Comparison of load transmission and bracket deformation between titanium and stainless steel brackets

This study measures the load transmitted and structural integrity of stainl ess steel and titanium brackets on application of torsional forces. Both 0. 018 and 0.022 inch slot size edgewise brackets were tested in a specially d esigned apparatus that applied a torque value of 45 degrees. The load gener ated was measured by an Instron Universal Testing Machine at intervals of 1 5 degrees, 30 degrees, and 45 degrees of torque application. The structural stability of the brackets was evaluated by measuring the bracket slot widt h with a traveling stereoscopic microscope before and after the brackets we re subjected to torsional forces. The specimen population was composed of 8 0 brackets and 80 wire specimens. An independent sample t test was used for comparison of mean load generated at 45 degrees of torque application. Rep eated measures ANOVA (one-way) comparison was used to evaluate changes in l oad at different torque levels for the stainless steel and titanium bracket s. A paired t-test (two-tail) was used to determine the difference between initial and final bracket slot width at 45 degrees of torque applied for th e two bracket types. The titanium brackets transmitted higher loads at 15 d egrees and 30 degrees torque and lower load at 45 degrees torque on applica tion of torsional forces in comparison to stainless steel brackets. The tit anium brackets demonstrated superior dimensional stability compared to stai nless steer brackets (P < .0001).