According to PainScience.com, Temporomandibular joint syndrome is a failure of jaw joint function, mostly pain and/or limited movement, and massage is a very simple way to ease the tension!
Don't expect a chilled out massage session! Your neck, shoulders, inner and outer jaw muscles will be worked on, and since the majority of jaw muscles are more easily accessed within the mouth your therapist will use sterile gloves to massage the jaw muscles around your gums and on the floor of your mouth. This can be an odd sensation the first time, but your therapist will talk you though the whole process and provide plenty of breaks. Check out this video on YouTube to familiarize yourself with the techniques used: TMJ intra oral massage video.