In their retrospective study, Simon et al., 12 analyzing premolar rotations of >10°, concluded that the use of attachments and the amount of movement per aligner had a great impact on the treatment predictability reducing the staging and using attachments increase the predictability of tooth movement. 10 supported the use of attachments to improve the accuracy of this movement. 13 stated that IPR influenced in a positive way the correction of rotations, while in 2005 Djeu et al. Thus, teeth with rounded crowns seem to be more difficult to rotate with CAT. Similar data were reported by Nguyen and Chen 23: incisors achieved 60% of the predicted rotation, while canines and premolars had the lowest accuracy (39%). Prospective studies 4, 13 revealed a generally low degree of control and predictability for rotations. It is thus impossible to apply a pure rotational force without a tipping movement of the tooth in its socket. This is due to the fact that the force could be distributed over the entire periodontal ligament rather than over a narrow vertical strip. 22 reported that forces required to produce rotation of a tooth around its long axis are similar to those required to produce tipping. Thus, clinicians who plan to use CAT on their patients have to rely on their clinical experience, the opinions of experts, and limited published evidence. The authors stated that no strong conclusions could be made regarding the treatment effects of this kind of orthodontic treatment. In 2005 Lagravère and Flores-Mir 6 published a review in which only two studies met their inclusion criteria related to Invisalign therapy efficacy. Although CAT has been cited as a safe, esthetic, and comfortable orthodontic procedure for adult patients, only a few investigations 4, 5 have focused on the predictability of orthodontic tooth movement (OTM). In 1997, Align Technology© (Santa Clara, Calif) adapted and incorporated modern technologies to introduce the clear aligner treatment (CAT) as we know it, rendering Kesling's concept a feasible orthodontic treatment option.
#Intrusion 2 ost series#
2 The possibility of using clear overlay orthodontic appliances was introduced in 1946, when Kesling 3 devised the concept of using a series of thermoplastic tooth positioners to progressively move misaligned teeth to improved positions. In recent years, increasing numbers of adult patients have sought orthodontic treatment 1 and expressed a desire for esthetic and comfortable alternatives to conventional fixed appliances.
0 kommentar(er)
