Related Experiment Video
Updated: Mar 18, 2026

Force System with Vertical V-Bends: A 3D In Vitro Assessment of Elastic and Rigid Rectangular Archwires
Published on: July 24, 2018
Torsional strength of computer-aided design/computer-aided manufacturing-fabricated esthetic orthodontic brackets
Objective:
To fabricate orthodontic brackets from esthetic materials and determine their fracture resistance during archwire torsion.
Materials And Methods:
Computer-aided design/computer-aided manufacturing technology (Cerec inLab, Sirona) was used to mill brackets with a 0.018 × 0.025-inch slot. Materials used were Paradigm MZ100 and Lava Ultimate resin composite (3M ESPE), Mark II feldspathic porcelain (Vita Zahnfabrik), and In-Ceram YZ zirconia (Vita Zahnfabrik). Ten brackets of each material were subjected to torque by a 0.018 × 0.025-inch stainless steel archwire (G&H) using a specially designed apparatus. The average moments and degrees of torsion necessary to fracture the brackets were determined and compared with those of commercially available alumina brackets, Mystique MB (Dentsply GAC).
Results:
The YZ brackets were statistically significantly stronger than any other tested material in their resistance to torsion (P < .05). The mean torques at failure ranged from 3467 g.mm for Mark II to 11,902 g.mm for YZ. The mean torsion angles at failure ranged from 15.3° to 40.9°.
Conclusion:
Zirconia had the highest torsional strength among the tested esthetic brackets. Resistance of MZ100 and Lava Ultimate composite resin brackets to archwire torsion was comparable to commercially available alumina ceramic brackets.
More Related Videos
Related Concept Videos
Torsion of Noncircular Members
Design of Prismatic Beams for Bending
Stress Concentrations in Circular Shafts
Relation between Poisson's ratio, Modulus of Elasticity and Modulus of Rigidity
Symmetric Member in Bending
Machines: Problem Solving I
The toggle clamp system is a machine structure consisting of movable, pin-connected multi-force members that form a stabilized system to transmit forces. The...

