Can someone with thyroid disease have dental implants?

The thyroid gland is a gland that sits at the front of the neck and produces the hormones (T3 and T4) that set the body's metabolic rate. These hormones also affect the rate at which bone is continually broken down and rebuilt. That is why the question 'I have a thyroid condition, will my bone hold an implant?' is not out of place. But the question needs to be asked correctly: the issue is not the diagnosis itself, but whether the hormone levels are being kept stable with medicine.

Where the evidence is clearest is this: a systematic review published in 2022 assessed 11 of the studies it found in PubMed and Cochrane and concluded that people with thyroid disease can have implant treatment and that the rate at which implants stay in the mouth is similar to that in people without thyroid disease. The authors gave the level of evidence as B on the SORT scale, which means evidence of limited or inconsistent quality, and wrote plainly that larger, stronger studies are needed. In other words the answer is 'yes', but a 'yes' resting on a thin evidence base.

A study often cited for hypothyroidism is from Toronto. 27 women with hypothyroidism treated with medicine were compared with 29 people matched for age, sex and implant site. No difference emerged between the two groups in terms of implant loss. However, in the group with hypothyroidism, soft tissue problems were more common after the first surgery, and more bone loss around the implants was measured in the first year after loading. This detail adds the sentence 'it needs to be monitored closely' alongside the sentence 'there is no problem'.

There is also a finding in the opposite direction. A study in the USA that retrospectively examined 1,480 implants in 635 patients from X-ray records found the yearly bone loss around implants to be lower in those with hypothyroidism; the association held even after smokers and people with diabetes were excluded. The authors explain this by the slowing of bone breakdown in hypothyroidism. The study is observational and retrospective; reading the two studies together, there are no data showing that hypothyroidism poses a marked risk for implants.

With hyperthyroidism the picture is different and there is less evidence. Here, rather than studies on implants, two matters stand out in terms of general health. The first is bone: the NHS writes that an overactive thyroid can increase the risk of osteoporosis, which weakens the bones. The second is thyroid storm: MSD Manuals describes this as a life-threatening emergency of untreated or inadequately treated hyperthyroidism that can be triggered by infection, injury, surgery or stopping thyroid medicines. It is rare, but it is the reason hormones should be stable before planned surgery.

Severe, untreated hypothyroidism also has a rare emergency of its own: myxoedema coma. MSD Manuals writes that it can be triggered by infection, injury, surgery and sedative medicines that depress the brain; the NHS also notes that it is seen more often in older people. This is not a risk that applies to most patients who are stable on levothyroxine. But if the diagnosis is new, the medicine has just been started or sedation is planned, it is the reason for checking the levels beforehand.

In patients who have had radioactive iodine after thyroid cancer, the issue is saliva rather than bone. Because the salivary glands accumulate iodine, they are affected by radioactive iodine. In a review examining 38 studies, dry mouth was seen in about 60% of patients in the first 2 months after treatment and in about 17% after one year; inflammation of the salivary glands was also often reported. The American Thyroid Association also writes that loss of taste and dry mouth can be seen after thyroid cancer treatment.

Dry mouth matters for implants because saliva is the system that cleans and protects the mouth by itself. When saliva is reduced, plaque builds up more easily, the risk of decay and gum disease in the remaining teeth rises, and a removable denture also rubs more easily. This picture does not make implants impossible; but it requires the care plan, the frequency of check-ups and the cleaning tools to be chosen accordingly.

The distinction below is a framework. The final decision is made after your current test results, the medicines you take and the condition of your mouth have been assessed together; if necessary, the doctor who looks after your thyroid is consulted.

Safety is largely achieved through up-to-date information and the right timing. The steps below are the framework of standard preparation.

1. 1

   Know the emergency signs first

   Thyroid storm is a rare but urgent picture: a very fast heartbeat, a high temperature, severe agitation, confusion or loss of consciousness, yellowing of the skin and eyes. If these symptoms are present, you do not wait for a dental appointment; call 112 or go to the nearest A&E.

2. 2

   Current TSH and T4 results

   The NHS writes that in a thyroid assessment the levels of TSH (thyroid-stimulating hormone) and T4 (thyroxine) in the blood are checked. Bring your most recent test and its date; if the levels are old or the dose has changed recently, a new one may be asked for. If you take biotin (vitamin B7), say so; the NHS notes that biotin can affect thyroid tests.

3. 3

   A complete medicine list

   Levothyroxine, carbimazole, propylthiouracil, beta blockers; with their names and doses. Medicines other than thyroid ones matter too: the NHS writes that stomach medicines (such as omeprazole), antacids, calcium and iron supplements, and some blood pressure and heart medicines may not mix well with levothyroxine.

4. 4

   A discussion with the doctor who looks after your thyroid, if needed

   If the levels are borderline, the medicine has recently changed or uncontrolled hyperthyroidism is suspected, an endocrinology opinion is obtained before surgery. Whether a dose adjustment is needed is decided by that doctor, not the dentist.

5. 5

   The time of the medicine on the day of surgery

   The NHS recommends taking levothyroxine on an empty stomach, 30–60 minutes before breakfast, coffee or tea and other medicines. If you are asked to fast for sedation, ask in advance when to take your morning dose; do not skip the medicine on your own.

6. 6

   Saliva assessment if you have had radioactive iodine

   If you have dry mouth, a change in taste or swelling in the salivary glands during meals, say so. These findings directly affect the care plan, the frequency of check-ups and the cleaning tools.

7. 7

   Imaging and the plan

   The condition of the bone is assessed with a CBCT scan. If you send your test results, your medicine list and any images you have through the assessment form in advance, the dentist builds the plan on this information.

Thyroid disease does not narrow the options to any great extent; it affects the timing and the care plan more.

Most of the following are manageable matters in patients who are stable. Some are specific to an uncontrolled picture; we state the distinction under each item.

In a thyroid patient who is stable, healing does not proceed differently from other patients; the difference is keeping the medicine routine and monitoring the first year more closely.

1. The first days

   Carry on taking your thyroid medicine in the routine your doctor has told you. When you move to a soft diet, take care still to take levothyroxine on an empty stomach; do not take it at the same time as soup, milk or coffee.

2. The first week

   Swelling and tenderness should go down. A fever, increasing swelling or a bad taste in the mouth can suggest infection; if you are being treated for hyperthyroidism, reporting an infection early is all the more important.

3. The first months

   Checking the soft tissue and the bone around the implant. The study reporting more bone loss in the first year in patients with hypothyroidism makes X-ray follow-up in this period meaningful.

4. The long term

   Regular professional maintenance and daily interdental cleaning. If the dose of your thyroid medicine changes or a new thyroid treatment starts, let your dentist know as well.

Thyroid disease does not directly change the fee for implant treatment. What it affects is the preparation, the timing and the follow-up routine:

Additional tests and an endocrinology opinion

If there are no current TSH and T4 results or the levels are borderline, a new test and a doctor's opinion may be needed.

Treatment being postponed

If surgery is postponed in uncontrolled hyperthyroidism, the timetable changes; for patients who travel for treatment, this is an item that affects planning.

Care directed at dry mouth

If there is dryness after radioactive iodine, more frequent professional cleaning, fluoride application and saliva substitute products become part of the care item.

Whether an additional procedure is needed

If the condition of the bone proves insufficient on the CBCT scan, the extent of the plan changes; when anchorage can be achieved without bone grafting, this item shrinks.