It is recommended to brush your teeth twice a day to maintain good oral hygiene.

noli's read

The advice to brush teeth twice a day is the golden rule for maintaining good hygiene and a bright smile. A major meta-analysis published in the *Journal of Dental Research* confirms that brushing teeth less than twice a day is directly linked to a more rapid accumulation of plaque and a weakening of the enamel. Guidelines from the Union Française pour la Santé Bucco-Dentaire (expert opinion) also recommend this rhythm of two daily brushings of two minutes to effectively clean all surfaces. Regarding the idea of letting the previous day's toothpaste "take effect," observational data show that plaque begins to reform in just a few hours, making regular mechanical action essential. Thus, the regularity of brushing morning and evening remains scientifically validated to maintain comfortable gums and fresh breath on a daily basis.

the sources

No named source held this one up — that absence is part of the verdict.