Tooth Brushing Timer

Dental associations worldwide recommend brushing for two minutes, twice a day, with a fluoride toothpaste. Studies that measured plaque removal found that most people stop after about 45 seconds and that going from 45 seconds to two minutes removes roughly 25 % more plaque; going beyond two minutes adds little. The problem is not knowing the rule, it is that 45 seconds feels like two minutes. A timer fixes that.

The quadrant guide splits the two minutes into four 30-second blocks, upper right, upper left, lower left, lower right, with a soft tone at each change. Without a prompt people over-brush the front teeth they can see and under-brush the back molars, which is where cavities and gum disease usually start. Thirty seconds per quadrant covers the outside, inside and chewing surfaces of each group.

1. Hold the brush at about 45 degrees to the gum line, bristles pointing towards the gum.
2. Use short, gentle strokes or small circles; scrubbing hard wears enamel and recedes gums. A soft brush is enough.
3. Outside surfaces first, then the inside surfaces (tilt the brush vertically for the front teeth), then the chewing surfaces.
4. After the last quadrant, brush the tongue lightly and spit, don't rinse: rinsing washes the fluoride away before it can work.

Electric brushes do the strokes for you, and most already buzz every 30 seconds; the timer here is for manual brushes, for children's brushing and for anyone whose electric brush has lost its pacer.

Children need help brushing until they are about seven or eight, and a visible timer turns the two minutes from a negotiation into a game. Let the child watch the quadrant indicator move and "beat" the clock. Use a pea-sized amount of fluoride toothpaste from age three (a smear before that), and brush last thing at night and one other time. The tone at each quadrant change also works for adults with braces, who should spend extra time around brackets and are often advised to brush for three minutes; set the custom time accordingly.

Floss or use interdental brushes once a day; the timer is not needed, but doing it before brushing at night is the easiest habit to keep. The habit tracker is a simple way to keep a streak going for a new routine, and the shower timer helps keep the rest of the morning on schedule.