I have a real "system" about this ... I brush after I've had anything to eat. So, if I eat 5 times a day (including snacks), then I brush afterward, using a very powerful power-brush. I also floss and use a water irrigator (water jet) to remove as much trapped food as possible, and I use a good mouthwash. This might sound excessive, but trips to the periodontist are very expensive, and taking expert care of the teeth and gums means no surgery later on.