Rinsing a Pandemic Down: Effects of Oral Hygiene in SARS-CoV-2: A Two-Center Prospective Pilot Study

Area of Science:

• Oral medicine and diagnostics
• Virology and infectious disease
• Dental public health

Background:

• Saliva sampling offers a comfortable, low-risk method for respiratory virus detection in dental settings.
• The impact of daily oral hygiene, rinsing, and eating on SARS-CoV-2 detectability in saliva requires further investigation for clinical application.

Purpose of the Study:

• To investigate how mechanical oral hygiene, mouth rinsing, and food intake affect short-term SARS-CoV-2 RNA levels in saliva.
• To assess the reliability of saliva diagnostics in dental settings considering routine patient behaviors.

Main Methods:

• A pilot study involving 12 COVID-19 patients who provided paired saliva and pharyngeal swab samples.
• Assessed the effects of a 3-minute intensive oral hygiene protocol, repeated mouth rinses, and post-meal sampling on viral RNA quantification via RT-PCR.

Main Results:

• Pharyngeal swab cycle threshold (Ct) values were stable, while mouth-rinse saliva samples showed significant fluctuations.
• Oral hygiene and rinsing increased Ct values by an average of 3 units, indicating reduced viral RNA.
• Eating increased Ct values by 4-5 units in swabs and 3-11 units in saliva samples.

Conclusions:

• Saliva diagnostics are feasible in dental settings but influenced by common behaviors.
• Mechanical oral hygiene, rinsing, and eating can transiently decrease detectable SARS-CoV-2 RNA.
• Standardized pre-analytical instructions for saliva sampling are needed to improve test reliability in dental care.