This is perhaps the single most-asked question in the history of dentistry. However, dental professionals, to this day, are unable to reach a consensus on the optimal brushing interval for the average person.
Several reasons. Acidic drink and food consumption, genetics, and environmental influences all affect the rate at which it becomes necessary for an individual to brush his/her teeth.
However, the American Dental Association officially recommends that individuals brush twice daily. They do not, however, specify the best times of the day to brush. Generally, it is recommended to brush after breakfast, and before bed. Make it a habit of adding a brushing after lunch as well.
So, why brush anyway? Brushing is very important to maintaining good oral health because it effectively removes plaque buildup that can lead to tooth decay. Be assured, avoiding tooth decay is worth the effort to brush 2-3 times per day.
In summary, if you brush 2-3 times per day you are probably fine. However, if you already brush with this frequency and still notice an inordinate amount of plaque buildup, contact your dentist, because this could be the sign of a more serious oral or medical problem.