Treatment and Post-treatment Posterior Occlusal Changes in Invisalign® and Traditional Braces: A Randomized Controlled

Abstract

Invisalign® and traditional braces are two treatment modalities available for patients seeking orthodontic improvement. The purpose of the present study was to compare treatment and post-treatment posterior occlusal changes in adult subjects with Class I malocclusion treated with Invisalign® or traditional braces. The study’s retention protocol was upper wraparound Hawley with bonded lower 3-3 retainer. Blu Mousse® bite registrations and orthodontic study models were collected at pre-treatment (T1), debond (T2), 1 month into retention (T3), and 6 months into retention (T4). Areas of contact and near contact (ACNC) were evaluated at 0-350 microns, as well as marginal ridge and buccolingual inclination scores from the American Board of Orthodontics’ Cast-Radiograph Evaluation (ABO CRE). Orthodontic treatment decreased ACNC in both treatment groups significantly (p< 0.05); ACNC decreased between 54-75% during treatment. The most significant ACNC increase occurred between T2-T3 in both groups, between 25-94%. Though settling continued, there was no significant change in either group between T3-T4. Neither group achieved pre-treatment ACNC values by six months of retention. Likewise, no significant changes in mean marginal ridges nor buccolingual inclination scores occurred in either group over the course of the study. According to longitudinal analyses, there were no significant between-group differences at any timepoint, indicating that Invisalign® and traditional braces can have similar treatment results as well as settle similarly during six months of retention. It could be of benefit to the patient to consider equilibration during the retention phase to alleviate interferences that inhibit further settling and improvement in ACNC.