Hormones and Orthodontic Treatment: How Your Body Affects Your Braces

How do hormones influence bone metabolism during orthodontic treatment?

Orthodontic tooth movement depends on bone remodelling: the periodontal ligament responds to mechanical force by stimulating osteoclasts (cells that resorb bone) on the pressure side and osteoblasts (cells that deposit bone) on the tension side. Hormones regulate both of these cell populations. Oestrogen, testosterone, parathyroid hormone, thyroid hormone, and cortisol all influence the rate and efficiency of this process. When hormone levels are elevated or suppressed — due to puberty, pregnancy, menopause, or thyroid dysfunction — bone remodelling speeds up or slows down, with direct implications for how quickly and safely orthodontic forces can move teeth.

Puberty: the growth spurt and orthodontic timing

Puberty is the period of greatest bone plasticity. Rising levels of growth hormone and sex steroids during the adolescent growth spurt increase bone turnover and make teeth move more readily. This is why orthodontic treatment is traditionally timed to coincide with peak growth velocity — typically between ages 11 and 14 in girls and 12 to 15 in boys. Functional appliances that redirect jaw growth, such as twin blocks, are most effective during this window. Orthodontists use hand-wrist X-rays or cervical vertebral maturation staging to assess whether a patient is in their growth spurt and therefore an appropriate candidate for growth modification.

The menstrual cycle and pain sensitivity

Several studies have documented that pain sensitivity fluctuates during the menstrual cycle, with the perimenstrual phase associated with lower pain thresholds due to prostaglandin release. Some patients report that orthodontic adjustment appointments feel significantly more uncomfortable when they coincide with menstruation. While this is not a reason to delay appointments, patients who are aware of this pattern can plan adjustments for times in the cycle when they are likely to be less sensitive. Pre-emptive pain relief with paracetamol or ibuprofen at the time of adjustment is a practical strategy.

Pregnancy: safety, gingival changes, and timing

Orthodontic treatment is generally safe during pregnancy, but requires careful management. The elevated progesterone and oestrogen levels of pregnancy cause gingival hyperaemia and increased susceptibility to gingivitis — so maintaining meticulous oral hygiene is critical. X-rays should be minimised and, if required, shielded appropriately. Routine treatment can continue during the second trimester; the first trimester is a period of organogenesis and nausea, and the third trimester makes lengthy appointments uncomfortable. Many orthodontists prefer to complete treatment before pregnancy or manage conservatively during pregnancy, resuming active tooth movement postpartum. The main concern is not tooth movement itself but gingival health and the ability to maintain adequate oral hygiene throughout.

Menopause: slower tooth movement and higher relapse risk

After menopause, declining oestrogen levels reduce bone density and slow bone turnover. Both of these changes affect orthodontic treatment. Teeth may move more slowly, requiring longer treatment times. The reduced bone remodelling activity also increases the risk of orthodontic relapse after treatment ends, as the bone takes longer to consolidate in the new position. Post-menopausal patients have a higher incidence of root resorption with prolonged orthodontic force. Retention strategies need to be more robust — lifelong retainer wear is strongly advisable. Orthodontists should discuss these biological realities with older patients at the planning stage to set realistic expectations.

Thyroid conditions and bone metabolism

Both hypothyroidism and hyperthyroidism alter bone metabolism. Hypothyroidism slows bone turnover, which reduces the speed of tooth movement and may prolong treatment. Hyperthyroidism accelerates bone turnover, which can increase the risk of root resorption with orthodontic forces. Patients on thyroxine replacement therapy who are well-controlled should not experience significant problems, but uncontrolled thyroid disease can complicate treatment. If you have a thyroid condition, ensure it is well-managed before starting orthodontics and inform your orthodontist so they can adjust force levels and monitoring accordingly.

What hormonal information should you tell your orthodontist?

Patients should proactively disclose hormonal factors that may affect treatment. This includes pregnancy (confirmed or planned), thyroid conditions, use of hormonal contraceptives or hormone replacement therapy (HRT), whether they are perimenopausal, and any conditions affecting bone metabolism such as osteoporosis or steroid use. Orthodontists cannot tailor treatment appropriately without this information. HRT, for example, may partially offset the bone density loss of menopause and affect treatment planning decisions.

Adjusting treatment expectations

Understanding hormonal influences helps patients set realistic expectations. A teenager treated during peak growth will likely see faster movement than an adult patient. A post-menopausal patient may require a longer active phase and lifelong retention. A patient who is pregnant may need to pause active treatment during the first trimester or postpartum period for gingival management. These are not failures of treatment — they are predictable biological responses that a well-informed patient and clinician can plan for together.

Long-term retention implications

For any patient whose hormonal status affects bone metabolism — particularly post-menopausal women, patients with thyroid conditions, and patients with a history of osteoporosis — lifelong retainer wear is not optional; it is essential. The lower bone remodelling capacity means that consolidation of tooth positions after active treatment takes longer and is less complete. Fixed bonded retainers on both arches, combined with removable vacuum-formed retainers worn nightly, provide the most robust protection against relapse in these higher-risk groups.

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This guide is for general information only. It is not a diagnosis, treatment plan, or substitute for advice from a registered dentist or orthodontist.