Basic Info

Over the past twenty years, treatment options for jaw clenching and grinding have evolved. Masseter hypertrophy and bruxism can cause the lower face to appear wider, wear down teeth, lead to headaches, and disrupt sleep. In Hobart, an increasing number of adults now seek help for clenching during the day or grinding at night. Instead of using splints or surgery, botulinum toxin type A offers a simpler option. It works by relaxing the jaw muscle and can also soften the shape of the lower face.

What Is Masseter Hypertrophy?

Masseter hypertrophy refers to the condition where the main chewing muscle in the jaw becomes thicker than normal. This muscle sits at the back corner of the jaw. It can be felt or seen on an ultrasound as bulkier than average and sometimes makes the jaw look square. It may also ache during chewing. The change typically accumulates over time through repeated use. Chewing gum frequently, playing wind instruments, or having an uneven bite can cause the muscles to grow. It’s seen in both men and women, though more women between twenty-five and forty tend to ask about it, usually because they want to slim the lower face.

How Does Bruxism Cause This?

Bruxism refers to the clenching or grinding of the teeth, often occurring during sleep. It’s considered a movement issue. In sleep studies, the masseter muscle activates in short bursts, sometimes dozens of times each night. This constant strain causes the muscle to grow larger. Daytime clenching, often associated with stress, works similarly but tends to involve gentler pressure that is held for longer periods. Both types can lead to joint pain and morning headaches.

How Does Botox Reduce Masseter Size?

Botulinum toxin reduces masseter size by blocking the nerve signals that trigger muscle contraction. When the muscle is used less, it gradually shrinks in size. This process begins when the toxin stops the release of acetylcholine, the chemical that activates muscle movement.

The product is injected into the thickest part of the masseter, and its spread depends on factors like dilution and needle size. Care is taken to target the muscle sufficiently without affecting the nearby muscles that lift the lip. Some clinicians use ultrasound or rely on surface anatomy to guide accurate placement.

How Much Is Used

Earlier approaches used forty to sixty units per side. In Australia, cosmetic doses range from 15 to 30 units per side. For bruxism with pain, up to fifty units might be used. Starting with a lower dose helps avoid tiredness when chewing and allows for a small top-up later if needed. A recent systematic review of nine randomised clinical trials found that BoNT-A reduced bruxism events and pain severity, with some studies showing a decrease in pain scores from 7.1 to 0.2 and a decrease in clenching episodes from 4.97 to 1.70 per hour. In a Hobart review of eighty patients, twenty units, split into four areas, worked well for most people.

When It Starts Working

Muscle activity begins to slow after two to three days. In one week, the area feels softer. After about eight weeks, scans show that the muscle is approximately thirty per cent smaller. Bite strength also decreases, and the jawline appears less pronounced. Most people also experience less jaw pain. The effects typically wear off after four to six months; however, with repeat treatments, sessions may be spaced out to occur every nine months.

How Effective Is Botox for Bruxism Pain?

Studies show that Botox can reduce clenching episodes by half and lower morning jaw pain by a similar amount three months after treatment.

What Studies Show

A double-masked, randomised clinical trial conducted in Seoul evaluated the effect of botulinum toxin type A on nocturnal bruxism. Twelve participants were assigned to receive either botulinum toxin injections or a saline placebo into the masseter muscles. Electromyographic recordings taken during sleep revealed a significant reduction in bruxism events in the masseter group over 12 weeks. The temporalis muscle, used as a control, did not show significant changes. Participants who received botulinum toxin also reported improvements in bruxism-related symptoms. The findings suggest that botulinum toxin reduces clenching by limiting muscle activity, rather than affecting central nervous system pathways.

What to Expect During and After Treatment

The person receiving treatment usually sits upright and clenches lightly while the clinician identifies the firmest part of the masseter muscle. Small injections are placed directly into the muscle, and a visible bump may confirm correct placement. An ice pack or a vibration tool can be used to reduce discomfort. The full appointment typically takes under fifteen minutes. Aftercare includes avoiding hard chewing for two days and taking paracetamol if any soreness occurs.

Some individuals first seek help for facial slimming and later report relief from clenching or jaw tension. Others attend for pain management and also notice a softer lower face. Treatment may address both concerns. Changes in jaw shape are usually visible between weeks eight and twelve and gradually fade by six months. Ongoing sessions may be recommended every four to six months to maintain the effect.

Short-term effects can include swelling, minor discomfort, or temporary chewing fatigue. Rarely, nearby muscles may be affected, which can cause a mild change in smile that typically resolves. Some individuals experience dry mouth, which usually improves without intervention. Muscle function involved in regular chewing is generally maintained through compensation by surrounding muscles.

Practical Considerations and Long-Term Outlook

Jaw clenching and grinding often occur alongside other issues such as an uneven bite, missing molars, or breathing disturbances during sleep. Botulinum toxin is typically most effective when part of a broader plan that may include dental work, splints, physiotherapy, or sleep-related care. If one side of the jaw is overused due to pain or missing teeth, that should be addressed first. Coordinated care between injectors, dentists, and jaw specialists helps ensure a balanced approach.

This treatment may be suitable for individuals with visibly enlarged masseter muscles, morning jaw discomfort, or signs of tooth wear resulting from clenching. It isn’t appropriate for everyone. People with certain nerve or muscle conditions, those who are pregnant, or those on medications that increase the risk of weakness should be assessed carefully. Baseline photographs or imaging can help monitor outcomes over time.

With consistent maintenance, the effects of treatment can help reduce strain on the jaw and teeth. Some individuals in professions that involve heavy jaw use, such as teaching or playing wind instruments, may benefit from ongoing care. Treatment plans can be adjusted, paused, or modified as needed, depending on personal goals and changes over time.

Clinical Practice and Future Directions in Hobart

In Hobart, clinicians encounter a diverse range of individuals seeking treatment for jaw clenching or facial muscle issues. Some present during high-stress work periods, while others are recovering from jaw injury or have not responded to splint therapy alone. Referrals often come from dentists when additional muscle-based support is needed. Doses and treatment intervals are tailored to each person, depending on symptoms and treatment goals. While botulinum toxin does not address underlying causes, such as stress or airway issues, it may alleviate discomfort enough to support other therapies. In some cases, patients are referred for support such as stress management or movement-based therapy.

New tools are making treatment planning more precise. Facial scanning can track changes in jaw volume before and after treatment, and custom dental splints can be designed to align with muscle changes, improving comfort and function. Research continues to explore longer-lasting formulations and more targeted approaches, including techniques that map muscle activity. These developments may influence how future care is delivered and supported.

In Australia, Botox is a prescription-only medicine that can only be administered by trained medical professionals. Regulations require that public communication about treatment remains factual and balanced. Clinics must clearly present both benefits and risks and avoid language that could be perceived as promotional.