Dr. Rathin D. Das

MDS Prosthodontics Center head at Illusion training and Education Center

Ex Professor and HOD YMT Dental College, Navi Mumbai


Dental Impressions can act as a mean for different types of micro-organisms like Hepatitis B, C, HIV, Mycobacterium, Herpes simplex, MERS-CoV and the recent one SARS-CoV 2, etc. the most effective way to prevent their spread could be to properly Disinfect them just after taking out of patient’s mouth. This clinical tip would give an effective way to mange the steps to be followed for Disinfection of the Impression. It will also provide information of the concentration of usage along with different available disinfectants.

Keywords : Disinfection, Impression, SARS-CoV 2.

Citations : Das R. Steps for disinfection of impression. J Prosthodont Dent Mater 2020;1(1& 2): 72-73.


In this post COVID-19 era, we should take extra care while handling the impressions from clinic to laboratory as to prevent the Cross-Infection. Most of the bacterias or Viruses could be inactivated by various Chemical Disinfectants.1-3 The ideal disinfectants should have these following properties:

  • Broad Spectrum Activity
  • Act Rapidly
  • Non-Corrosive
  • Environment Friendly
  • Free of Volatile Organic Compounds
  • Non-Toxic
  • Non-Staining

According to CDC Guidelines, the best method to reduce the viral load from Impressions is Chemical Disinfection. Various Chemical Disinfectants used are Glutaraldehyde, Sodium Hypochlorite, Complex Iodophors, Phenols, Chlorhexidine, Alcohols, Quaternary Ammonium Compounds and Simple Detergents. The second most important point of any disinfectant is the appropriate application and contact time.4,5 So, the recommended steps for Disinfection of Impression are as follows

  • Personal protective equipment must be worn.
  • Wash all Impressions thoroughly in running water.
  • Immerse the impression in 5% solution of Sodium Hypochlorite (NaOCl2) for 10 minutes. Ensure the solution is freshly prepared.
  • Re-Wash the impression thoroughly in running water then proceed to pour impression.

The recommended guidelines for preparing 1 litre of the said NaOCl2 solution is

For 5% NaOCl2 – Use 10 ml of NaOCl2 in 990 ml of Water.

For 2.5% NaOCl2 – Use 20 ml of NaOCl2 in 980 ml Water.



1. Centres for Disease Control and Prevention, Interim Infection Prevention and Control Recommendations for patients with suspected or confirmed Corona Virus Disease 2019 (COVID-19) in health care settings, centres for disease control and prevention, Atlanta, GA, USA,2019, https://www.cdc.gov/coronavirus/2019-ncov/hcp/infection-controlrecommendations.html

2. Poulos JG, Antonoff LR. Disinfection of Impressions. Methods and effects on Accuracy. N. Y. State Dent J 1997;63(6):34-6.

3. Maillard JY, Mcdonnell G. Selection and use of disinfectants. In Prac 2012; 34(5):292-9

4. Abdullah MA. Surface detail, Compressive strength, and dimensional accuracy of gypsum casts after repeated immersion in hypochlorite solution. J Prosth dent 2006; 95(6):462-8.

5. National Guidelines For Infection Prevention and Control In Healthcare Facilities, MoHFW, Govt of India.