Impression Decontamination — ORE Part 1 MCQ
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Correct answer: C — Rinse until visibly clean, then use a compatible immersion or bagged-spray disinfectant for the manufacturer-specified contact time
Explanation lettering: B = shown as A · D = shown as B · A = shown as C · E = shown as D · C = shown as E
A is correct. SDCEP advises immediately rinsing an impression under cold running water until saliva, blood and debris have been removed, followed by disinfection using a method compatible with the impression material. Immersion should follow the disinfectant manufacturer's instructions; spray disinfection requires containment in a plastic bag for the specified contact time. The dentist, rather than the laboratory, is responsible for decontamination before dispatch. Autoclaving and boiling are inappropriate for conventional impression materials and can cause damage or dimensional change. An alcohol wipe is not the validated immersion or contained-spray process described by SDCEP. Sending an untreated impression transfers an avoidable contamination risk to laboratory personnel.
Reference: Scottish Dental Clinical Effectiveness Programme (SDCEP), Practice Support Manual, “Disinfection of impressions and appliances before dispatch”, reviewed and updated June 2026. https://www.psm.sdcep.org.uk/topics/infection-prevention-and-control/disinfection-of-impressions-and-appliances-before-dispatch/