The Case for Pre-procedural Rinsing

Date: September 2020

Author: Dr Natalie Bradley BDS MFDS Dip SCD RCSEd

We are all concerned about the transmission of COVID-19 right now, not only when out and about in public, but especially when providing dental treatment for our patients. COVID-19 is transmitted mainly in three ways in the dental care setting: Inhalation, direct transmission via exposure of mucous membrane such as eye, nasal or oral mucosa, and indirect transmission via contaminated surfaces. One of the measures many dental clinics are implementing as additional infection prevention control, is the use of a pre-procedural rinse for patients before dental treatment. This article will explain the rationale behind this move.


It is well known that the oral cavity is colonized by various oral micro-organisms which become aerosolized during certain dental procedures.

The WHO recommends the use of pre-procedural rinses to reduce the salivary load of oral microbes, including the viral load of SARS-CoV-2. While there is a lack of direct evidence for viral load reduction, it is well known that pre-procedural rinsing reduces bacterial loads and has been shown to decrease the numbers of colony-forming units (CFUs) cultivated on petri dishes in studies.

What Types of Dental Procedures Generate Aerosols?

Dentistry frequently performs treatments which create aerosols which can increase the risk of viral transmission. According to WHO, aerosol generating procedures (AGPs) in oral health include:

  • All clinical procedures that use spray generating equipment such as the three-way air/water spray
  • Use of an ultrasonic scaler
  • Any kind of dental preparation with high- or low-speed handpieces (e.g., preparation for direct restorations, crown or bridgework, polishing teeth)
  • Definitive cementation of crown or bridgework
  • Surgical tooth extraction
  • Implant placement

Which mouth rinse?

A number of different mouth rinses have been recommended by different associations and societies. These recommendations are varied on which mouthwash, how long and how often your patients should rinse. In addition, use of a commercial rinse for pre-procedural rinsing is an off-label use.

Many groups and organizations recommend the use of 1% or 1.5% hydrogen peroxide (such as Colgate Peroxyl) or 0.2% povidone-iodine, which are both biologically plausible. These are recommended because SARS-CoV-2 and similar viruses are susceptible to oxidation. There is no consensus across all groups however on which rinses should be recommended.

Dental practitioners should ensure that patients are able to rinse for the specified time and may consider repeating the rinse during prolonged treatment. It should be noted that practitioners should also ensure that patients have no confirmed allergies or sensitivities to an ingredient in a mouth rinse, prior to giving them it for pre-procedural rinsing.

Using a mouth rinse to decrease the microbial bioburden would seem to be a simple, safe and efficient way to help to decrease the microbial contamination in aerosols.

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