When talking with parents about their child's oral health habits, I often here the phrase "they brush their own teeth." But what exactly does this mean? For a 2 year old it usually means they suck on the brush. For a 5 year old they will normally swish the brush around for a few seconds then suck off the toothpaste. For kids 6 and older, and most of the rest of us, brushing means about 15-30 seconds.
So, what is appropriate brushing for each age group. I always suggest parents start cleaning the teeth as soon as they erupt. At first you can use a gauze or cloth or soft bristle brush to clean the teeth before bedtime, without using any toothpaste. At about 2-3 you can introduce a toothpaste without added fluoride because your child will most likely swallow it. Never use a hard bristle brush. Let them try to brush first but always follow up brushing yourself. Many 2-3 year olds will go through a phase where they may fight you and close their mouths tightly. Just pry the lips apart and do what you can. This will pass! If you can get a brushing done in the morning and bedtime that's ideal, but not always practical. Children 6 and older should be able to brush themselves, but I still recommend parents check them periodically to see how they're doing. Most kids need constant reminders to brush before going to bed. But brushing "baby" teeth is very important to prevent cavities, maintain space for adult teeth, and give them practice caring for their adult teeth.
Some things that may help: 1) Get a toothpaste they like 2) Use an electric or rotary brush 3) Get a 2 minute sand timer or alarm and have them brush til it goes off 4) Use points, stars, or other rewards for brushing. What I found raising three boys is they needed constant "reminders" until they got to high school when hair, teeth, and clothes suddenly became more important!