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Author Spotlight: 3D Movement Assessment of Maxillary Posterior Teeth in Clear Aligner Treatment
Published on: February 23, 2024
Risk factors for midcourse correction during treatment of first series of aligners with Invisalign
Lu Zhang1, Shuang Lin2, Jiping Chen2
1Stomatology Hospital, School of Stomatology, Zhejiang University School of Medicine, Zhejiang Provincial Clinical Research Center for Oral Diseases, Key Laboratory of Oral Biomedical Research of Zhejiang Province, Cancer Center of Zhejiang University, Hangzhou, China.
Introduction:
This study aimed to analyze risk factors for midcourse correction (MC) during the first series of aligners in treatments with Invisalign (Align Technology, Santa Clara, Calif).
Methods:
Three hundred and fourteen patients treated with Invisalign were divided into MC and non-midcourse correction groups according to whether they completed the first series of aligners. Differences between these groups were compared with independent sample t tests, chi-square tests, and Wilcoxon rank sum tests. A multivariate logistic regression analysis was performed to identify independent risk factors, including gender, age, extraction treatment, interproximal reduction, correction steps (steps in first series treatment), overbite, overjet, the curve of Spee, Angle classification, and crowding.
Results:
The percentage of females (86.3%), Angle Class I malocclusion (62.4%), and nonextraction (56.1%) was relatively higher in all 314 patients. More than half of the patients (73.6%) completed the first series of aligners. Differences between the groups in the number of patients with extraction, correction steps, and the curve of Spee were significant (P <0.05). The proportions of MC were 41.3% and 14.8% in extraction and nonextraction patients, respectively. More initially planned correction steps were seen in the MC group (53.4 ± 15.6 steps). Extraction (adjusted odds ratio, 0.375; P = 0.001) and correction steps (adjusted odds ratio, 1.06; P <0.001) were independent risk factors for MC.
Conclusions:
Extraction and the number of initially planned correction steps are independent risk factors for MC. In patients with complex dentofacial abnormalities, such as extraction, MC may be needed to achieve predicted changes.
