Cách đánh răng đúng cách: kỹ thuật Bass cải tiến cho từng vùng răng

Brushing every day yet still leaving plaque along the gumline and on the inner surfaces is very common. Knowing how to brush your teeth properly is not about brushing longer or harder; it is about where the bristles reach and whether you cover the whole mouth. This guide covers the modified Bass technique area by area, an easy brushing route and common mistakes.

What is the modified Bass technique?

The Bass technique targets the gum groove, the small gap between tooth and gum where plaque collects and causes gingivitis. The bristles are angled at about 45° toward the gum so some of them slip into the groove, then vibrated back and forth in very short strokes. The “modified” version adds one movement: roll the bristles from the gum toward the biting edge to sweep plaque away.

A review by Wainwright and Sheiham (2014) found that modified Bass was the method most often recommended by dental associations, manufacturers and textbooks (19 sources), ahead of Bass (11), Fones, a large circular motion (10), and the scrub technique (5); the authors said the advice varied far too much (PubMed). The 2024 consensus from the FDI World Dental Federation did not single out a technique but advised comprehensive brushing, for example with the (modified) Bass or Fones technique, cleaning every tooth surface and the gums; people with periodontitis should pay particular attention to the gumline (Glenny et al., International Dental Journal).

What does research say: which technique cleans best?

• Poyato-Ferrera et al. (2003): 46 non-dental students, 3 weeks. Modified Bass removed significantly more plaque than their usual brushing, especially on inner surfaces (about 2.9 times as effective). PubMed
• Weng et al. (2023): 180 people, 4 weeks. Modified Bass, the rolling technique and current brushing gave similar overall results; modified Bass cleaned the gum margin better but was harder to master. PubMed
• Harnacke et al. (2012): 56 students taught by computer presentations, followed for up to 28 weeks. The Fones group cleaned better and had healthier gums than the Bass group; the study was sponsored by a toothpaste company. PubMed

So no technique has been proven best for everyone. Modified Bass has an edge at the gumline but takes practice; the surest rule is to reach every surface.

How to brush your teeth properly: 4 basic steps

Use a soft brush and fluoride toothpaste. Vinmec (a Vietnamese source) also advises brushing 2–3 teeth at a time, about 5–10 strokes each, rather than sweeping the whole arch at once.

1. Angle the brush toward the gumline: bristles touch tooth and gum at about 45°, pressing just enough to slip into the gum groove without splaying.
2. Brush 2–3 teeth at a time: vibrate in place, roll the bristles toward the biting edge, then move on, overlapping one tooth from the previous group.
3. Brush the chewing surfaces and tongue: short back-and-forth strokes on the chewing surfaces; finish by gently brushing the top of the tongue from back to front.
4. Spit and rinse the brush: spit out the foam without rinsing your mouth with lots of water; rinse the brush under the tap and let it dry.

FDI advises brushing long enough to clean every surface, typically around 2 minutes depending on the number of teeth and dexterity. Why you should spit rather than rinse is explained in our article on fluoride toothpaste.

How to clean each area

Outer and inner surfaces of the back teeth

Hold the brush along the arch with the bristles toward the gum: up on the upper teeth, down on the lower teeth. On the inner surfaces, keep the angle toward the gum on the tongue or palate side. For the back molars, half-close your mouth so the cheek relaxes; on the lower inner surfaces, push the tongue gently aside.

Inner surfaces of the front teeth: brush upright

The front arch is curved and narrow, so a horizontal brush head cannot sit flat. Tilt the brush vertically, place the bristles at the tip of the head on the gumline and make several up-and-down strokes, as the American Dental Association (ADA) advises (MouthHealthy – ADA).

Chewing surfaces and tongue

Short back-and-forth strokes let the bristles reach the grooves of the molars. For the tongue, a few gentle strokes or scrapes from back to front are enough; the evidence is covered in causes of bad breath and what helps.

If you use an electric toothbrush

FDI notes that both manual and powered toothbrushes depend on user technique. With an electric brush, keep the angle toward the gumline and work tooth group by tooth group, but skip the hand vibration and rolling: just hold for a few seconds and glide to the next tooth. For a comparison of the two, see are sonic electric toothbrushes any good.

A brushing order that misses nothing

Winterfeld et al. (2015) filmed 101 eighteen-year-olds in Germany brushing as usual. They brushed for about 156 seconds on average, yet inner surfaces got only about 27 seconds versus 72 seconds for outer surfaces, and they switched areas about 45 times (PubMed). The same group found that spreading brushing time evenly across the mouth predicted cleaner teeth afterwards (Harnacke et al., 2015). So pick a fixed route, for example:

1. Upper teeth, outer surfaces: right to left.
2. Upper teeth, inner surfaces: left to right.
3. Lower teeth, outer surfaces: right to left.
4. Lower teeth, inner surfaces: left to right, slowing down at the front teeth and back molars.
5. Chewing surfaces of both jaws, then the tongue.

Common brushing mistakes

• Scrubbing hard from side to side: easily skips the gum groove; Vinmec notes incorrect brushing can wear teeth and cause sensitivity, and advises against horizontal brushing.
• Brushing straight after acidic food: wait a while first; the reason is in sensitive teeth when brushing.
• Missing the lower inner surfaces: they get less brushing time, and the tongue is in the way.
• Pressing too hard: bristles splaying sideways mean too much force.
• Rinsing straight away with lots of water: FDI advises spitting out excess toothpaste without rinsing; use mouthwash at another time.

Inmax electric toothbrushes to consider

If you want to apply these steps with an electric brush, these three models offer several modes so you can pick a vibration level that suits your gums:

• M2 Art: 250–400 Hz, the highest frequency in the M2 family; 5 modes including Soft and Strong; a colour icon display shows the active mode.
• M3: 248–320 Hz; 5 modes including Sensitive; box includes 2 extra brush heads.
• M5: 20,000 vibrations per minute; Gum Care mode; 199.4 mm body, the shortest of the Inmax electric toothbrushes.

All three use a 1,200 mAh battery, Type-C charging and IPX7 water resistance. Their specifications do not list a timer, so you still need to keep time yourself using the route above. Browse the electric toothbrush range, compare specifications or contact Inmax; retailers can see our dealer policy.

Frequently asked questions

How many times a day should I brush?

FDI recommends at least twice a day, including once last thing at night before bed.

How long is long enough?

Around 2 minutes is a useful guide, but the real goal is to clean every surface. In the video study, many people brushed for over 2 minutes and still neglected inner surfaces.

Does a hard brush clean better?

No need. FDI advises a small brush head with soft or medium bristles, since firmness varies between manufacturers.

Where should a beginner start?

Practise in front of a mirror on the outer surfaces of the front teeth until the angle and short vibrating strokes feel natural, then extend to other areas. Asking your dentist to check at your regular visit is the quickest way to know you are doing it right.

This article offers general information on brushing technique and does not replace advice from a dentist who has examined you.