Abstract: An oral appliance having upper and lower channel elements attached, respectively, to upper and lower bite blocks. The two channel elements are oriented at a right angle with respect to each other. One of the channel elements carries a removable insert having an array of adjustment holes. A removable coupling member has a support rod with an anchor piece and anchor pin at one of its ends. The anchor piece is received by the channel element carrying the insert, while the anchor pin is received by one of the insert's adjustment holes. A base at the other end of the support rod is received by the other channel element, so that the coupling member may releasably connect the two channel elements together.