More than healthy teeth

Media item: article

Date published: 14 August 2014

Subject: oral health and general health

This page records the media item. The original article is the property of its publisher and is not reproduced here.

The link is real. The claims made about it are often overstated.

The connection between oral health and general health is well established as an association. What is much less certain, in most cases, is whether it is causal — whether treating one improves the other. Two articles cover the same ground: Dental health and general wellbeing and The importance of dental hygiene: a window onto overall health.

This distinction matters, because "gum treatment prevents heart attacks" is the kind of claim that would breach the advertising provisions of the National Law by creating an unreasonable expectation of benefit. So here is what the evidence actually supports, graded honestly.

The strongest link: diabetes

This is the one with genuine two-directional evidence, and it is the only association on this page where we can put published figures against each claim. See Diabetes and dental health: the two-way street that most people don’t know about and Diabetes and oral health.

Diabetes increases the risk and severity of periodontitis. Poorly controlled diabetes impairs the immune response and healing; periodontitis is more common, more severe and more rapidly progressive in people with poor glycaemic control. The peer-reviewed literature puts the risk of periodontitis at approximately threefold in people with diabetes compared with people without it, and glycaemic control is the key variable: in the US NHANES III survey, adults with an HbA1c above 9 per cent had a significantly higher prevalence of severe periodontitis than people without diabetes — odds ratio 2.90 (95% CI 1.40 to 6.03), after controlling for age, ethnicity, education, sex and smoking. See What is periodontal disease?
Periodontitis appears to worsen glycaemic control, and there is reasonable evidence that treating periodontitis produces a modest improvement in HbA1c — the reviewed estimate is a reduction of approximately 0.4 per cent. Small in absolute terms, and clinically meaningful at a population level. What that treatment involves is described in Do I need a deeper cleaning? and at Periodontists.
And the complication data is where it stops being abstract. In people with diabetes, the incidence of macroalbuminuria and of end-stage renal disease are increased twofold and threefold respectively where severe periodontitis is also present, and the risk of cardiorenal mortality — ischaemic heart disease and diabetic nephropathy combined — is around three times higher, reported as 3.2 times (95% CI 1.1 to 9.3) after adjustment for age, sex, diabetes duration, HbA1c, macroalbuminuria, BMI, cholesterol, hypertension, ECG abnormalities and smoking. The published conclusion is that "oral and periodontal health should be promoted as integral components of diabetes management".

Practical consequence: if you have diabetes, periodontal care is part of your diabetes care, and your dentist and GP are treating the same inflammatory problem from different ends. Tell each about the other.

And there is a gap in the Australian system worth knowing about. Diabetes Australia’s own material points out that dental visits are not formally included in the Annual Cycle of Care for diabetes in Australia — the cycle covers blood pressure, HbA1c, cholesterol, kidney function, podiatry and eye examinations, and oral health is missing from the checklist. Nobody will prompt you. You have to raise it.

And in reverse: severe or unusually rapid gum disease in someone not known to be diabetic is a reason for a practitioner to suggest a GP check blood glucose. Dentists do occasionally find undiagnosed diabetes this way. The first sign is usually bleeding gums — see What is gum disease?

Cardiovascular disease: association, causation unproven

People with periodontitis have more cardiovascular disease. That association is consistent across many studies — see Health problems linked to poor oral hygiene.

What is not established is that periodontitis causes it. The two share substantial risk factors — smoking, diabetes, obesity, age, socioeconomic disadvantage — and adjusting for those attenuates the association considerably. Major cardiology and periodontal bodies have generally concluded that the association is real but a causal link is not proven, and there is no good evidence that treating gum disease reduces cardiovascular events.

The honest statement: treat gum disease because it destroys the bone holding your teeth in and is the leading cause of adult tooth loss. That is reason enough. Do not treat it in the belief that it is preventing a heart attack. On the longevity claims that circulate, see Can good oral hygiene increase lifespan?

Pregnancy: care is safe, and the outcome claims are weaker than advertised

Two separate things get conflated here.

First, and unambiguous: dental care during pregnancy is safe and is recommended. See Is it safe to visit the dentist in pregnancy?, Oral health care while pregnant and the archive item Labour of Love. Pregnancy gingivitis is very common — hormonal changes exaggerate the gum response to plaque — and morning sickness causes acid erosion of the palatal surfaces of upper teeth; see What is acid wear and how can I avoid it? After vomiting, rinse with water or a bicarbonate solution and do not brush immediately, because softened enamel abrades — see Over-brushing. Routine examinations, cleans and necessary treatment can and should proceed; some elective treatment and imaging is deferred, and radiographs when genuinely needed are taken with appropriate protection. On dose, the International Atomic Energy Agency gives 1 to 8 microsieverts for an intraoral dental X-ray and 4 to 30 microsieverts for a panoramic examination — see How safe are dental X-rays?

