In light of the ongoing discussion on COVID-19 and oral health management, 2,4,26−28 the overarching aim of this triple-blind randomized clinical trial was to evaluate the use of a mouthwash and a dentifrice containing APD on the reduction of clinical symptoms in COVID-19 patients. The results of this study showed reduced clinical symptoms self-reported by patients at home and collected by applying a questionnaire.25 The symptoms’ prevalence were examined at baseline (T0) and 3 (T3) and 7 (T7) days after using APD in oral hygiene products and compared to the control group. These results are in accordance with clinical and laboratorial evidence built over this pandemic period regarding the beneficial effect of using APD in oral care products against COVID-19 in the studies samples.14–16,20−23
Understanding the pathophysiology of COVID-19 with the entry of SARS-CoV-2 through the upper airway, affinities for the nasal and oral mucosae and the salivary glands as reservoirs of the virus,2,29 becomes important to conduct investigations as our study. A recent study found the presence of SARS-CoV-2 in periodontal tissue and concluded that periodontal tissue can be a target for SARS-CoV-2 and contribute to the presence of the virus in saliva.3 In addition, a study aimed to investigate the impact of COVID-19 on the oral health of adults in China and an online cross-sectional survey based on a questionnaire was conducted in a total of 3352 participants. The authors concluded that the three most common oral problems amid the epidemic were gingival bleeding, bad breath and oral ulcers.7 In another study,30 the authors recommend that oral hygiene be maintained, if not improved, during COVID-19 to reduce bacterial load in the mouth and the potential risk of superinfection. The authors also stated that poor oral hygiene be considered a risk of complications, particularly in patients with comorbidity, and that bacteria in patients with severe COVID-19 are associated with the oral cavity and improved oral hygiene may play an important role in reducing the risk of complications. Thus, the habit of oral hygiene through mechanical cleaning should be implemented more rigorously associated with the chemical action against microorganisms, such as SARS-CoV-2.
In the current study, no statistically significant difference was found in the prevalence of clinical symptoms between the groups at baseline (Tables 1, 2). There was a significant reduction in six symptoms self-reported in the Control Group during the follow-up period (Table 3) and a significant improvement (P<0.05) of all major COVID-19 symptoms in the APD group (Table 4). Oral hygiene protocol can reduce COVID-19 symptoms mainly after one week of treatment (Tables 5, 6, 7). Both groups present symptom reduction, however the APD group had a significant reduction during the follow-up (94.9 to 52.9%). These results may be related to the mechanical, antimicrobial, anti-inflammatory and tissue regeneration actions.15,16,20−23 Moreover, according to the safety outcomes, no side effects were reported by the patients regarding the oral hygiene protocol. Thus, the use of oral hygiene as a strategy to reduce the COVID-19 symptoms should be considered.
There is in fact evidence that mechanical oral hygiene can reduce the viral load on the mouth and oropharynx, prevent upper respiratory tract infections, and reduce infectivity.8,11,31,32 In our study, however, we believe that mechanical action was an adjunct that potentiated the action of APD in reducing the load of SARS-CoV-2, which was clinically demonstrated by the greater reduction in self-reported symptoms by patients in the APD Group. Thus, as previously reported, the use of APD in oral care products could positively contribute to the improvement of clinical symptomatology in CODIV-19 patients.22
In addition to mouth and pharyngeal symptoms, diarrhea could happen during COVID-19 infection since SARS-CoV-2 can reach and replicate in intestinal epithelia direct from the mouth.33 In this study, diarrhea was self-reported by patients in both groups at baseline (Control Group: 16, APD Group: 13), and at the end of one week (T7) none of the patients who used the oral hygiene APD protocol presented the symptom, unlike the group that did not use it (Tables 5 and 6). In the Control Group, of the 16 initial cases, 02 remained with diarrhea and 07 new cases appeared during the 7-day follow-up period (data not shown). Thus, based on self-related of the patients, we believe that the APD oral hygiene protocol may have directly contributed to the non-appearance of new cases of diarrhea during the evaluated period, from the reduction of the SARS-CoV-2 viral load in the mouth and pharynx of the patients.
The main limitations of this study were that clinical data on COVID-19 symptomatology was collected from an electronic system at home. Despite the ease of obtaining the information considering the context of the pandemic, without face-to-face interaction with the patients, it made it impossible for us to exclude any symptoms not exclusively associated with COVID-19. Another limitation was with compliance to certify the correct use of oral hygiene products. As it was also conducted electronically, the data from this study were entirely dependent on the fidelity of the responses by the participants. However, the significant reduction in symptoms during the follow-up period showed a promising path for the use of oral hygiene care.
The COVID-19 pandemic has presented moments of exacerbation and improvement, and currently with the arrival of new variants shows that the fight against SARS-CoV-2 should be maintained and intensified and with the results of recent studies, which show the effects of mouthwash in reducing the viral load in the saliva of infected individuals. Therefore, we understand that the strategy of using oral hygiene products containing antimicrobial agents becomes an important adjuvant against SARS-CoV-2.