Related Experiment Video
Updated: Jan 9, 2026
Author Spotlight: 3D Movement Assessment of Maxillary Posterior Teeth in Clear Aligner Treatment
Published on: February 23, 2024
Evaluation of the effectiveness of orthodontic treatment with Invisalign in different wear time protocols: Randomized
Tiago Fialho1,2, Christian Zamberlan Angheben2,3, Eduardo Terumi Blatt Ohira2,4
1Department of Orthodontics, Bauru Dental School, University of São Paulo, Alameda Octávio Pinheiro Brisolla 9-75, Bauru, São Paulo, SP 17012-901, Brazil.
Objective:
to investigate whether a 12-h daily wear protocol can provide similar treatment outcomes to the traditional 22-h protocol in patients undergoing treatment with Invisalign aligners, specifically in those with mild malocclusions.
Null Hypothesis:
There is no significant difference between the 22-h and the 12-h protocol.
Trial Design:
Single-centre randomized clinical trial with two parallel arms and a 1:1 allocation ratio.
Participants:
50 adult patients with Class I malocclusion and a maximum Little Irregularity Index (LII) of 2 mm.
Interventions:
Group 1 (9 men, 16 women; 38.56 ± 7.57 y) was treated with the 22-h protocol. Group 2 (12 men, 13 women; 37.15 ± 6.23 y) was treated with the 12-h protocol.
Primary Objective:
to compare the outcomes of 22-h versus 12-h daily wear in Class I patients with mild crowding.
Secondary Objective:
to compare the intercanine, inter-premolars, intermolar distances, overjet and overbite in T1 and T2 on both groups.
Randomization:
randomization sequence was generated with a 1:1 allocation ratio.
Blinding:
the measurements in the T1 and T2 scannings were made by a blinded operator.
Results:
The maxillary and mandibular Little irregularity index (LII) were significantly corrected with treatment at T2 in both groups. The mandibular LII showed a statistically greater correction in the 22-h group. There was no statistically significant difference between the groups considering maxillary and mandibular intercanine, interpremolar, intermolar widths, overjet, and overbite at T2.
Conclusion:
The recommended 12-h daily protocol for orthodontic aligner use can achieve adequate alignment in the maxilla in cases of very mild crowding. However, correction of mandibular irregularity is significantly less efficient with this protocol compared with the 22-h regimen.
Registration:
This clinical trial was registered under UTN U1111-1303-5576 at the Brazilian Registry of Clinical Trials (ReBEC).
