The effects of load location and misalignment on shear/peel testing of direct bonded orthodontic brackets--a finite element model.

A finite element model (FEM) of an orthodontic bracket bonded with glass ionomer cement was developed. The loading on the model simulated shear loading conditions associated with the testing of bonding system strength. The primary purpose of this project was to ascertain the effects of shear load placement and misalignment on the calculated stresses within the cement layer. Over the range of values considered, peak stress values depend profoundly on the location of force application. Peak stresses are less affected by shear force angulation.