; moisture control is therefore important. Its dimensional stability is inferior to that of addition-cured silicone because setting produces a volatile by-product, so the impression should be poured promptly. Option E is the closest distractor but is incorrect because routine delayed pouring risks dimensional change. Options B and D incorrectly assign a short working time, while C incorrectly describes polysulphide as both hydrophilic and low in tear strength.
Reference: Levartovsky S et al. Elastomeric impression materials. 2011. McConnell RJ et al. Working time of synthetic elastomeric impression material. 1994. Williams PT et al. An evaluation of the time-dependent dimensional stability of eleven elastomeric impression materials. 1984. https://pubmed.ncbi.nlm.nih.gov/21848031/