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Over-etching effects on micro-tensile bond strength and failure patterns for two dentin bonding systems
1Department of Operative Dentistry and Endodontics, School of Dentistry, Iwate Medical University, Morioka, Iwate 020 8505, Japan. masanori-h@mue.biglobe.ne.jp
Journal of Dentistry
|October 17, 2002
Summary
Longer acid etching times weakened resin-dentin bonds, particularly for the One-Step adhesive. The hybrid layer
Area of Science:
- Dental Materials Science
- Adhesive Dentistry
- Biomaterials Engineering
Background:
- Resin-dentin bonding is crucial for durable dental restorations.
- Understanding the weakest link in the bond is essential for improving longevity.
- The effect of phosphoric acid etching time on demineralized dentin requires further clarification.
Purpose of the Study:
- To identify the weakest zone within resin-dentin bonds.
- To correlate bond strength with failure modes.
- To elucidate the impact of demineralized dentin on bond integrity.
Main Methods:
- Human premolars were acid-etched for varying durations (15-180s).
- Resin-dentin bonds were formed using One-Step and OptiBond Solo adhesives.
- Microtensile bond strength testing and Scanning Electron Microscopy (SEM) fractography were performed.
Main Results:
- One-Step bond strength significantly decreased with increased etching time (p<0.05).
- OptiBond Solo showed significantly higher bond strength at 15s etching compared to longer times (p<0.05).
- SEM analysis revealed an increased hybrid layer area with longer etching times for both adhesives.
Conclusions:
- The integrity of the hybrid layer, particularly its superficial region, influences bond strength.
- Optimizing phosphoric acid etching time is critical for robust resin-dentin bonds.
- Adhesive system choice impacts the susceptibility of bond strength to etching duration.