TIME-DEPENDENT FIT ADAPTATION OF TWO ALIGNER MATERIALS: A SCANNING ELECTRON MICROSCOPY STUDY

Background: The goal of the study is to analyze and differentiatethe changes in adaptation of aligner at attachment along with time of two different aligner materials after intra oral usage:Polyethylene terephthal ate-Glycol andCo-polyester.

Materials and methods:A total of 20 aligner appliances(N=20)were studied, comprising OF 10 Polyethylene Terephthalate Glycol (PET-G) aligners and 10 Co-polyester aligners . These aligners were evaluated at two time points: just before use (T0) and after 15 days (T15) of intraoral usage.Each aligner was used for a 15-day period and then adapted to its corresponding 3D-printed resin model. The aligners were sectioned bucco-lingually at the ellipsoid attachment area, and five samples per material per time point(n=5)were analyzed.Scanning Electron Microsco py (SEM) was employed to measure gap width changes at five distinct levels within the attachment region. The mean values of gap width changes were statistically analyzed to compare the fit between PET-G and Co-polyester aligners.

Results: Statistically significant differences (P0.005) in fit of aligner were observed at given time points: co-polyester exhibited the smallest gap at T0, while PET-G showed the largest. Likewise, at various attachment levels, significant differences were found at T15 with the smallest gaps occurring at all the levels except at incisal and gingival end of ellipsoid attachment.