Do we need to brush our teeth?

Question

While everyone is telling us that we should brush our teeth twice a day, the human species has evolved for several million years without any teeth brushing. Apes don't brush their teeth, and they don't have a mechanism to change their teeth like sharks and crocodiles.

So why do human need to brush their teeth?

If we do, do we only need to brush them to clean and remove food stuck in them, or is the use of Fluoride based toothpaste is needed as well?

Answer 1

Do we need to brush our teeth?

Yes, there are health benefits from brushing your teeth. Done correctly, it reduces the incidence of caries and periodontitis.

When you brush your teeth, you help remove plaque — a sticky film that forms on your teeth because of bacteria in your mouth. The bacteria in plaque causes the two major tooth-related diseases, cavities (dental caries) and gum disease (periodontitis).

Mayo clinic

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In normal use it must be concluded that the benefits of tooth brushing far outweigh the potential harm.

Can tooth brushing damage your health? Effects on oral and dental tissues.

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The Cochrane Collaboration performed a meta-analyses of several studies:

The review of trials found that children aged 5 to 16 years who used a fluoridated toothpaste had fewer decayed, missing and filled permanent teeth after three years (regardless of whether their drinking water was fluoridated). Twice a day use increases the benefit.

In another meta-analysis, they looked at young children, and found that may be side-effects of fluoride toothpastes - a risk of fluorosis/mottling of teeth - especially in children younger than 12 months or under 5-6 years with high fluoride levels, but that for children at high-risk of tooth decay, this risk may be outweighed.

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the human species has evolved for several million years without any teeth brushing. ... So why do human need to brush their teeth?

^{From EPIDEMIOLOGY OF DENTAL DISEASE}

As others have pointed out

• We don't eat what people ate 5000 years ago (let alone 150000 years ago)
• We need our teeth to last longer as we mostly don't expect to die before age 40.

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Studies of the dentitions of ancient English populations show that a change in the prevalence and distribution of caries took place between the seventeenth and nineteenth centuries and was closely associated in time with an increase in the consumption of refined carbohydrates, especially sugar.

^{From The role of sugar in the etiology of dental caries via Wikipedia}

Bacteria in a person's mouth convert glucose, fructose, and most commonly sucrose (table sugar) into acids such as lactic acid through a glycolytic process called fermentation.

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Apes don't brush their teeth

That doesn't mean they wouldn't benefit from so doing.

Caries is moderately common among the great apes, particularly the chimpanzees. Of the great apes, chimpanzees have a diet most similar to our own;

EPIDEMIOLOGY OF DENTAL DISEASE

Caries in great apes is usually observed later in life when occlusal enamel is lost through wear and approximal enamel that maintains a tight contact between teeth breaks down and allows food and plaque stagnation between teeth.

Dental Biology and Disease

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is the use of Fluoride based toothpaste ... needed as well?

Many medical professionals believe there is adequate evidence to support this.

Most toothpastes also contain fluoride, which helps to prevent and control cavities.

NHS

Multivariate analysis disclosed fissure sealants, early start of tooth brushing and topical fluoride application to be associated with the prevention of dental caries.

Evaluation of a preventive program aiming at children with increased caries risk using ICDAS II criteria.

Answer 2

Summary:

• A. Using fluoridated toothpaste in both children and adults reduces the risk of dental caries.
• B. Fluoridated toothpaste increases the risk of dental fluorosis only when children 8 years old or younger swallow it, in which case fluoride is absorbed, enters the blood and from there the teeth. Fluoride in children in adults does not enter the teeth through their surfaces, for example, during brushing the teeth.
• C. Brushing teeth immediately after eating acidic foods or drinks (fruits, cola, fruit juices) can damage tooth enamel.

http://www.ncbi.nlm.nih.gov/pubmed/14960006

The results revealed strong evidence (level 1) for the caries preventive effect of daily use of fluoride toothpaste compared to placebo in the young permanent dentition and that toothpastes with 1,500 ppm of fluoride had a superior preventive effect compared with standard dentifrices with 1,000 ppm fluoride.

Claims 1-5 http://lpi.oregonstate.edu/infocenter/minerals/fluoride/

1. Topical use of fluoride (including fluoridated toothpaste) reduces the risk of dental caries in children and adults

2. It is swallowed fluoride, which enters circulation and ends in teeth (until 8 years of age) and can cause dental mottling and not fluoride in the toothpaste - except when children swallow large amount of toothpaste. Small children can swallow 0.3 mg fluoride per brushing , which is about 1 mg per day.

3. According to the U.S. Institute of Medicine (IMO), adequate intake (which reduces caries risk and does not cause tooth mottling) for fluoride for children 1-3 years old is 0.7 mg/liter and for 4-8 years olds 1 mg/liter (see reference above).

4. In the U.S., fluoridated water contains 0.7-1.2 mg fluoride/liter.

5. In areas with 1 mg fluoride/liter tap water, about 10% of mild fluorosis in population was observed, and in areas with 2 mg fluoride/liter, 5% of moderate fluorosis was observed.

6. http://www.ncbi.nlm.nih.gov/pubmed/18435369 Tooth brushing after acidic meals is more harmful than brushing before acidic meals.