Distalization of maxillary molars with Invisalign aligners in nonextraction patients with Class II malocclusion

This retrospective study aimed to evaluate whether the treatment of Class II malocclusion with Invisalign aligners with sequential distalization of posterior teeth in adult patients would meet the criteria of American Board of Orthodontics (ABO) standards for the treatment and assess the predictive value of ClinCheck Pro software with the final results comparing the initial time, predictive planning using ClinCheck Pro software, and the final time without any require refinement.

The sample consisted of 32 adult patients with Class II malocclusion (n = 32 [7 men and 25 women]; mean age 35.47 ± 9.61 years). All of them used a set of Invisalign aligners; no refinement set was evaluated. The 7 measurements of the ABO Model Grading System, the millimeter measurements for the anteroposterior ratios of maxillary first molars and the overbite were used in the evaluations and were compared in phases initial time, predictive planning using ClinCheck Pro software, and the final time. For the intraexaminer reliability test, the intraclass correlation coefficient was calculated to analyze the reliability of the measures. The Shapiro-Wilk normality test was used to examine whether the variables were normally distributed. The Wilcoxon nonparametric test for paired samples was applied for variables that did not show normal distribution. The parametric Student t test for paired samples was used for variables that presented normal distribution. The significance level adopted for this study was 0.05.

In comparison between final ClinCheck and posttreatment results, the ABO index showed a statistically significant difference between the predictions and results for alignment and rotation, buccolingual inclination, overjet, occlusal contact, occlusal relationship, molar relationship, and overbite. The final score of the ABO scores did not meet the standards for Class II correction, contrary to what the ClinCheck Pro software predicted.

The null hypothesis that distalization of the posterior teeth occurs in adult patients using Invisalign aligners was rejected. The treatment of Class II malocclusion with Invisalign aligners did not occur as estimated by the virtual planning prepared by ClinCheck according to the standards for evaluating occlusal results established by the ABO at the end of the use of a set of aligners with sequential distalization.