Clear Aligner Orthodontics: What is the Evidence for their Efficacy?

Orthodontic treatment with the Invisalign® appliance (and other clear aligners) may be more aesthetically appealing to most adult patients when compared with conventional fixed appliances. When the first clear aligner systems were introduced into the market some 20 years ago, they were very basic in their mode of force delivery. In the last ten years, the Invisalign® system has undergone some remarkable changes and refinements in order to deliver more predictable treatment outcomes and allow for the treatment of more complex malocclusions. However, there remains an issue in terms of differences between the predicted and achieved tooth movements. Some tooth movements are more difficult to achieve than others. This article aims to examine the evidence of effectiveness and predictability of Invisalign® appliances for the correction of different tooth movements.