Also, the toothbrush needs to be of the right kind.  Dentists recommend brushes with a flat surface and soft bristles since these are less likely to injure the gums.  The head of the toothbrush should be small enough to reach all areas of the mouth. 
Dentists also recommend dental flossing to remove plaque from between the teeth.  Plaque is a sticky colorless layer of harmful bacteria tat constantly forms on the teeth.  With sweet foods, bacteria in plaque form acids which attack the tooth enamel and cause tooth decay. 
To remove plaque, you should floss and brush your teeth thoroughly at least once a day since if you do not remove plaque daily, it accumulates then turns into hard deposits called calculus or tartar.  Calculus can be a factor in gum disease and should be removed only by a dentist. 
To Cut Down on Tooth Decay:  
    Avoid too many sweets and sugary drinks
    Clean teeth regularly after meals particularly the side and  back teeth. If you cannot, you may chew gum for twenty minutes to cleanse the teeth.
    Use mouthwashes for their anti-bacterial action
    Avoid using super-whitening tooth polishes since they wear off the tooth enamel
    When brushing teeth use a pen grip instead of the common tennis racket grip to produce less gum abrasion and get rid of the plaque
    Flossing is as important as brushing for plaque control