In Vitro Comparison of Direct Attachment Shape and Size on the Orthodontic Forces and Moments Generated by Thermoplastic Aligners During Expansion.

ABSTRACT:

Objective

To evaluate the effects of varying direct attachment shape and size on the forces and moments generated by thermoplastic aligners during simulated expansion.

Materials and methods

An in vitro orthodontic force tester (OFT) was used to measure the forces and moments from a typodont where the buccal teeth were translated lingually 0.2 mm to simulate expansion. Hemi-ellipsoid and rectangular attachments with either 0.5 or 1.0 mm thickness were added on upper right first premolar (UR4), second premolar (UR5) and first molar (UR6). Analysis of variance (ANOVA) was used to determine two-way interactions among the factors on the outcomes.

Results

The interactions between group and tooth were significant for all outcomes (p < 0.001). The greatest buccal forces (Fy)

SUBMITTER: Lear M 

PROVIDER: S-EPMC11897421 | biostudies-literature | 2025 Apr

REPOSITORIES: biostudies-literature