Analysis of the influence of a new type of buccal tube base mesh design on the adhesive layer stress distribution and bond strength

Abstract

The three-dimensional finite element method was used to analyse the effect of changing the buccal tube baseplate shape on the stress magnitude and distribution at the interface between the buccal tube and the adhesive layer in a buccal tube-adhesive layer-tooth continuum under shear and tensile loads. A stress regression analysis was used to select the optimum mesh design and was verified by in vitro bond strength testing. This study involved buccal tubes with triangular mesh bases (100–400 µm mesh lengths, 100–200 µm mesh spacings, and 0, 45 and 90° angles) and a traditional quadrilateral mesh base. A finite element model of the buccal tube, adhesive layer and tooth were established. The stresses in the adhesive layer-buccal tube interface were recorded under mesial loads, distal loads, vertical loads and tensile loads. The average bond strength was measured by debonding the buccal tube with a universal testing machine and crosshead at a speed of 0.5 mm/min. Increasing the mesh length and mesh spacing decreased the von Mises stress and the first principal stress at the triangular mesh base-adhesive interface. Further analysis showed that the lowest stress and maximum mean bond strength were exhibited by the triangular mesh base (400 µm mesh length, 200 µm mesh spacing). Changes in the shape and size of the base grids affected the stress magnitude and distribution at the adhesive layer interface. The optimal triangular mesh base design in this study provides new ideas for clinical applications.