Start practicing

Prosthodontics & Occlusion · single question

What is the MOST appropriate method for disinfecting an alginate impression immediately after removal from the mouth?

  1. Immerse in glutaraldehyde for 30 minutes
  2. Spray with an approved disinfectant, then bag for the contact time
  3. Allow it to air dry before sending it to the laboratory
  4. Rinse under running water only
Show answer and explanation

Correct answer: B. Spray with an approved disinfectant, then bag for the contact time

  • A. Prolonged immersion is exactly what must be avoided with alginate — it distorts the impression and ruins the cast.
  • B. Correct. Alginate is HYDROPHILIC and dimensionally unstable, so prolonged immersion causes imbibition, swelling and distortion. The correct protocol is: rinse under running water, then SPRAY with an approved intermediate-level disinfectant (typically an iodophor or a diluted hypochlorite), seal in a bag for the manufacturer's contact time, then rinse and pour promptly.
  • C. Air drying causes syneresis and rapid dimensional change; alginate must be poured promptly or stored at 100% humidity.
  • D. Rinsing removes saliva and blood — an essential FIRST step — but it does not disinfect.

Practice Prosthodontics & Occlusion questions Prosthodontics & Occlusion study notes

More Prosthodontics & Occlusion practice questions