1. What is botulinum toxin? Is it toxic?
Botulinum toxin isn't as frightening as its name suggests. Many beauty clinics refer to it as "biological wrinkle removal" or "genetic wrinkle removal" to alleviate public apprehension. As a biological product, it can be mass-produced through genetic engineering. Due to its nerve-blocking properties, it's widely used in neurology, ophthalmology, plastic surgery, and cosmetic procedures. Current application doses are merely one percent of its maximum safe level, making it highly secure.
2. How long has Botox been used?
Only products that stand the test of time prove their worth. Botox injections for cosmetic purposes have been in use for over 20 years.In 1986, while treating blepharospasm with botulinum toxin, the Canadian Carruther couple unexpectedly discovered its remarkable wrinkle-reducing effects. Subsequently, they applied botulinum toxin to treat forehead lines, glabellar lines, and crow's feet. After a series of trials, they first reported these findings in 1992. The Carruther couple thus became the inventors and pioneers of this technique.
3. Why treat masseter hypertrophy with botulinum toxin instead of direct muscle resection?
Women often seek facial contouring to achieve an oval face shape, frequently due to prominent jaw angles. Tens of thousands of mandibular angle osteotomies are performed annually. Over 90% of these patients also have benign masseter hypertrophy and desire simultaneous reduction.However, during surgery, it is difficult to accurately control the extent and depth of muscle resection. This not only yields suboptimal results but also increases the risk of complications such as bleeding, hematoma formation, infection, facial asymmetry, facial nerve paralysis, lockjaw, and prolonged muscle spasm.
Given that the procedure primarily involves masseter resection—which carries risks including trismus, asymmetry due to unpredictable resection volume, and potential damage to facial nerve branches—some Western scholars shifted their research focus to pharmacological treatments for "masseter hypertrophy."In 1994, Smyth et al. reported their experience using botulinum toxin to treat bilateral masseter hypertrophy, hailing it as a revolutionary new approach. Smyth recommended adopting this technique as the standard treatment for "masseter hypertrophy."Botulinum toxin injections induce atrophy and reduction of the masseter muscle through denervation, achieving more thorough treatment and resolving this challenge. This approach has significantly enhanced patient satisfaction and greatly increased the number of individuals seeking treatment. Combining botulinum toxin injections with mandibular angle surgery has yielded excellent results for treating a round face.Combining facial liposuction, zygomatic bone reduction, and narrowing procedures can achieve substantial improvement in a round face. 4. How is botulinum toxin administered? Typically, 1–2 injection sites are selected per side. Injections should be administered as slowly as possible. No local massage or special post-injection care is required; normal chewing motion allows the solution to gradually diffuse within the muscle tissue.
5. When does Type A botulinum toxin take effect? How long does the effect last?
Two weeks after Type A botulinum toxin injection into the masseter muscle, patients may notice reduced chewing strength during forceful chewing. The masseter muscle shows no obvious bulging or fatigue, and palpation reveals no significant contraction.Muscle atrophy and facial contour changes are typically observable one month post-injection. Effects generally persist for six months to one year.
6. What adverse reactions may occur?
As an intramuscular injection, botulinum toxin exhibits minimal significant side effects, offering advantages over traditional surgical methods.Local adverse reactions after botulinum toxin type A injection primarily include excessive weakness of the masseter muscle and corresponding symptoms caused by the toxin's diffusion into adjacent muscle tissue. These clinical manifestations correlate with the injection site and dosage administered. Some patients may experience fever, discomfort, or fatigue following injection. Generally, these symptoms are transient and resolve spontaneously within several weeks.
7. Will the effects recur after treatment?
After botulinum toxin injection into the masseter muscle, the effect typically lasts about 6 to 8 months. Once the toxin wears off, the masseter muscle gradually regains its strength. However, with repeated injections, the duration of effect progressively increases. After 3–4 sessions, the effect generally lasts about one year. In a small number of individuals, the masseter muscle effect may persist even without further injections. Botulinum toxin can be re-injected repeatedly without causing toxin accumulation.
8. What other comprehensive treatments are available for a round face?
Beyond Botox injections and mandibular angle osteotomy, options include facial liposuction, zygomatic bone reduction, and width reduction. Combining these treatments can significantly improve a round face.