Direct bonding of orthodontic brackets

Area of Science:

• Dental Materials Science
• Orthodontic Adhesion Technology

Background:

• Direct bonding of orthodontic brackets to enamel is a common procedure.
• Resin-based adhesives, typically bisphenol-GMA, are used for bracket attachment.
• The bond strength between the adhesive and the bracket material is a critical factor.

Purpose of the Study:

• To investigate the adhesive bonding of orthodontic brackets to enamel using various resin systems.
• To identify the limiting factor in direct-bonding procedures.
• To explore preconditioning methods to enhance bracket-adhesive bonding.

Main Methods:

• Evaluation of commercially available and synthesized bisphenol-GMA based resin systems.
• Assessment of adhesive bond strength to both enamel and bracket materials.
• Testing of bracket base roughening techniques using resin powder.

Main Results:

• Maximum average bond strength to enamel was 121 Kg/cm²; maximum adhesion to bracket material was 53 Kg/cm².
• Adhesion to the bracket material was identified as the primary limitation.
• Roughening the bracket base with resin powder yielded the best bonding results.

Conclusions:

• The bond strength to the bracket material is the bottleneck in direct orthodontic bracket bonding.
• Bracket surface preparation, such as roughening with resin powder, can significantly improve adhesion.
• Future research should prioritize not only increasing average bond strength but also reducing variability for enhanced reliability.