Friction of conventional and self-ligating brackets using a 10 bracket model

Area of Science:

• Orthodontics
• Biomaterials Science
• Dental Mechanics

Background:

• Previous in vitro studies on bracket-archwire friction used limited bracket numbers (1 or 3).
• A need exists for more comprehensive testing models to accurately assess frictional resistance in orthodontic treatments.

Purpose of the Study:

• To compare frictional resistance among conventional stainless steel, Damon SL II self-ligating, and Time Plus self-ligating brackets.
• To evaluate the influence of stainless steel, nickel-titanium, and beta-titanium archwires on friction.
• To assess the effect of varying wire sizes (0.022-inch slot) on frictional forces.

Main Methods:

• A novel in vitro testing apparatus with 10 aligned brackets was utilized.
• Frictional resistance was measured for combinations of three bracket types and three archwire materials across five wire sizes.
• Each combination was tested 10 times with new bracket-wire samples to ensure reliability.

Main Results:

• Time Plus self-ligating brackets exhibited significantly lower friction compared to Damon SL II and conventional brackets.
• Damon SL II brackets showed lower friction with round wires but higher friction with rectangular archwires versus Time Plus.
• Beta-titanium archwires consistently generated higher frictional resistance than other materials.
• Frictional forces increased significantly with larger wire sizes for all bracket types.

Conclusions:

• A 10-bracket model provides valuable insights into bracket-archwire friction beyond simpler models.
• Bracket-archwire material and wire dimensions significantly impact frictional resistance in orthodontics.
• Clinicians and researchers can utilize these findings to optimize bracket-archwire selection for reduced friction.