Abstract: An intraoral orthosis having a first shell and a second shell, the shells being connected together by an adjustable connection device. The adjustable connection device has two notched tabs that are arranged respectively on either side of one of the shells, each notched tab co-operating in adjustable manner with a respective adjustment housing, arranged correspondingly on either side of the other of the shells, each notched tab having adjustment teeth to adjust the position of the shells one relative to the other, and locking housings to lock the position. The locking housings are oriented transversally relative to the adjustment teeth.