An orthodontic appliance includes a telescopic assembly with an end tube and a telescopic member. A distal connector secured to the end tube at a generally distal end of the telescopic assembly. An end cap engages the distal end of the end tube. A spring is secured to the end cap and extends coaxially within the cover and the end tube. The spring is configured to impart a biasing force against the distal end of the telescopic member.