Preliminary feasibility torque mechanical evaluation for 3D printed orthodontic springs with different parameters: in vitro study.
BACKGROUND
The purpose of the presented investigation is to evaluate the resulting torque on loaded 3D printed springs using different coil thickness and length.


METHODS
Specimens were designed and printed using the 3D printer MAX (Asiga, Sydney, Australia) with 3D printable, experimental, flexible material (Code:BM2008, GC, Tokyo, Japan). The specimens were divided into three groups according to spring coil design. Control group (n = 18), length group (n = 19) and thickness group (n = 22). Groups were tested using a Sauter Machine for torque calculation (DB, Grindelwald, Switzerland) in conjunction with a universal testing machine (Zwick Z010, Ulm, Germany) for clock-wise and anti-clockwise testing. Statistical analysis was performed using the Steel-Dwass test to compare median values of the three groups in both testing directions (p < 0.001).


RESULTS
The highest torque value was determined in the thickness group for both clockwise and anti-clockwise testing directions, achieving 44.00 N/mm and 39.62 N/mm respectively. The length group ranged from 21.65 to 11.04 N/mm in clockwise direction and from 18.04 to 11.38 N/mm in counter-clockwise testing. The control group ranged from 22.72 to 17.18 N/mm in the clock-wise direction while in the anti-clock wise testing it ranged from 21.34 to 16.02 N/mm.


CONCLUSIONS
The amount of torque produced from the computer aided designing/computer aided manufacturing (CAD/CAM) springs is being affected by diameter more than the length design parameter in comparison to the control group. The values of the thickness group are significantly higher than those of the length group (P < 0.001).
['Othman|Ahmed|A|0000-0003-1381-7944', 'Hartman|Steven|S|', 'Ströbele|Dragan|D|', 'Arnold|Jassin|J|', 'See|von|V|']
D001315:Australia D017076:Computer-Aided Design D005240:Feasibility Studies D005858:Germany D006801:Humans D007564:Japan D008422:Materials Testing D066330:Printing, Three-Dimensional D013557:Switzerland D019415:Torque
Torque 3D printing Springs CAD/CAM Digital orthodontics