Microleakage under metallic and ceramic brackets bonded with orthodontic self-etching primer systems

Area of Science:

• Dental Materials Science
• Orthodontic Adhesion
• Biomaterials

Background:

• Orthodontic bracket debonding remains a clinical concern.
• Minimizing microleakage at the enamel-adhesive interface is crucial for successful orthodontic treatment.
• Self-etching primer systems offer a simplified bonding protocol compared to conventional acid etching.

Purpose of the Study:

• To compare the in vitro microleakage of orthodontic brackets bonded with a self-etching primer system versus conventional acid etching.
• To evaluate microleakage at both enamel-adhesive and bracket-adhesive interfaces.
• To assess differences between metal and ceramic brackets and between occlusal and gingival margins.

Main Methods:

• Sixty human premolar teeth were divided into four groups: acid-etched/metal bracket, self-etching primer/metal bracket, acid-etched/ceramic bracket, and self-etching primer/ceramic bracket.
• Teeth were bonded, sealed, stained with basic fuchsine, sectioned, and examined under a stereomicroscope for microleakage.
• Kruskal-Wallis and Mann-Whitney U tests were used for statistical analysis.

Main Results:

• Gingival margins showed significantly higher microleakage than occlusal margins across all groups.
• The enamel-adhesive interface exhibited greater microleakage than the bracket-adhesive interface.
• Self-etching primer systems resulted in significantly higher microleakage at the enamel-adhesive interface on the gingival side.

Conclusions:

• Self-etching primer systems may lead to increased microleakage at the enamel-adhesive interface.
• Higher microleakage could potentially compromise bond strength and increase the risk of white-spot lesions.
• Conventional acid etching may provide a more reliable seal at the enamel-adhesive interface, especially on the gingival side.