Torque expression of self-ligating brackets compared with conventional metallic, ceramic, and plastic brackets

Area of Science:

• Orthodontics
• Biomaterials Science
• Dental Mechanics

Background:

• Orthodontic brackets are crucial for tooth alignment.
• Self-ligating brackets offer potential advantages over traditional edgewise brackets.
• Understanding torque capacity is vital for effective orthodontic treatment.

Purpose of the Study:

• To compare the torque capacity of active and passive self-ligating brackets against metallic, ceramic, and polycarbonate edgewise brackets.
• To evaluate torque loss in different bracket types under simulated clinical conditions.

Main Methods:

• Six bracket types (Speed, Damon2, SS, Ultratrimm, Discovery, Fascination 2, Brillant) with 0.022-inch slots were tested.
• 0.019 x 0.025-inch stainless steel archwires were used to apply 20 degrees of torque.
• The Orthodontic Measurement and Simulation System (OMSS) measured labial crown torque and torque loss.

Main Results:

• The ceramic bracket (Fascination 2) exhibited the highest torquing moment (35 Nmm).
• Ceramic and one stainless steel bracket showed the lowest torque loss (4.6 degrees).
• Self-ligating, polycarbonate, and some metallic brackets demonstrated significantly reduced moment and increased torque loss.

Conclusions:

• Ceramic brackets offer superior torque control compared to other types.
• Bracket material and design significantly influence torque transmission and efficiency in orthodontics.
• Findings provide insights for selecting optimal brackets for predictable tooth movement.