Comparing occlusal contact quality after aligner and fixed appliance treatment using computerized occlusal analysis during 6 months of retention

Abstract

Objective Less than ideal contacts have been reported following aligner therapy, which is believed will resolve with settling, despite settling improving occlusal balance has not been scientifically confirmed. The aim of this study was to compare the outcome quality of occlusal contacts in patients treated with fixed appliances or clear aligners. Methods 39 orthodontic patients (14 treated with aligners; 25 with fixed appliances) were evaluated with a digital occlusal analysis system (T-scan10 ™), assessing Maximum Intercuspation contact simultaneity, symmetry, and relative force distribution. The Occlusion Time, the Right/Left force percentage (%R/L), the Anterior/Posterior contact ratio (RAP), and the anteroposterior Center of Force (COF) locations were recorded at treatment completion, and 3 and 6 months after. Results No significant differences in measured occlusal contact quality parameter were found between groups at treatment completion or follow-up (OT, %R, RAP nor COF position). The COF moved posteriorly and remained stable after 3 months, near to the first molar, but was located more anterior in females (p= 0.01). 10 patients finished treatment with marked asymmetry, (%R/L > 50±10%), especially in the fixed appliance group (9/25 =3 6%) versus the aligner group (1/14 = 7%). 1/3 of all patients (both groups combined) after 6 months retention had %R/L imbalances > 50±10%. Conclusions Occlusal contacts were comparable at completion of treatment with aligners or brackets and after 3-6 months of retention. Contacts increased in the posterior region with time, but settling did not improve marked asymmetry in all patients.