Hello, Thanks for your query. Trismus, or lockjaw, refers to reduced opening of the jaws caused by spasm of the muscles of mastication, or may generally refer to all causes of limited mouth opening. It is a common problem with a variety of causes, and may interfere with eating, speech, oral hygiene, and could alter facial appearance. Treatment requires treating the underlying condition with dental treatments, physical therapy, and passive range of motion devices. Additionally, control of symptoms with pain medications (NSAIDs), muscle relaxants, and warm compresses may be used. I do hope that you have found something helpful and I will be glad to answer any further query. Take care