Accuracy of dental arch form in customized fixed labial orthodontic appliances

Predictability of orthodontic tooth movement with aligners: effect of treatment design

“…Differences among the studies could be related to the fact that patients considered by Goh et al were treated with a maximum number of 14 aligners, therefore with simplest malocclusions with respect to the ones analyzed by our team, and to different applied methodologies for data collection. Furthermore, as described by Al-Nadawi et al and Deregibus et al [ 34 , 35 ] these results may be due to the flexibility of the material and to the occlusal forces, so as well as it happens in fixed orthodontics, overcorrection should be added to the end of the customized archwire to reduce posterior arch discrepancies [ 36 ]. According to Cattaneo et al, occlusal forces can affect OTM, and therefore, if aligners do not release enough force to overcome the resistance of the system, teeth could not achieve the planned position, precluding torque and tip control [ 13 , 37 ].…”

“…The mechanical behavior of the distal portion of the aligners is similar to what happen with traditional fixed appliances and in relation to the decreasing amount of force exerted by the end of an arch wire as interbracket distance and flexibility of the wire increase. Therefore, lower forces could be released resulting in less accurate movement [ 36 , 48 ]. This aspect could well describe the differences observed in this study between the planned and the achieved positions of the upper and lower second molars.…”