An orthodontic expansion device (100, 300), comprising: a first lateral wing (102a, 302a) and a second lateral wing (102b, 302b) opposite one another, wherein the first lateral wing and the second lateral wing each comprise a molar band (108a, 108b) shaped to receive a molar of a patient, and a palate frame (110a, 110b) extending obliquely from the molar band, the palate frame being shaped to lie against the patient's palate; and a hinge arm extending from the palate frame of the first lateral wing; a tensioning assembly disposed between the first and second lateral wings, wherein the tensioning assembly comprises: a first end pivotably attached to the hinge arm of the first lateral wing; and a second end detachably attached to the second lateral wing; a piston (114, 314) disposed between the first end and the second end; an adjustment rod (112, 312) comprising a first rod end including a thread that engages a corresponding thread extending along an interior bore of the piston, such that the adjustment rod is at least partially threaded into the interior bore of the piston; and a spring, wherein the adjustment rod retains the piston against the spring to maintain the first lateral wing and the second lateral wing in an outwardly tensioned relationship away from each other. a first lateral wing (102a, 302a) and a second lateral wing (102b, 302b) opposite one another, wherein the first lateral wing and the second lateral wing each comprise a molar band (108a, 108b) shaped to receive a molar of a patient, and a palate frame (110a, 110b) extending obliquely from the molar band, the palate frame being shaped to lie against the patient's palate; and a molar band (108a, 108b) shaped to receive a molar of a patient, and a palate frame (110a, 110b) extending obliquely from the molar band, the palate frame being shaped to lie against the patient's palate; and a hinge arm extending from the palate frame of the first lateral wing; a tensioning assembly disposed between the first and second lateral wings, wherein the tensioning assembly comprises: a first end pivotably attached to the hinge arm of the first lateral wing; and a second end detachably attached to the second lateral wing; a piston (114, 314) disposed between the first end and the second end; an adjustment rod (112, 312) comprising a first rod end including a thread that engages a corresponding thread extending along an interior bore of the piston, such that the adjustment rod is at least partially threaded into the interior bore of the piston; and a spring, wherein the adjustment rod retains the piston against the spring to maintain the first lateral wing and the second lateral wing in an outwardly tensioned relationship away from each other. a first end pivotably attached to the hinge arm of the first lateral wing; and a second end detachably attached to the second lateral wing; a piston (114, 314) disposed between the first end and the second end; an adjustment rod (112, 312) comprising a first rod end including a thread that engages a corresponding thread extending along an interior bore of the piston, such that the adjustment rod is at least partially threaded into the interior bore of the piston; and a spring, wherein the adjustment rod retains the piston against the spring to maintain the first lateral wing and the second lateral wing in an outwardly tensioned relationship away from each other.