Crepitus refers to joint noises, such as popping and cracking in the joints as tmj.
It can be quite disturbing & cause concern, particularly if it shows up suddenly. In most cases, these noises are not indicative of any underlying problem. Most joint crepitus, cracking and popping usually has a 'bark that is worse than its bite.' there is likely no concern. If any pain arises see a prosthodontist.