Second, and more equivocal: periodontitis is associated with preterm birth and low birthweight, but trials of periodontal treatment during pregnancy have generally not shown that treatment improves those outcomes. So the association is real; the intervention has not been shown to change the outcome.

The correct message is therefore: see a dentist during pregnancy because your gums need it and treatment is safe — not because it will prevent a preterm birth. See also Why are women especially prone to oral health problems?

Aspiration pneumonia in frail older people: a real association, and thinner trial evidence than you will read elsewhere

This one is under-appreciated, and it is also where this page used to overstate its own case. The association is real. The evidence that improving mouth care actually prevents pneumonia is weaker than it is usually reported to be, and we would rather say so than repeat a claim we cannot stand behind.

Poor oral hygiene in dependent older people — particularly in residential aged care — is associated with aspiration pneumonia, where oral bacteria are inhaled into the lungs. That association is not in dispute, and the mechanism is plausible: dental plaque in dependent older adults is frequently colonised by respiratory pathogens, and aspiration of oropharyngeal fluid carries them into the lower airway.

What the trials show is narrower than the headline. The current systematic review is Oral care measures for preventing nursing home-acquired pneumonia, Cochrane Database of Systematic Reviews 2022, Issue 11, CD012416 — six randomised trials, 6,244 nursing home residents, from Japan, the United States and France.

On whether residents get pneumonia at all, five trials in 5,018 residents gave "insufficient evidence of a difference" between professional oral care and ordinary self-administered care. Cochrane rates that low-certainty evidence, downgraded two levels for risk of bias and imprecision.
On dying of pneumonia, two trials in 454 residents found professional oral care may reduce pneumonia-associated mortality at 24 months — risk ratio 0.43, 95% CI 0.25 to 0.76, which corresponds to roughly 71 deaths per 1,000 instead of 165. Also rated low certainty, and in one of those two trials 38 per cent of participants were lost to follow-up on that very outcome.
All six trials were judged at high risk of bias. None was Australian. And no trial has ever compared oral care with no oral care — the comparison is always professional or assisted care against the resident managing alone.

The review’s own conclusion is that "the effect of professional oral care on preventing NHAP remains largely unclear". So the strongest signal is on deaths rather than on infections, and even that is low-certainty. Anyone who tells you this is settled is reading the abstract they wanted. See Health problems linked to poor oral hygiene, In my late 60s, can I keep my teeth in top condition now I am older? and Oral health care for children with special needs, which describes assisted mouth care from the other end of life.

So why does daily mouth care in aged care still matter? Because the reasons that do hold are sufficient on their own, and none of them depends on the pneumonia question. The Aged Care Quality and Safety Commission’s own provider guidance puts it in terms of the resident’s ability to "eat, drink, communicate and sleep", their confidence, dignity and mental wellbeing, and the dehydration, malnutrition and weight loss that follow when a painful mouth stops someone eating. Notably, that guidance does not claim pneumonia prevention either. Daily mouth care for someone who cannot manage it themselves is a genuine clinical intervention, not a cosmetic nicety, and it is frequently not done — which remains one of the most neglected areas of Australian health care. See What is the ideal daily routine for oral hygiene?

Other associations worth knowing, with appropriate caution

Rheumatoid arthritis and periodontitis are associated, with shared inflammatory mechanisms proposed. Interesting; not established as causal.
Chronic kidney disease, and dialysis, complicate dental care and are associated with worse periodontal health.
Osteoporosis matters mainly through its treatment — antiresorptive medications and the risk of osteonecrosis of the jaw after extractions. See Dental Implants and Wisdom Teeth.
Head and neck radiotherapy permanently reduces saliva and causes rampant decay; dental assessment before radiotherapy is essential, because extractions afterwards carry a serious risk of osteoradionecrosis. On the saliva side, see My mouth is always dry.
Eating disorders produce a characteristic erosion pattern on the palatal surfaces of the upper teeth, and dentists are sometimes the first to notice — see How is dental erosion addressed?
Immunosuppression and chemotherapy raise the risk of oral infection and mucositis; dental assessment beforehand is standard. See The cause of mouth ulcers and their usual treatments.

The one that is not an association but a direct finding: oral cancer

The dental examination includes screening the soft tissues for head and neck cancer — the tongue, including underneath it, the floor of the mouth, the cheeks, palate and throat, plus the lymph nodes in the neck. See Oral cancer: how a dentist can help with early detection and Oral cancer: signs and risk factors.

The risk factors are smoking and alcohol — substantially multiplicative when combined — and HPV for oropharyngeal cancers. The RACGP’s own list, written for general practitioners, is age over 45 (especially in men), tobacco use, alcohol consumption, areca (betel) nut chewing, and limited access to dental care, and it notes that areca nut chewing is a growing practice in Australia. See What are the causes, symptoms and treatment of mouth cancer? and, on vaping, The effects of vaping on your oral health.

