A fastener suitable for connecting two parts of a dental splint together in a prearranged or predetermined spatial relationship to treat a person suffering from a sleep disorder is described. In one form the fastener comprises a base member and a cover member arranged to define a cavity therebetween. A movable connector is located within the cavity, the movable connector interconnecting the two parts of the dental splint. The fastener has an adjustor movably connected to the connector such that the position of the connector is moved in response to movement of the adjustor by adjusting the position of the adjustor, the connector in the form of a hook moves the other part of the dental splint so as to reposition the jaws of a person being treated for the sleep disorder.