Aligners are orthodontic devices that are used to move and straighten the teeth. They are thin, plastic foils that are stretched over the whole teeth quadrant and can be fitted and removed by the patients themselves. Aligners are practically invisible, do not normally inhibit speech and can be removed whilst eating or cleaning the teeth. For these reasons, aligners can be worn by adults at work during the day. Aligners are manufactured in such a way that they exert gentle pressure on the teeth enabling their position to be altered. Since only very small movements can be achieved with an aligner, a complete series of aligners is normally produced, each one being worn for about 2-3 weeks at a time. Each new aligner moves the tooth a little bit more so that the teeth are gradually straightened step by step.
Aligners were originally produced by hand in the orthodontic laboratory by cutting out the teeth from the patient’s jaw model and putting them back in a straightened position (Setup). Thermo-plastic foils are then produced from these Setup models and made into aligners. They have been further developed over the years by using CAD/CAM software which enables virtual Setups to be produced on the computer screen. At the same time, Setup-models can be manufactured using this software. The latest aligner systems such as Invisalign and eCligner are largely computer-based.