An occlusal splint, also known as a nightguard or dental splint, is a custom-made oral appliance used to protect the teeth and jaw during sleep. It is typically made from acrylic material and fits over either the upper or lower teeth, creating a cushioning barrier between the upper and lower dental arches.

The primary purpose of an occlusal splint is to address issues related to bruxism, a condition where a person unconsciously grinds or clenches their teeth during sleep. Bruxism can lead to several dental problems, including tooth wear, jaw pain, headaches, and even temporomandibular joint disorders (TMJ).