The aim of this study is to analyze if the use of oral antimicrobial solutions and dentifricies are able to reduce the SARS-CoV-2 load in the saliva and oral mucosa. It will be allocated hospitalized patients positive for SARS-CoV-2 (confirmed by RT-PCR of nasopharynx swab tests) and with signs and symptoms of COVID-19. These patients will be divided into two groups: patients enrolled in negative pressure rooms (NPR), and patients enrolled in intensive care units (ICU) with orotracheal intubation. These two groups will receive interventions with oral antimicrobial solutions or dentifrices, containing different compounds. Saliva and oral mucosa swabs will be collected before the intervention, immediately after the intervention, and after 30min and 1h. The primary outcome is to verify if these products can reduce the SARS-CoV-2 load in the saliva and oral mucosa at these time periods, detected by the measurement of the viral load and the fold-reduction.

Each group of patients will receive specific interventions, as follows:

NPR group (n=60) - three interventions with different mouthwashes solutions (12 patients in each intervention): 1) 0.12% chlorhexidine solution (Colgate Periogard®); 2) mouthwash with 1.5% hydrogen peroxide solution (Colgate Peroxyl®); 3) mouthwash with 0.075% cetylpyridinium chloride solution (Colgate Total 12®); 4) 1.5% hydrogen peroxide solution plus 0.12% chlorhexidine solution (Colgate Peroxyl® followed by Colgate Periogard®).

The interventions will be compared with a Placebo, which will be a mouthwash with distilled water (n=12).

NPR group (n=90) - three interventions with different dentifrices (30 patients in each intervention): 1) dentifrice containing only 1.1% fluoride, water, glycerin, cellulose, sodium lauryl sulfate, and sodium bicarbonate; 2) dentifrice containing 0.32% fluoride, 0.96% zinc, arginine, poloxamer, glycerin, water, hydrated silica, sodium lauryl sulfate, and sodium saccharin 3) dentifrice containing 0.454% stannous fluoride, water, sorbitol, hydrated silica, glycerin, tetrasodium pyrophosphate, microcrystalline cellulose, and xanthan gum .

The interventions will be compared to each other. ICU group (n=52)- two interventions with different oral antimicrobial solutions (26 patients in each intervention): 1) 0.12% chlorhexidine solution (Colgate Periogard®); 2) 1.5% hydrogen peroxide solution plus 0.12% chlorhexidine solution (Colgate Peroxyl® followed by Colgate Periogard®).

The interventions will be compared to each other.

Inclusion Criteria:

• Patients positive for SARS-CoV-2 using the RT-PCR method and requiring oral hygiene care and other preventive and therapeutic dental procedures.

Exclusion Criteria:

• Pediatric patients, negative for SARS-CoV-2 by the RT-PCR method, exhibiting oral ulcerations and other erosive lesions in the oral mucosa that contraindicate the use of hydrogen peroxide, chlorhexidine and cetylpyridinium, patients who present bleeding in the oral cavity. that prevents the collection of samples, patients who report a history of allergy, irritations or other side effects derived from the use of these substances, who do not adhere to the oral care protocols or those in which it is not possible to perform these procedures.