CATEGORY 64 AUSTRALASIAN DENTIST The aesthetic industry continues to evolve rapidly, and as more dental practitioners incorporate facial injectables into their practice, a deep understanding of the science behind botulinum toxin formulations has become essential. Although treatment outcomes may appear comparable to patients, the biological behaviour, composition, and long-term effects of the seven available botulinum toxin brands differ in significant ways that every practitioner should understand. At Dermal Distinction Academy, we believe that true aesthetic mastery begins with scientific understanding. Knowing how each toxin works – and how the body may respond to it over time – enables injectors to make safe, informed, and effective decisions for every patient. This topic is personal for me. I recently reviewed a patient who had undergone masseter treatment by a wellknown dental practitioner. It became evident that the practitioner did not fully understand the pharmacological nuances of botulinum toxin. Unfortunately, the patient had been rendered completely immune to all botulinum toxin treatments due to high dosing at frequent intervals using a formulation known for antibody production. So, let’s break it down. How Botulinum Toxin works Botulinum toxin type A (BoNT-A) is a neurotoxin produced by Clostridium botulinum, a bacterium found in nature. In controlled doses, it acts as a neuromodulator, temporarily blocking communication between nerves and muscles. In its simplest form, the process occurs in three stages: 1. Binding – The toxin binds to presynaptic cholinergic nerve terminals at the neuromuscular junction. 2. Internalisation – The toxin is absorbed into the nerve cell through endocytosis. 3. Blocking neurotransmission – The light chain cleaves SNAP-25, a key protein required for acetylcholine release. Without acetylcholine, the muscle cannot contract – resulting in the temporary relaxation that underpins aesthetic treatments. This effect is dose-dependent and reversible. Over time, new nerve terminals regenerate, restoring neuromuscular communication. This is why results typically wear off after three to four months, although duration varies depending on dose, product, and patient metabolism. Clinical implications for practitioners For practitioners, muscle relaxants offer immense therapeutic and aesthetic potential. Beyond smoothing frown lines or softening the masseter, botulinum toxin can help manage bruxism, temporomandibular dysfunction, gummy smiles, and facial asymmetry. However, not all formulations behave identically, and understanding their subtle differences helps optimise results while maintaining patient safety and compliance with scope of practice. Comparing the brands: What’s inside the vial? The table below outlines key differences among the seven botulinum toxin brands currently available in Australia – Botox, Dysport, Xeomin, Letybo, Nuceiva, Relfydess, and Daxxify. While each contains a form of botulinum toxin type A, their complexing proteins, molecular weights, excipients, and manufacturing processes differ, influencing diffusion, onset, duration, and risk of antibody formation. It’s also important to note that Dysport is not available for dentists to purchase directly through Galderma, due to a global agreement by its parent company, IPSEN, which restricts distribution to dental practitioners. Dentists should remain mindful of this limitation and consider supporting pharmaceutical partners that actively recognise and support the dental profession. Purified Vs complexed formulations and immunity The most significant differentiator among brands is whether the formulation contains complexing proteins or consists of a pure neurotoxin. X Complexed toxins – such as Botox, Dysport, Letybo, and Nuceiva – include accessory proteins that naturally occur during bacterial fermentation. These proteins remain bound to the molecule and do not contribute to therapeutic action. X Purified toxins – including Xeomin, CLINICAL Choosing the right Botulinum Toxin: Understanding the science behind the brands to avoid immunity Dr Giulia D’Anna By Dr Giulia D’Anna, Dermal Distinction Academy Brand Manufacturer Active Molecule Molecular Additives Storage Weight Botox Allergan OnabotulinumtoxinA 900 kDa NaCl, complexing 2–8°C proteins Dysport Ipsen AbobotulinumtoxinA 500-900 kDa Lactose, Bacterial 2–8°C (Galderma) Flagellin, complexing proteins Xeomin Merz IncobotulinumtoxinA 150 kDa Sucrose Room temp Letybo Hugel LetibotulinumtoxinA 900 kDa NaCl, complexing 2–8°C proteins Nuceiva Evolus PrabotulinumtoxinA 900 kDa NaCl, complexing 2–8°C proteins Relfydes s Galderma RelabotulinumtoxinA 150 kDa Polysorbate 80, Water 2–8°C Daxxify Revance DaxibotulinumtoxinA 150 kDa Peptide & Polysorbate 20 Room temp
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