Orthodontic bonding using glass ionomer cement: an in vitro study

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Adhesive Dentistry

Background:

• Glass ionomer cements (GIC) are widely used dental restorative materials.
• Assessing the bond strength of GIC to tooth structure is crucial for clinical longevity.
• Understanding factors affecting GIC bond strength, such as mixing ratio and moisture, is essential for optimizing performance.

Purpose of the Study:

• To evaluate the in vitro tensile/peel bond strength of various GICs to human enamel.
• To determine the effect of moisture contamination and altered powder/liquid ratios on GIC bond strength.
• To compare the bond strength of GICs to a composite resin control.

Main Methods:

• Five GICs and one composite resin were tested.
• Bond strength was measured using an Instron testing machine after 24-hour setting.
• Enamel-cement interface analysis was performed using the Adhesive Remnant Index (ARI).

Main Results:

• All tested GICs exhibited significantly lower bond strengths compared to the composite resin.
• Increasing the powder/liquid ratio generally enhanced GIC bond strength, significantly for Intact and Orthocem B.
• Moisture contamination did not significantly impact bond strength, except for Fuji II, which showed a significant decrease.

Conclusions:

• GICs demonstrate inferior in vitro bond strength to enamel compared to composite resins.
• Optimizing the powder/liquid ratio can improve GIC bond strength.
• Clinical handling protocols should consider the potential impact of moisture on specific GIC formulations like Fuji II.