If you have been told that you have a closed locked by a healthcare professional then the gentle jaw will not help. A closed locked, which is clinically known as anterior disc displacement without reduction, is a mechanical issue that will not be resolved by stretching. A closed locked means the neck of the jaw, which is called the condyle, is blocked by the back part of the disc from being able to get onto the disc. When the disc is blocking the condyle it means the opening is extremely limited compared to before the locking occurred and if you try to open wider, the jaw does not budge at all. When the condyle is on the disc, you might hear a click when opening, and you should be able to open further after you hear the click. However, the opening can still be limited because the muscles are sore and/or injured from overuse due to clenching, grinding, chewing gum, stress, etc. If you feel that you are able to open but it hurts, then the issue is likely muscular and the gentle jaw can help. If you feel that when you try to open it feels like it would be impossible to open even 1 mm more and your opening is much less than normal, then it is likely a disc issue and the gentle jaw will not help and you should see a dentist with specialty training on how to unlock the joint.