<s>[INST] I used braces 8 years ago and I use retainers to sleep only. Last week I went to the dentist because I feel a snap when I close and open my mouth.The Dentist told me that I grind my teeth and he suggest me to use a night guard, and change one of the retainers. He told me that the snap will stop when I use the night guard. My question is should I use the night guard or continuing with the old retainers?cm [/INST] Hi. Welcome to Chat Doctor . I have gone through your query and can understand your concerns. As per your complaint in case if you feel a snap while opening and closing the mouth, it seems to be probably related to jaw joint known as Temporomandibular joint and teeth grinding habit or bruise seems to be a most probable cause in this case. Bruxism can lead to continuous pressure over the jaw joints as well as it can cause dislocation of the soft cushion known as Articular disc present between the bony ends of the jaw joint. Any disturbance in the function can lead to snapping or clicking sound. If you are diagnosed with having bruise then wearing night guards is a beneficial treatment as it will cover the teeth surfaces also that the retainers will not do.Therefore, you should get a custom-made retainers fabricated that you should wear every night while sleeping to avoid bruise. Hope this information helps. Thanks and regards. Chat Doctor.  </s>