Table 2.
Characteristics of included clinical trials.
| Study | Type of Study | Setting | Analyzed Sample | Auxiliary Elements | Analysis Methods | Performed Movements | Duration of Treatment | Outcome |
|---|---|---|---|---|---|---|---|---|
| Dai et al. [23] | Case Series | The Second Dental Center, Peking University School and Hospital of Stomatology |
30 patients (4 M–26 F) Age: 19.4 ± 6.3 First premolar extraction cases treated with Invisalign. Three variables considered: -Age -Type of attachment -Initial crowding |
On first molar: -Vertical attachment (3mm) -Horizontal attachment (3mm) -Horizontal attachment (5mm) -G6 optimized attachment |
Superimposition of: -Real and virtual pre-treatment models -Real pre- and post-treatment models -Virtual pre- and post-treatment models -All four models |
On first molar: -M-D TIPPING -M-D TRANSLATION -O-G TRANSLATION On central incisor: -TORQUE -V-L TRANSLATION -O-G TRANSLATION |
22.3 ± 4.6 months Aligner change every 1–2 weeks |
- Difference between predicted and achieved tooth movement in maxillary first molar and central incisor -Influence of age, initial crowding and type of attachment |
| Durrett [20] | RCT | University of Florida Orthodontic Research clinic | 99 patients reduced to 86 Age: 18+ 6 configurations: -5 groups with different attachments -1 control group (without attachments) 2 groups: -Extraction and non-extraction cases |
-No attachments (Group C) -Attachments with different shapes on the buccal surface (Groups A-B-D-F) -Attachments bonded to both buccal and lingual surfaces (Group E) |
Superimposition of: initial models and final models or first reboot |
-ROTATION of canine and premolar -INTRUSION and EXTRUSION of incisor, canine and premolar |
Minimum 2 years Aligner change every 2 weeks |
-ROTATION: Comparison between predicted and achieved tooth movement in reboot and non-reboot cases -INTRUSION and EXTRUSION: Comparison between predicted and achieved tooth movement in reboot cases |
| Garino et al. [16] | RCT | Orthodontic clinics in Turin and Vancouver Collections of the AAO Foundation Craniofacial Growth Legacy |
30 patients with class II malocclusion (12 M–18 F) Age: 30.5 3 configurations: -Group C1—5 attachments per quadrant -Group C2—3 attachments per quadrant -Group C—Control |
Vertical rectangular attachments -Group C1—From maxillary canine to second molar -Group C2—From maxillary first premolar to first molar Class II elastics in the first phase Power ridge in the second phase |
Superimposition of T0 and T1 cephalograms | -Maxillary molars DISTALIZATION -Incisors RETRACTION |
Average time:24.3 months Aligner change every 2 weeks |
Comparison of the position of upper molars and central incisors between T0 and T1 (angular, horizontal and vertical measurements expressed as angles and distances from y-axis, x-axis and occlusal plane). |
| Kravitz et al. [22] | Prospective CCT | Department of Orthodontics—University of Illinois-Chicago | 38 pazients reduced to 31 (13 M–18 F) Average age: 29.4 3 configurations: -Attachment only group (AO) -Interproximal-reduction only group (IO) -Group without attachments (N) |
Attachemnt Only group: -Vertical or horizontal ellipsoid attachments -Horizontal rectangular attachments |
Superimposition of the final stage of the pre-treatment model (ClinCheck) and the post-treatment model | Maxillary and mandibular canine ROTATION | Average time:7.2 months Aligner change every 2–3 weeks |
Comparison between the amount of rotation predicted and the amount of rotation actually achieved |
| Simon et al. [21] | Retrospective CCT |
Private practice-Cologne (Germany) |
30 patients (11 M–19 F) reduced to 26. Age: 32.9 3 configurations: -Incisors with attachments or power-ridges -Premolars with or without attachments -Molars with or without attachments |
Incisor TORQUE: -Horizontal ellipsoid attachment or power ridge Premolar DEROTATION: -Optimized Attachment or no attachment Molar DISTALIZATION: -Horizontal Attachment Bevelled in gingival direction or no attachment |
-Superimposition between the initial situation (T1) and the final stage of ClinCheck (Clin T2) -Superimposition between the initial situation (T1) and the actual post-treatment condition (T2) |
-Incisor TORQUE > 10° -Premolar DEROTATION > 10° -Molar DISTALIZATION > 1.5 mm |
Number of aligners: 18 aligners on average |
-Comparison between (T2-T1) and (ClinT2-T1) to evaluate treatment efficacy with or without attachments and power ridges - Analysis of the accuracy of premolar derotation according to the staging (degree of derotation per aligner) and to the total amount of predicted movement |