Discussion
Our study shows that the lockdown in Italy because of the COVID-19 pandemic had a significant impact on both general and dental hygiene of medical students. We selected this population because we assumed that knowledge of the disease and good hygiene practices (i.e., washing hands frequently or wearing a surgical mask) should have mitigated the negative psychological effects of the Covid-19 pandemic. However, it appears that this was not the case. Despite having a good knowledge of general infectious diseases, stress related to COVID-19 strongly affected the examined population. Self-assessment of stress and anxiety showed that almost all students perceived increased fear, anxiety, and stigma.
To our knowledge, this is the only study that specifically explores the effects of stress induced by the COVID-19 pandemic on dental hygiene. Several studies have evaluated the impact of COVID-19 and quarantine-related restrictions on student populations. [2,3,4,7]
A recent survey of medical students during the Covid-19 pandemic, reported an increase in anxiety (61%) and depression (70%). [2] Fear, anxiety, and depression are strongly associated with the development of unhealthy habits, characterized by unhealthy diet, reduced physical activity, and increased sitting time. [11]
A study by Esteves et al. supported these observations, reporting that many students changed their lifestyle habits to maintain social distancing, that is, not practicing physical activities and maintaining contact with friends only via telephone. [3] Distance learning may have contributed to an increase in lifestyle changes. [12,13]
Wilson et al. reported a significant decline in the mental health of college students during the COVID 19 outbreak. In addition, physical activity did not appear to protect against deterioration in mental health. [14]
A previous study showed that the lockdown and restrictions imposed by the Italian government produced psychological distress and anxiety symptoms among students, which negatively impacted their sleep quality and sleep hygiene. [5]
These results are in agreement with ours; we observed increased anxiety among students leading to unhealthy eating and weight gain, reduced physical activity, and increased sitting time.
Personal hygiene and dental hygiene were maintained during quarantine, with only a small group of students reporting a reduction in personal and dental hygiene. However, when we compared the students from dentistry and dental hygiene courses against those from other courses, we observed that the former had better dental hygiene practices. Likewise, they showed better knowledge of the tools used in maintaining oral hygiene.
The lack of knowledge of the tools for oral care by students of other medical courses is surprising. All students belonged to the medical field and were expected to have good knowledge about tools for oral care and hygiene. This is an important issue that needs to be addressed by delving into the aspects of oral disease prevention among medical students. It has been shown previously that oral hygiene plays an important role in the prevention of chronic diseases, such as diabetes and cardiovascular diseases. [15]
The persistence of the pandemic appears to have exacerbated the stress-and stress-related lifestyles of students. [16,17,18,19] Despite efforts to share reliable information on healthy lifestyles, the psychological orientation of young people, particularly their health and food consumption, appears to have not changed during the second wave period. [19]
Interestingly, a large number of students from dentistry and dental hygiene courses reported a change in the quality of mouthwash with an increase in the use of chlorhexidine mouthwash during quarantine. This was because of the effect of some studies that supported the efficacy of mouthwash in fighting the COVID-19 infection. In the study by Cavalcante-Leao et al., in which the asymptomatic patient has been mentioned multiple times, special attention has been given to dental risk since the epithelial cells of the salivary glands have high expression of the angiotensin converting enzyme 2 (ACE2) receptor, which is a functional receptor for COVID-19. They systematically reviewed evidence in the literature regarding the effectiveness of three types of mouthwashes in decreasing the viral load of the oral cavity; the three types of commonly used mouthwashes in dentistry are chlorhexidine, hydrogen peroxide, and povidone-iodine (PVP-I). They concluded that PVP-I, at concentrations of 1% and 7%, appeared to be the most effective mouthwash for reducing COVID-19 viral load in human saliva. However, the level of scientific evidence related to the use of PVP-I mouthwash in reducing SARS-CoV-2 viral load is very low because it was demonstrated only in two in vitro studies. The guidelines for dental care refer to the use of hydrogen peroxide; however, there is insufficient scientific evidence to support this recommendation. [20,21,22]
Our study had some limitations. First, the questionnaires were self-administered, and subjective evaluations were described. No validated tools were used to assess stress and depression among students. Second, we used a web-based survey, which may have resulted in possible selection bias. We selected a restricted cohort of medical students; therefore, it is not possible to extend our findings to the general population. However, this very select population of medical students provides important information on how young individuals perceived the lockdown and the effects it has had on their hygiene habits.