Dear Dr. Burnett,
I hope you're doing well. I understand that I should wait for about an hour to brush my teeth after a meal but what is the ideal time to brush: an hour, 2 hours, 3 hours after a meal?
Good question because there is some disagreement concerning timing and frequency of tooth brushing. One thing is clear from the science. Tooth brushing itself is not reducing tooth decay. It is the fluoride in the toothpaste that stops and reverses decay that is might be starting. The frequency of brushing should be dependent upon the relative risk of the individual for forming new cavities. In general, the less decay and fillings you have, the lower the risk of new decay. The more dental fillings and decay you have, the higher the risk and the higher the need for more frequent brushing(fluoride application).
If one is not at high risk for decay, twice a day brushing with fluoridated toothpaste is sufficient for prevention. High risk calls for more frequent brushing for fluoride application. If you are at low risk for new decay, your toothbrushing should be done when you wake up and just before going to sleep. The toothbrush should be the last thing to go into your mouth before going to bed. Avoid rinsing out the toothpaste. Just spit after brushing and sleep with the fluoride working throughout your sleep time. If you are prone to decay I would suggest the best prevention will come from more frequent fluoride application with your tooth brush. Ideally it should be immediately after eating or snacking on sugary food products. If your risk is very high, I would suggest dipping your toothpaste laden toothbrush into a box of regular baking soda. The baking soda picked up by the wet toothbrush will counteract the acid that forms within the first five minutes of the food reaching your teeth.
You should disregard the information that suggests waiting an hour after eating before brushing. There is no known valid reason for this delay of an hour. That hour is when the acid is working on the tooth to cause decay.
I am guessing that you are low risk because of your interest in prevention. If this is true, I hope my advice will keep you at low risk.
Larry Burnett DDS