Restoration interface microleakage using one total-etch and three self-etch adhesives

Area of Science:

• Dental Materials Science
• Restorative Dentistry
• Adhesive Dentistry

Background:

• Microleakage is a significant concern in restorative dentistry, potentially leading to secondary caries and pulpal inflammation.
• Dental adhesives are crucial for achieving a seal between the tooth structure and restorative material, preventing microleakage.
• Evaluating the microleakage of different adhesive systems under simulated intraoral conditions is essential for clinical success.

Purpose of the Study:

• To evaluate and compare the efficacy of a total-etch adhesive and three self-etch adhesives in reducing microleakage.
• To assess the performance of these adhesives after prolonged water storage and thermocycling, simulating clinical aging.
• To determine if there are significant differences in microleakage between occlusal and gingival margins for each adhesive system.

Main Methods:

• Thirty human premolars and molars underwent Class V preparations and were restored with resin composite using four different adhesive systems: Xeno III (one-step self-etch), Prime & Bond NT (total-etch), i-Bond (one-step self-etch), and Clearfil SE Bond (two-step self-etch).
• Restored teeth were stored in distilled water for 90 days and subjected to 500 cycles of thermocycling between 5°C and 55°C.
• Microleakage was assessed using 0.5% methylene blue dye penetration, with samples sectioned and evaluated under a stereomicroscope at 20x magnification.

Main Results:

• The i-Bond one-step self-etch adhesive demonstrated significantly greater dye penetration at both occlusal and gingival margins compared to the other groups (p < 0.0001).
• No significant difference in microleakage was observed between occlusal and gingival margins for Xeno III, Prime & Bond NT, and i-Bond adhesives.
• Clearfil SE Bond showed significantly more dye penetration at the occlusal margin than at the gingival margin (p = 0.001).

Conclusions:

• The i-Bond one-step self-etch adhesive exhibited the poorest sealing ability among the evaluated systems, suggesting a higher risk of microleakage in clinical applications.
• Clearfil SE Bond, a two-step self-etch adhesive, demonstrated acceptable performance but with a tendency for more leakage at the occlusal margin.
• Further research may be warranted to optimize self-etch adhesive formulations and application techniques to minimize microleakage and enhance the longevity of dental restorations.