Abstract: A thermoplastic vacuum formed active dental retainer and method of straightening teeth. The retainer of the invention is made by first making a plaster or other suitable model of the teeth and then forming a plastic overlay by means of vacuum forming a thin clear plastic material over the model. Secured to the surface of the oral cavity portion of the overlay is a tubular member which may either serve itself as a tensioning member or mount a wire spring-like tensioning member. The tubular member and tensioning member are positioned in such a manner as to be in proper alignment with the tooth to be straightened. A number of bends in the tubular member and the tensioning member allow for exertion of a force over a relatively long distance thus increasing the amount of work any given size wire can perform over what could be accomplished with a straight wire of the same size.

Abstract: The present invention encompasses a novel spring construction and a method of application of the spring in the field of orthodontics. A tension spring member is at least partially surrounded by a tension releasable component of larger diameter. The tension spring will normally be a coil spring adapted to be placed under tension between two points. The tension releasable component will normally comprise either a closed coil spring or an open coil spring. In either case, the tension releasable portion comprises an integral extension of the tension spring member and is designed to deform in response to a predetermined force thereby releasing the device from its tension exerting position. The orthodontic method of the invention comprises anchoring one end of the novel tensioning device to a tooth to be moved and the other end to an anchor point. The device is then placed under tension and the tension releasable means is used to hold one end of the device.

Abstract: An intra-oral orthodontic spring appliance is provided which consists of a metallic coil spring having an enlarged tension releasable means at one end which engages fixed spring mounting means in the mouth and a tail at the other end which engages suitable means on a tooth to be repositioned. Preferably, the enlarged tension releasable means is an open coil spring formed over a portion of a closed coil spring. When the closed coil spring is passed through a fixed spring mounting means, e.g., a buccal tube, and attached to a tooth to be repositioned, the retractive force is provided by compression of the open coil spring and expansion of the closed coil spring.