Dental care

It seems cleaning of teeth is getting common in US and Japan. I think it's good to keep our teeth in good condition. I have some cavities in my teeth, but I thought dental care was not needed. Cavity is caused by bacteria so toothpaste works to kill them because it contains detergents. But it seems not to be true. According to the website of dental care, it says "the plaque is formed by not only colonies of bacteria, but also protozoa, mycoplasmas, yeasts and viruses". It seems our mouth is not clean as we think.