In vivo effect of mouthwashes on viable viral load of SARS-CoV-2 in saliva: a pilot study

Effectiveness of mouthwashes to reduce the SARS-COV-2 load in saliva of adults with diagnosis of COVID-19: Systematic review and meta-analysis

Background

COVID-19 still represents a threat to public health. In this sense, antiseptic mouthwashes have been suggested to reduce cross-contamination and community transmission.

Material and Methods

This systematic review and meta-analysis aimed to synthesize the evidence on the effectiveness of povidone-iodine (PVP-I), cetylpyridinium chloride (CPC) and chlorhexidine (CHX) mouthwashes in reducing SARS-COV-2 viral load in the saliva of adults diagnosed with COVID-19. After the systematic search in five electronic databases, 16 clinical trials published until June 2023 were analyzed. Of these, 6 were included in the meta-analysis.

Results

The standardized mean difference (SMD) was reported with its corresponding 95% confidence intervals (95%CI). An overall SMD of 0.51 (95%CI: -0.29 to 1.32; I² = 46.0%; p = 0.047) was found. For CPC, the combined effect found in the studies was not significant (SMD = -0.07; 95%CI: -0.42 to 0.28; I² = 0.0%; p = 0.373); the same occurred for CHX (SMD = 0.50; 95%CI: -43.32 to 44.32; I² = 0.0%; p = 1.000). However, PVP-I showed a more consistent profile with a significant combined effect (SMD = 4.15; 95%CI: 2.11 to 6.18) and negligible heterogeneity (I² = 0.0%; p = 0.908).

Conclusions

The findings indicate a non-significant effect of mouthwashes on reducing viral load when all types were evaluated together. Separately, only PVP-I showed a significant reduction in viral load with a low level of certainty of evidence, while for CPC and CHX the reduction was not significant, with a low and very low level of certainty of evidence, respectively. Key words:SARS-CoV-2, mouthwashes, povidone-iodine, cetylpyridinium, chlorhexidine.

Mucoadhesive Pharmacology: Latest Clinical Technology in Antiseptic Gels

Chlorhexidine (CHX) is one of the most widely used antiseptics in the oral cavity due to its high antimicrobial potential. However, many authors have stated that the effect of CHX in nonsurgical periodontal therapy is hampered by its rapid elimination from the oral environment. The aim of this study was to determine the antibacterial efficacy of a new compound of chlorhexidine 0.20% + cymenol (CYM) 0.10% on a multispecies biofilm. For this, an in vitro study was designed using a multispecies biofilm model of Streptococcus mutans, Fusobacterium nucleatum, Prevotella intermedia, and Porphyromonas gingivalis. Quantification of the microbial viability of the biofilm was performed using 5-cyano-2,3-ditolyl tetrazolium-chloride (CTC) to calculate the percentage of survival, and the biofilms were observed using a a confocal laser scanning microscopy (CLSM). It was observed that the bactericidal activity of the CHX + cymenol bioadhesive gel was superior to that of the CHX bioadhesive gel, in addition to higher penetrability into the biofilm. Therefore, there was greater elimination of bacterial biofilm with the new compound of chlorhexidine 0.2% plus cymenol 0.1% in a bioadhesive gel form compared to the formulation with only chlorhexidine 0.2% in a bioadhesive gel form.

Efficacy of different mouthwashes against COVID-19: A systematic review and network meta-analysis

To evaluate the effectiveness of antiseptic mouthwashes in reducing SARS-CoV-2 load clinically and in vitro. A systematic electronic search (MEDLINE/Scopus/Cochrane) was conducted to identify prospective clinical and in vitro studies published between 2019 included and 16 June 2023 assessing the effectiveness of mouthwashes in reducing SARS-CoV-2 load in saliva or surrogates. Data were summarized in tables and a network meta-analysis was performed for clinical trials. Thirty-five studies (14 RCTs, 21 in vitro) fulfilled the inclusion criteria. The risk of bias was judged to be high for 2 clinical and 7 in vitro studies. The most commonly test product was chlorhexidine alone or in combination with other active ingredients, followed by povidone-iodine, hydrogen peroxide and cetylpyridinium chloride. Overall, the descriptive analysis revealed the effectiveness of the mouthwashes in decreasing the salivary viral load both clinically and in vitro. Network meta-analysis demonstrated a high degree of heterogeneity. Among these studies, only chlorhexidine 0.20% was associated to a significant Ct increase in the saliva 5 min after rinsing compared to non-active control (p = 0.027). Data from clinical and in vitro studies suggested the antiviral efficacy of commonly used mouthwashes. Large well-balanced trials are needed to identify the best rinsing protocols.

Assessment of SARS-CoV-2 (COVID-19) Clinical Mouthwash Protocol and Prevalence of the Oral Pathogen Scardovia wiggsiae: A Pilot Study of Antibacterial Effects

One protocol in healthcare facilities and dental offices due to the COVID-19 pandemic for reducing the amount of detectable oral SARS-CoV-2 has been gargling with mouthwash for 60 s. This protocol lasts longer than the daily routine for most patients and may have unexpected benefits in reducing oral microbes as a result. This project evaluated the prevalence of the newly identified oral pathogen Scardovia wiggsiae before and after this procedure to determine any measurable effects. Using an approved protocol, n = 36 pre-mouthwash patient samples, n = 36 matched post-mouthwash samples, and n = 36 matched recall samples were identified (total sample number n = 108). DNA was isolated from each sample (pre-, post-mouthwash, and recall). Screening using qPCR and validated primers revealed n = 10/36 or 27.8% tested positive for Scardovia among the pre-mouthwash (Sample A) isolates with n = 3/36 or 8.3% testing positive among the post-mouthwash (Sample B) isolates. Screening of the recall (Sample C) samples has revealed n = 10/36, or 27.8% once again tested positive for Scardovia, demonstrating that this pathogen was found among a significant proportion of pediatric patient samples. Moreover, the COVID-19-related procedure of requiring sustained mouth washing prior to clinical treatment appears to reduce the levels of detectable Scardovia, at least initially. However, this study found no long-term effects using this isolated protocol.