The short answer is, no. You are not alone in thinking this as this is the number one question asked during Botox Consultations. Here’s how this works. The muscles that allow you to clench and grind, which contribute to most people’s TMJ pain, are not the same muscles that allow you smile.
The two large muscles in your face, the masseter and temporalis, allow you to close your mouth. During clenching and grinding, too much use and strength is given to those muscles allowing them to enlarge and become bulky. Just like a body builder bulks up when exercising, these muscles grow and strengthen with overuse.
When done properly, injections in these muscles do not change you ability to smile, chew, talk, swallow, etc.
The power and strength that is given to these muscles during your clenching and grinding is now decreased. The injectables do not allow the muscle to overwork and therefore stop the clenching and grinding. Over the course of a year’s treatment (this is about 3 treatments spaced out by 4 months with no interruptions in dosage) you can notice the muscle slenderizing and appearing less bulky.
This is because we have not allowed the muscle to overwork again. Going back to the body builder analogy, since the muscle hasn’t been able to overwork in a year, the muscle gets smaller and less powerful. When it comes to clenching and grinding, this is our goal.