Stacking firewood, wrestling with a stuck bolt, or pushing through a long task can all find people with their teeth jammed together. Clenching is that firm, held contact between the upper and lower teeth, generally without the rubbing motion of grinding. It isn't limited to hard work. It can turn up during quiet concentration, during sleep, or both, and often you only realise afterward, when the jaw is stiff or a tooth feels bruised.
A tired jaw doesn't automatically mean clenching, though. Dental problems, the jaw joint and the muscles of chewing can all produce similar aches, and they sometimes overlap. Examining first keeps you from treating the wrong thing. We look at your particular pattern, check for damage or another condition that calls for its own care, and then discuss practical ways to lessen the strain on your teeth and protect them when it's appropriate.
Come with whatever you've noticed, even if it doesn't follow a neat pattern. If you have a guard, bring it along, and tell us about medicines, sleep concerns and previous advice. An appliance isn't a given, and no device can promise to switch clenching off for good.