Using digital image correlation to measure displacement and strain during involving distal movement of anterior teeth with clear aligner.

To investigate methods to suppress the bowing effects of lingual inclination and anterior tooth extrusion, digital image correlation (DIC) was used to evaluate aligner displacement in three-dimensions through comparing the distal movement of six and four anterior teeth. Computed tomography scans were used to measure aligner thickness and shape. Based on displacement direction and magnitude, a desirable deformation mode with minimal lingual inclination and extrusion was observed during distal movement of four anterior teeth.

Measurement of elastic strain recovery in an orthodontic aligner as a driving force for orthodontic treatment.

Orthodontic aligners undergo deformation during installation, producing an unexpected component of elastic restoring force that causes unintended changes in the dentition. The aim of this study was to investigate the relationship between strain and elastic recovery of the aligner. We distinguished the contributions to aligner deformation due to molding and installation by measuring the thickness distribution of an aligner after molding using micro-CT and tracking changes in grid patterns drawn on the sheet used to fabricate the aligner.