Thank you for your question. Botox or Dysport can be a very effective way to contour the jaw line by reducing the masseter shadow through the outer jaw skin. In addition, it can reduce symptoms of jaw clenching or grinding of teeth at night time. This is an advanced technique that requires a strong understanding of the underlying anatomy. Some side effects can results in some very unintented effects. This can include affecting the smile due to diffusion of the Botox into neighboring smile muscles. Over treatment can also overweaken your jaw muscles making it harder to chew food and causes your jaw muscles to relax too much when you sleep.The injection technique does vary by physical exam and the goals of the treatment. I ask my patients to place their hands along the sides of their face over their masseter muscles and clench on/off so they can feel the masseter muscles bouncing against their hands. I also ask them to repeat this at home in a couple weeks time to compare so they can see the effects of the masseter reduction. Facial contouring goals may change the injection sites themselves to affect different portions of the masseter as well as the dose. The strength of the masseters can be felt by palpation and also helps me to determine dosing. In general, I start with 15- 25 units of Botox (OR 50-75 units of Dysport) per side for most patients. If they have very strong masseters, then I may increase the dose, but more commonly ask them to return in three weeks for a touch up. Once you get the desired result, I let patients know that future treatments may require less to maintain the look or the jaw clenching symptoms, especially if they get treated as soon as they notice the symptoms return. This can be as soon as three to four months, but in some cases, patients report that it lasts six months or more. I find it depends on the dose we use and how many times we have done the procedure as the duration may lengthen for patients that repeat it regularly.
