Oral Hygiene Habits and Possible Transmission of COVID-19 Among Cohabitants

Maria Jose Gonzalez-Olmo; Bendicion Delgado-Ramos; Ana Ruiz-Guillen; Martin Romero-Maroto; Maria Carrillo-Diaz


BMC Oral Health. 2020;20(286) 

In This Article


Design Type

This was a cross-sectional, observational study conducted in Spain for fifteen days (April 15–30 2020), four weeks after the start of the confinement in Spain.

Data Collection

These data collection efforts were particularly designed to avoid person-to-person contact. It was an online study, and only participants with Internet access could participate in the study. A snowball sampling technique was used. An anonymous online questionnaire was developed using Google forms with a consent form attached. The link to the questionnaire was sent by email, WhatsApp and other social networks through the researchers. Participants were encouraged to complete the survey with as many people as possible. Therefore, the link was forwarded to people apart from the first point of contact, etc.

Included participants were over 18 years old, able to understand Spanish, and willing to give an informed consent. A total of 2305 subjects agreed to the survey, but only those subjects who had a confirmation in PCR (Polymerase Chain Reaction) of a COVID-19 infection and who were living with another person with whom they shared a bathroom were selected, the sample being reduced to 302 subjects included in the analysis. The survey and consent to participate were approved by the King Juan Carlos University Ethics and Research Committee (Registration number: 0103202006520).


The structured questionnaire (included as supplementary file) consisted of questions covering several areas: (1) sociodemographic data (age, gender and educational level), (2) cross transmission to another person living in the same home and sharing a bathroom, with a response format carried out via a dichotomous question (yes = 1/no = 0), (3) oral hygiene habits during confinement (brushing 2 or more times per day, flossing once per day, mouth rinsing once per day, brushing tongue once per day). Responses were rated on a 5-point Likert scale ranging from 1 to 5, with "Never" = 1, "Almost never" = 2, "Sometimes" = 3, "Almost always" = 4 and "Always" = 5. Questions also covered (4) care and disinfection control behaviors in the dental environment (Usually sharing a toothbrush, usually sharing a toothbrush container, usually sharing toothpaste, usually placing brush vertically, usually placing cap with hole for brush, usually disinfecting brush with bleach, usually closing toilet lid before flushing, changing toothbrush after COVID-19 + test). The response format was carried out via a dichotomous question (yes/no).

Statistical Analysis

The study presents a cross-sectional descriptive study, in which the variables considered are those described in the previous section. Statistical analysis was performed using the SPSS version 24 (SPSS Inc., Chicago, IL, USA). Data analysis included descriptive statistics and the Kolmogorov–Smirnov test to evaluate the assumption of normality, which was confirmed. In order to know the possible differences between groups with infection from a single family member and those with an extension to more than one household member, T tests were performed in the case of quantitative variables and Chi-square tests in the case of variables. Significance levels were established at 0.05.