Any ulcer, white patch, red patch or lump that has not healed in three weeks needs examining. The RACGP sets the threshold at "more than two to three weeks" for any unexplained or non-healing change in the mouth — a persistent ulcer, red patches, lumps, a sore throat, or erythematous or speckled lesions — and states plainly that "initial lesions of oral cancer are generally painless", which is exactly why a symptom threshold does not work and a time threshold does. Oral cancer is far more survivable when found early.

This is the reason to see a dentist even if you have no teeth at all, which is exactly the group least likely to attend — see Dentures.

What all of it comes down to

The mouth is not separate from the body, and the same things that damage one damage the other: smoking, sugar, alcohol, uncontrolled diabetes, and the socioeconomic disadvantage that determines access to all care. See How does sugar affect your dental health? and The impact of wine on teeth.

Smoking is the largest modifiable risk factor for periodontitis, as well as for oral cancer, implant failure and poor healing; the peer-reviewed summary is that it "significantly increases risk for periodontitis and severity of the condition", alongside diabetes and conditions involving compromised immunity. It also masks the disease — smokers’ gums bleed less because the vasculature is constricted, so periodontitis in a smoker is often more advanced than it looks. See also Are e-cigarettes bad for teeth?

And the most useful practical instruction on this entire page: tell your dentist your full medical history and every medication you take, and tell your doctor about your oral health. They are treating the same person. See General Dentistry and Understanding Your Treatment.

Common questions

If I have diabetes, what should I actually ask my dentist and my GP?

Ask your dentist to measure and record your gum health properly rather than only looking, and ask what your pocket depths and bleeding scores are. Ask your GP or diabetes educator whether your oral health is being reviewed at all — Diabetes Australia’s own material notes that dental visits are not formally part of the Annual Cycle of Care in Australia, so it is not prompted by the system. And tell each about the other: the reviewed estimate is that treating periodontitis reduces HbA1c by approximately 0.4 per cent, which means your dentist is affecting a number your GP is managing.

Does treating my gums protect my heart?

Not on the evidence. The association between periodontitis and cardiovascular disease is consistent, but the two share so many risk factors — smoking, diabetes, obesity, age, disadvantage — that adjusting for them weakens it considerably, and there is no good evidence that treating gum disease reduces cardiovascular events. Treat gum disease because it destroys the bone holding your teeth in. That is a sufficient reason, and it is one we can actually stand behind.

My mouth feels fine. Could I still have gum disease?

Yes, and that is the uncomfortable part of everything above. The peer-reviewed description is blunt: "In the early stages, the condition is typically asymptomatic; it is not usually painful, and many patients are unaware until the condition has progressed enough to result in tooth mobility." It is also not something anyone can settle by looking — "‘pocketing’ is not evident on simple visual inspection, and assessment using a periodontal probe is essential". And it is not rare: severe periodontitis, the kind that threatens whether you keep your teeth, affects 10 to 15 per cent of adults in most populations studied, with moderate periodontitis at 40 to 60 per cent — described in the same review as "a highly prevalent, but largely hidden, chronic inflammatory disease". So the honest answer to "how would I know" is that you would not, and a measurement is what settles it. See What is periodontal disease?

If I already have it, can it be reversed?

Partly, and the distinction decides how urgently the timing matters. Gingivitis — inflammation confined to the gum — is reversible with good oral hygiene. Periodontitis is not. Once the inflammation extends past the gum and destroys the collagen fibres of the periodontal ligament and the bone around the tooth, "the tissue destruction that occurs is largely irreversible", and treatment aims at stopping further loss rather than regrowing what has gone. Periodontitis is also described as slowly progressing, which cuts both ways: you have time, but the clock only runs in one direction. What the treatment involves is set out in Do I need a deeper cleaning?

Which of these risk factors can I actually change?

Smoking, glycaemic control and weight — and one you may not expect, your medication list. Smoking "significantly increases risk for periodontitis and severity of the condition" and is the largest modifiable factor of the three. Obesity is associated too, though much more weakly: the meta-analysis figure is an odds ratio of 1.35 (95% CI 1.23 to 1.47), and adults with a BMI of 30 or more carried a significantly increased risk compared with a BMI of 18.5 to 24.9 — an effect the authors suggest is mediated by insulin resistance rather than by weight as such. Several commonly prescribed drugs also cause gum overgrowth that makes plaque harder to control; the ones named in the literature are some calcium channel blockers, phenytoin and ciclosporin. None of that is a reason to stop a prescribed medicine. All of it is a reason to tell your dentist what you take.

Practical details

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