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).
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.
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.
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.
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.
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
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.
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.