Thursday, February 5, 2009


by Dr. H.S. Chawla*
“When should I brush?” is a common query directed at me. Patients, friends and acquaintances want to know whether they should brush in the morning, evening or at night and, secondly, before or after meals.

Generally, one brushes to remove food particles from the teeth. Some of you brush to keep the teeth white and sparkling – which contributes immensely to an overall smart appearance – and others to avoid bad breath. Children brush because their parents tell them to.

The common dental diseases – dental caries and gum diseases – are caused by bacteria in the mouth. Bacteria live in every mouth, on the teeth and the upper surface of the tongue. Bacterial aggregation on teeth is called dental plaque. The difference between a disease-free mouth and one with disease is that the former has lower concentration of bacteria whereas the latter has more.

Bacterial action upon food produces acid. The acid is formed almost immediately upon eating. The acidity of dental plaque increases (in scientific terminology, the pH of dental plaque decreases). Acid erodes tooth enamel (the outer hard layer of the tooth). Many attacks like this on enamel produce cavities in the teeth.

Therefore, the main aim of cleaning your teeth should be to remove dental plaque and reduce bacterial concentration. This keeps teeth free from cavities and gum-disease. When this happens, all other objectives of cleaning the teeth are automatically achieved. Here are various options regarding timing:

Brushing immediately after meals.

There are many nooks and corners in the mouth where bacteria can live and multiply. Because of the tight contact between one tooth and the other, it is practically impossible to get rid of all these bacteria. The acid forms and starts eroding tooth enamel almost immediately upon eating. It takes about 30 minutes for the acidity of the plaque to return to normal.

Thus, brushing right after eating is not at all advised, as the acid produced has already begun the process of eroding enamel. If you brush promptly after a meal, you rub off part of the dissolved minerals of the enamel.

When you brush after meals, you should wait for at least an hour to give time for at least an hour to give time for the acidity of plaque to decrease. It will set the environment for re-mineralisation.

Brushing before meals:

Most people normally brush their teeth in the morning before breakfast. That is beneficial, as you have reduced the number of bacteria before exposing them to food. The amount of acid production is expected to be less, and so would be the damage to the teeth. You get an additional benefit if you use fluoride tooth paste, as the fluoride gets incorporated into the enamel and makes it strong and resistant to the effect of acid. (Fluoride converts the hydroxyl-apatite of enamel to calcium fluor-apatite).

Brushing before dinner

Similarly, based on the above concept, brushing before dinner, indeed, is more beneficial than post-dinner brushing. However, it is essential to get rid of the food particles sticking in the oral cavity after dinner. To achieve this inter dental cleaning along with a little bit of brushing is also needed before retiring to sleep. Otherwise, thanks to the decrease of salivary secretions while we sleep, and the mouth remaining closed for a prolonged period, an ideal environment is created for bacteria to multiply.

Brushing at any time of the day

Thorough brushing at any time of the day is more beneficial than half hearted brushing at selected times. I involves brushing without tooth paste for 5-7 minutes and spitting out each time as the mouth becomes filled with spit, followed by brushing with tooth paste. Inter-dental cleaning with dental floss (or with inter-dental brush) is then carried out. Brush once again with tooth paste.

Thorough brushing whenever you have the time is preferred over half-hearted brushing before or after meals. If you do not spend time on brushing, you are just removing bacteria from one segment of your teeth and re-settling them on another. Brushing before meals is more beneficial than after meals. Brushing immediately after meals should be avoided.

*The writer is Head, Department, The Opollo Clinic, Chandigarh, and Permanent Visiting Professor, The University of Leeds, UK. Email:

(Courtesy: The Tribune 4th February, 2009)


Bacterial action upon food produces acid.
The acid is formed immediately after eating.
Acidity of the dental plaque increases.
Acid erodes tooth enamel (the outer layer of the tooth)
Many attacks like this erosion cause cavity in the teeth.
Main aim of brushing should be to remove dental plaque and reduce bacterial concentration.
Brushing right after meals NOT advised.
Brushing before meals IS beneficial.
Brushing before breakfast is beneficial.
Brushing before dinner is beneficial.
Brushing any time of the day without tooth paste for 5-7 minutes is beneficial.
Thorough brushing for 5-7 minutes without paste followed by brushing with paste preferred over half-hearted brushing.

1 comment:

plug said...

Thanks for clarifying the healthier and more efficient options when brushing teeth.