166 - Oral health, best hygiene practices, & relationship between oral health and systemic disease

KEYPOINTS

• 01

  The mouth is an ecosystem, not a sterile surface

  Patricia (Pat) Corby trained in Brazil in periodontics and implant dentistry, and now runs clinical trials. She describes more than 700 bacterial species living in symbiosis with the host. Some are protective, some harmful, and a large share (she estimates 30–40%) can play either role depending on conditions. The aim of hygiene is to keep the community in a healthy balance by disrupting the biofilm, not to sterilise the mouth.

• 02

  Caries and gum disease are different infections

  Caries are driven mostly by aerobic, sugar-metabolising bacteria on tooth surfaces. Periodontal disease and gingivitis are driven by anaerobes that thrive below the gumline. They share risk factors (poor hygiene, dry mouth, diet), but brushing reaches the surfaces while flossing reaches the protected spaces between teeth and under the gums.

• 03

  Her twin trial showed flossing matters on top of brushing

  She studied identical-twin adolescents aged about 12–16, who share 100% of their genes and live in the same house. One twin brushed, while the other brushed and flossed, supervised by hygienists every day at a centre and then at home in the evening. The twins who didn't floss had more gingival bleeding and an abundance of the main periodontal pathogens, including Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans, even at that young age.

• 04

  Fluoride toothpaste is the main defence against decay

  Corby disagrees with the view that flossing matters more than brushing. She calls them equally important because toothpaste is the main source of fluoride, which hardens enamel. Look for 1,000–1,500 ppm of fluoride. The American Dental Association lists toothpastes it endorses because they contain an effective amount. Not every toothpaste contains fluoride. She adds that sugar is now in almost everything we buy, a big cultural change that feeds decay-causing bacteria, and that children at high risk can also get fluoride varnish.

• 05

  Night is the riskiest time for your teeth

  Saliva production drops during sleep, so bacteria flourish. That is why babies given bottles overnight get rapid, painful early-childhood caries on the front teeth. She says formula, which contains sugar, causes more decay than breast milk. Brushing and flossing before bed is the single most important hygiene habit.

• 06

  Dry mouth is a hidden risk

  Saliva buffers acid and washes the mouth. Radiation, chemotherapy, anticholinergic drugs and dehydration all reduce it. She urges physicians to ask patients about dry mouth. Sipping water all day helps, since the mouth and gut are 'one system'.

• 07

  Cleaning the mouth may reduce cancer-treatment complications

  Her trial enrols head-and-neck cancer patients (mostly squamous cell, many HPV-positive) receiving at least 50 Gy to the mouth. Almost all of them develop painful oral mucositis. She compares professional mechanical debridement with brushing of the oral mucosa, in blinded groups. Her earlier informal cleanings caught the attention of the radiation oncologist Nicholas Sanfilippo, and a 16-patient pilot won grant funding.

• 08

  Links to systemic disease are mostly associations

  Periodontal disease is associated with diabetes, low birth weight, heart disease and markers of Alzheimer's, plausibly through bacterial insult and inflammation. Corby stresses that we don't know which comes first, and that only trials that treat gum disease and change those markers can show causation. She mentions Angela Kamer's research, including work in people with Down syndrome, who have poor oral health and early Alzheimer's. Attia notes these links could be 'true and unrelated'.

• 09

  Root canals do not cause cancer

  Attia calls claims that root canals cause breast cancer and other diseases nonsensical, and says they cluster with beliefs like vaccines causing autism. Corby explains that older root-canal techniques could perforate roots and seed inflammation, but modern endodontics is far more precise. Attia's objection is partly ethical: a woman with breast cancer shouldn't be told she caused it with a root canal she had five years ago.

• 10

  Tooth colour is mostly environmental

  Genetics and excess fluoride in water can affect tooth shade. But in her twin study, identical twins on the same products ended up very different, with heavy tea drinking darkening teeth. Black tea and red wine are the main stainers. People with darker skin tend to look as if they have whiter teeth because of the contrast, so perceived whiteness is partly relative.