Aesthetic Medicine

Bruxism: when botulinum toxin helps the jaw to rest.

Do you wake up with a tight jaw, headaches or sensitive teeth? It may be bruxism — and, in selected cases, botulinum toxin is one of the tools to ease the force of the chewing muscles.

Helder Moreira
Helder Moreira  ·  19 October 2026  ·  2 min de leitura
Perfil de uma mulher com a linha do maxilar em destaque

In short

What bruxism is

Bruxism is repetitive activity of the chewing muscles, with clenching or grinding of the teeth. It can happen during sleep or while awake — often linked to stress, concentration or sleep disturbances — and is not always noticed by the person themselves1.

Common signs

01

Tight jaw

Pain or tiredness in the face muscles on waking.

02

Worn teeth

Wear, cracks or tooth sensitivity.

03

Headache

Especially at the temples, in the morning.

04

Wider lower face

An enlarged masseter that widens the lower face4.

How botulinum toxin works

Small doses injected into the masseter (and sometimes the temporalis) temporarily relax the muscle. Clenching force decreases and, in several studies, pain and the frequency of episodes were reduced, with a good safety profile2,3. When the muscle is enlarged, the facial contour can also soften over the following weeks4.

Usual timeline2,5

Day 0

Assessment and treatment

Medical assessment and a few injections on each side.

1–2 weeks

Less tension

Clenching loses force and pain usually eases.

4–8 weeks

Contour

If the masseter was enlarged, the face may slim.

3–6 months

Review

The effect fades gradually; you decide whether and when to repeat.

Myths and facts

✕ Myth

“I won’t be able to chew.”

✓ Fact

The dose reduces excessive force, not function. Chewing and speaking stay normal3.

✕ Myth

“It replaces the night guard.”

✓ Fact

No. The guard protects the teeth; the toxin acts on the muscle. They often complement each other.

For bruxism, botulinum toxin is an off-label use, outside the indications approved in the medicine’s summary of product characteristics. It is only offered after a medical assessment, discussing alternatives, and with informed consent5. It is not suitable during pregnancy, breastfeeding or with neuromuscular diseases.

A plan made for you.

Every face and every skin is different. Book an assessment: we review your case and design a personalised treatment plan with you, with realistic goals.

Helder Moreira

Written by

Helder Moreira

Physician accredited in Aesthetic Medicine · Portuguese Medical Association (Ordem dos Médicos) — licence no. 55532

Patient information

The procedures and treatments mentioned in this article require a prior individual medical assessment and, in some cases, a medical prescription. Indications, results and their duration vary from person to person and cannot be guaranteed. This article is for information only and does not replace a medical consultation.

For more information contact Facelab, Lda. on +351 961 023 229, by email at geral@facelab.pt, or visit www.facelab.pt.

  • FACELAB Albufeira — Rua do Estádio, Quinta da Bela Vista, Lote 2, 8200-127 Albufeira · ERS Registration Certificate: E172446 · Operating licence: 24619/2024
  • FACELAB Faro — Rua da PSP, n.º 22, 8000-408 Faro · ERS Registration Certificate: E180121 · Operating licence: 26536/2025

References

  1. Lobbezoo F, Ahlberg J, Raphael KG, et al. International consensus on the assessment of bruxism: report of a work in progress. J Oral Rehabil. 2018;45(11):837–844.
  2. Fernández-Núñez T, Amghar-Maach S, Gay-Escoda C. Efficacy of botulinum toxin in the treatment of bruxism: systematic review. Med Oral Patol Oral Cir Bucal. 2019;24(4):e416–e424.
  3. Long H, Liao Z, Wang Y, Liao L, Lai W. Efficacy of botulinum toxins on bruxism: an evidence-based review. Int Dent J. 2012;62(1):1–5.
  4. Kim NH, Chung JH, Park RH, Park JB. The use of botulinum toxin type A in aesthetic mandibular contouring. Plast Reconstr Surg. 2005;115(3):919–930.
  5. INFARMED, I.P. Resumo das Características do Medicamento (RCM) das toxinas botulínicas tipo A autorizadas em Portugal. Base de dados INFOMED.
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Helder Moreira