People often use teeth grinding as a catch-all term for bruxism but clenching and grinding are technically distinct behaviors with different mechanisms, different damage patterns, and some different management implications.
Grinding
Grinding involves lateral movement of the jaw with the teeth in contact. The upper and lower teeth rub against each other in side-to-side or front-to-back motions. This is what produces the audible sound that bed partners sometimes report. Grinding creates friction-based wear across the tooth surfaces. The chewing surfaces of back teeth develop a characteristic flat appearance and the edges of front teeth can wear to translucent chisel-like edges. The wear pattern from grinding is often horizontal. The teeth look shorter and flatter than they should.
Clenching
Clenching involves sustained intense vertical pressure. The teeth are held in contact without lateral movement with the jaw muscles contracting forcefully. Clenching is silent. There is no rubbing sound which is one reason it often goes undetected longer than grinding. The damage from clenching is different: rather than abrasion of the tooth surfaces it produces excessive compressive forces that stress the teeth, the periodontal ligament, and the jaw joints. Clenching can cause tooth cracking, jaw muscle pain, TMJ loading and pain, and headaches particularly temporal headaches upon waking.
Management: what helps each type
Night guards protect against both grinding-related abrasion and clenching-related fracture. For clenching specifically hard acrylic guards are generally preferred over soft athletic-type guards. Soft guards can actually encourage clenching in some patients by providing something to clench against. Botulinum toxin injections into the masseter muscles reduce the force of both clenching and grinding. Awake bruxism is addressed through awareness-based approaches identifying situations where it occurs and consciously releasing jaw tension. For broader detail on bruxism including recovery see our bruxism guide and our sleep grinding article.
Educational content. Suspected bruxism warrants evaluation. Dentists can identify wear patterns and recommend appropriate protective measures.
