Glass ionomer cements as luting agents for orthodontic brackets

Area of Science:

• Dental Materials Science
• Orthodontic Adhesives
• Biomaterials

Background:

• Orthodontic bracket bonding relies on adhesive materials to ensure long-term stability.
• Resin-reinforced glass ionomer cements offer potential advantages over traditional composite resins.
• Evaluating the bond strength of novel glass ionomer cements is crucial for clinical application.

Purpose of the Study:

• To evaluate the shear bond strength of Fuji Ortho LC and GC Fuji Ortho resin-reinforced glass ionomer cements.
• To compare the bonding performance of these glass ionomer cements with conventional resin composite systems.
• To assess the influence of conditioning and environmental conditions (wet/dry) on bond strength.

Main Methods:

• 264 bovine incisors were bonded with SPEED central incisor brackets using Fuji Ortho LC, GC Fuji Ortho, Phase II, and Transbond XT.
• Experimental groups included conditioned and unconditioned enamel under wet and dry conditions.
• Shear bond strength was tested after 24 hours and 7 days incubation; Adhesive Remnant Index (ARI) and SEM were used for analysis.

Main Results:

• No significant difference in bond strength was found between Fuji Ortho LC and GC Fuji Ortho under wet or dry conditions when enamel was conditioned.
• Both glass ionomer cements showed acceptable bonding performance.
• Transbond XT consistently yielded the highest mean shear bond strength across incubation periods.
• A positive correlation was observed between Adhesive Remnant Index scores and bond strength.

Conclusions:

• Fuji Ortho LC and GC Fuji Ortho are acceptable for orthodontic bracket bonding when enamel is properly conditioned.
• Conventional resin composite Transbond XT demonstrated superior shear bond strength compared to the tested glass ionomer cements.
• Environmental conditions (wet/dry) did not significantly impact glass ionomer bond strength post-conditioning.