Jaw can also be “rusty”? Many people usually encounter this situation in daily life: suddenly open your mouth wide, the jaw is like rust, can no longer be closed, strong closure, the joint in front of the ear pain; or eating, talking, yawning, as long as the jaw moves, the joint in front of the ear will also be like rust, a click sound, making people very uncomfortable. In fact, the crux of the problem lies in the TMJ “rusting”. The TMJ is a sliding joint and synovial fluid is an important lubricant. When the synovial fluid decreases or disappears, the joint will become “rusty”. Therefore, the injection of hyaluronic acid gel or medical chitosan into the TMJ as a “lubricant” is one of the current treatments for TMJ disorders. The injection of hyaluronic acid or chitosan into the patient’s joint cavity not only restores the viscoelasticity and physiological effects of the patient’s synovial fluid and improves the mobility of the patient’s joint, but also effectively relieves the pain in the patient’s joint area. According to our four-year statistics, of the approximately 10,000 temporomandibular joints injected, the incidence of significant pain (uncontrollable with oral pain medication) for longer than three days after injection is less than 5%, the incidence of neutral pain (controllable with oral pain medication) for longer than three days is less than 10%, and more than 85% have mild pain or no pain within two days. So why does it cause increased pain? 1, whether it is sodium hyaluronate gel or medical tylose, although there are state-approved intra-articular injection qualification, but no matter how to say or “foreign body”, there are always a very small number of sensitive organisms, can not tolerate and lead to pain; 2, there are some arthritis patients, after doing intra-articular injection, ” 3.We use intra-articular injection, “puncture injury” is inevitable, puncture will hurt the structure of the joint, especially for doctors with insufficient clinical experience, more likely to have multiple punctures and lead to pain; 4. Severe pain may be a necessary stage in the development of the disease. The development of the disease is sometimes unpredictable and the level of pain varies at different stages of the disease development, so sometimes pain may occur even without intra-articular injections. But it just so happens that when the injection is given, the pain also “arrives as expected”; 5, unknown causes, anything, including the occurrence of pain, has its own knowability and its unknowability, “the jade is missing to see the indomitable, the sword is broken to bless the real rigid. The open eyes do not see the heart, people are not easy to measure”. What if the rate of severe pain occurs? Generally speaking, it takes about two days to five days for the absorption of sodium hyaluronate gel or glucose injection, so most of the patients can be relieved after three or five days, at which time appropriate physical therapy can be done; if the pain continues to be severe for more than five days, joint cavity lavage can be done to flush out the unabsorbed medication inside, which can generally be significantly relieved after two or three days.