Can toothbrushing reduce the intraoral viral load of SARS-CoV-2? A pilot study with a dentifrice containing an antimicrobial phthalocyanine derivative.

The aim of this study was to assess whether toothbrushing with a dentifrice containing an antimicrobial phthalocyanine derivative (APD) can reduce the intraoral viral load of SARS-CoV-2. Twenty COVID-19-positive dentate patients aged ≥18 years were selected instructed to brush their teeth for 2 min with a dentifrice containing APD. Self-collected samples of unstimulated saliva were carried out three times: T0 (baseline), T5 (5 min after toothbrushing), and T30 (30 min after toothbrushing). The analysis of viral RNA was performed by RT-qPCR for detection of three viral genes (ORF1ab, N and S genes). Results were statistically tested using Friedman's test and pairwise comparison with Bonferroni corrections, with a significance level of 5%. There was an increase in the cycle threshold (Ct) value from T0 to T5 in 13 patients (72.2%), and from T0 to T30 in 14 patients (77.8%). In two patients (11.1%) no SARS-CoV-2 was detected at T5 and five patients (27.8%) at T30. The Ct values were statistically significantly higher (p=0.020) at T30 in comparison to T0 and T5. This pilot study suggests that toothbrushing with a dentifrice containing APD could reduce the SARS-CoV-2 viral load in the oral cavity. However, further studies are needed to confirm this possible beneficial effect against SARS-CoV-2.