Randomization and masking
Sample randomization was performed as follows: the mouthwash bottles and nasal sprays were placed in consecutively numbered closed packages. An Excel (Microsoft, Redmond, WA, US) database was created from these numbered packages and used for randomization. After randomization, packages with mouthwash bottles, oral care kits (dental floss, toothbrush, and fluoride toothpaste, Rabbit Corp, Brazil), and nasal sprays were delivered to the participants.