Invisalign® treatment in the anterior region: were the predicted tooth movements achieved?
OBJECTIVE
Based on our previous pilot study, the objective of this extended study was to compare (a) casts to their corresponding digital ClinCheck® models at baseline and (b) the tooth movement achieved at the end of aligner therapy (Invisalign®) to the predicted movement in the anterior region.


METHODS
Pre- and post-treatment casts as well as initial and final ClinChecks® models of 50 patients (15-63 years of age) were analyzed. All patients were treated with Invisalign® (Align Technology, Santa Clara, CA, USA). Evaluated parameters were: upper/lower anterior arch length and intercanine distance, overjet, overbite, dental midline shift, and the irregularity index according to Little. The comparison achieved/predicted tooth movement was tested for equivalence [adjusted 98.57% confidence interval (- 1.00; + 1.00)].


RESULTS
Before treatment the anterior crowding, according to Little, was on average 5.39 mm (minimum 1.50 mm, maximum 14.50 mm) in the upper dentition and 5.96 mm (minimum 2.00 mm, maximum 11.50 mm) in the lower dentition. After treatment the values were reduced to 1.57 mm (minimum 0 mm, maximum 4.5 mm) in the maxilla and 0.82 mm (minimum 0 mm, maximum 2.50 mm) in the mandible. We found slight deviations between pretreatment casts and initialClinCheck® ranging on average from -0.08 mm (SD ± 0.29) for the overjet and up to -0.28 mm (SD ± 0.46) for the upper anterior arch length. The difference between achieved/predicted tooth movements ranged on average from 0.01 mm (SD ± 0.48) for the lower anterior arch length, up to 0.7 mm (SD ± 0.87) for the overbite. All parameters were significantly equivalent except for the overbite (-1.02; -0.39).


CONCLUSIONS
Performed with aligners (Invisalign®), the resolvement of the partly severe anterior crowding was successfully accomplished. Resolving lower anterior crowding by protrusion of the anterior teeth (i.e., enlargement of the anterior arch length) seems well predictable. The initial ClinCheck® models provided high accuracy compared to the initial casts. The achieved tooth movement was in concordance with the predicted movement for all parameters, except for the overbite.
Department of Orthodontics, Medical Centre of Johannes Gutenberg-University Mainz, Augustusplatz 2, 55131, Mainz, Germany. Elena.krieger@unimedizin-mainz.de
Elena
E
Krieger
Jörg
J
Seiferth
Ivana
I
Marinello
Britta A
BA
Jung
Susanne
S
Wriedt
Collin
C
Jacobs
Heinrich
H
Wehrbein
D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D008310:Malocclusion / Q000534:rehabilitation*; D008875:Middle Aged; D016382:Orthodontic Appliance Design / Q000379:methods*; D009968:Orthodontic Appliances, Removable; D009971:Orthodontics, Corrective / Q000295:instrumentation* / Q000379:methods; D011379:Prognosis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013813:Therapy, Computer-Assisted / Q000379:methods*; D014087:Tooth Movement Techniques / Q000295:instrumentation*; D016896:Treatment Outcome; D055815:Young Adult