# Evaluation of Tooth Movement Accuracy with the F22 Aligner System: A Retrospective Study
## 5 Conclusions  
From the results of the following study, it is possible to conclude that:  
* In mild-to-moderate cases of Class I malocclusion, the F22 Aligner system displays excellent accuracy for inclination (86.76% \(\pm\) 44.89%) and angulation movements (88.01% \(\pm\) 55.68%), but only moderate for rotation (61.59% \(\pm\) 32.54%).
* It is least accurate at the derotation of rounded teeth, in particular maxillary (49.59% \(\pm\) 29.43%) and mandibular amines (57.70% \(\pm\) 28.90%) and mandibular premolars (54.19% \(\pm\) 35.79%). The derotation of maxillary premolars is more accurate (62.86% \(\pm\) 35.03%), presumably due to their squarer crowns, and they were positively affected by the application of grip points.
* The percentage of prescribed angulation achieved depends on the amount of prescribed movement, the direction of movement (difference between distal and mesial tipping) and the tooth type (greater for maxillary premolars and canines, and mandibular incisors). Moreover, the presence or absence of grip points in mesial crown tipping presents a paradoxical effect.
* The percentage of rotation achieved depends on the tooth type, and is lowest for the rounded teeth, which is not improved by the application of grip points, with the exception of the maxillary premolars. For the remaining tooth types investigated, the accuracy is greater, and improves with the use of grip points.
* For all the movements investigated, the variables sex and age influence the percentage of movement achieved, which is greater in the intermediate age group (young adult patients). As for rotation, in the older group the trend seen in females (inverse relationship between accuracy and age) was reversed in males (direct relationship between accuracy and age).
* The F22 Aligner system seems to have a good expansive capacity, with differences between prescription and result always less than 1 mm. The only region where there is a significant difference between prescribed and achieved expansion was the distance between the mandibular first premolars, although the discrepancy was clinically minimal (0.24 mm).  
Conceptualization, L.L., P.M. and S.S.d.V.; methodology, L.L., P.M. and S.S.d.V.; software, P.M. and F.C.; validation, L.L., P.M. and S.S.d.V.; formal analysis, P.M., R.S. and P.F.; investigation, S.S.d.V.; resources, S.S.d.V.; data curation, P.M., S.S.d.V. and P.F.; writing--original draft preparation, S.S.d.V., P.M. and P.F.; writing--review and editing, P.M. and P.F.; visualization, L.L., P.M. and S.S.d.V.; supervision, L.L. and P.M.; project administration, L.L. and P.M. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
The study was conducted in accordance with the Declaration of Helsinki, and approved by the Institutional Review Board (or Ethics Committee) of the University of Ferrara (protocol code 9/2020, 7 January 2020).  
Informed Consent Statement: Informed consent was obtained from all subjects involved in the study.  
All authors assured that all data and materials as well as software application or custom code support their published claims and comply with field standards. The raw data supporting the conclusions of this article will be made available by the corresponding author on request.  
**Acknowledgments: Authors give special thanks to [PERSON], [PERSON], [PERSON], [PERSON], [PERSON] and [PERSON], who contributed to the development of the F22 Aligner system.**