This clinical trial is focused on studying the effects of a treatment for temporomandibular disorder (TMD), a condition that affects the jaw joint and muscles controlling jaw movement. The treatment being tested is an injection of Clostridium botulinum neurotoxin type A, commonly known as Botulinumtoxin A, which is a muscle relaxant. This study aims to determine if these injections can effectively reduce muscle pain in patients with TMD and whether the effectiveness depends on the dose given.

Participants in the study will receive injections of Botulinumtoxin A in specific jaw muscles, namely the masseter and temporal muscles, which are involved in chewing and jaw movement. The study will observe changes in pain levels and assess if different doses of the treatment have varying effects on pain relief. Additionally, the study will look at how the treatment impacts the quality of life, jaw function, and any psychosocial changes in participants.

The study will be conducted over a period, with participants being monitored for changes in their condition. The primary focus is on how pain levels change and whether the dose of Botulinumtoxin A matters for pain relief. Secondary observations will include improvements in quality of life and jaw function, as well as any psychosocial changes experienced by the participants. The study is expected to provide valuable insights into the treatment of myogenous TMD, which is a type of TMD caused by muscle issues.