Resin-modified glass ionomers: dentin bond strength versus time

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Adhesive Dentistry

Background:

• Dentin bond strength testing typically uses 24-hour water storage.
• Clinical debonding can occur shortly after restoration placement under stress.
• Understanding early bond development is critical for clinical performance.

Purpose of the Study:

• To investigate the rate of shear bond strength development in resin-modified glass-ionomer cements.
• To compare the early bond strength development of Fuji II LC and Vitremer with conventional glass-ionomer (Fuji II) and a resin composite (Herculite XRV/OptiBond).

Main Methods:

• Bovine incisors were prepared to expose dentin.
• Shear bond strengths were measured at multiple time points (1 min to 24 hrs) after water storage at 37°C.
• Statistical analysis (ANOVA, Dunnet test) identified the 'initial increasing time' for bond strength.

Main Results:

• All tested materials showed increased dentin bond strength over time.
• Initial significant bond strength increases occurred at 10 minutes for Fuji II LC and OptiBond, 20 minutes for Fuji II, and 60 minutes for Vitremer.
• Varying initial increasing times were observed among the different dental materials.

Conclusions:

• The rate of dentin bond strength development varies significantly among different dental cements and restorative systems.
• Early development of bond strength is material-dependent and has potential clinical implications for restorations subjected to immediate stress.