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Dentin Bond Strength of Resin Cements Under Simulated Intraoral Humidity Conditions
Takashi Washino1, Toru Nikaido2, Michael F Burrow3
1Division of Oral Functional Science and Rehabilitation, Department of Operative Dentistry, School of Dentistry, Asahi University, Mizuho, Japan.
Summary
High intraoral humidity significantly impacts dentin bond strength of resin cements. Methyl methacrylate-based cements offer stable performance, while primer-assisted and self-adhesive types show reduced bond strength in moist conditions.
Area of Science:
- Dental Materials Science
- Adhesive Dentistry
- Biomaterials Research
Background:
- Dental trauma often necessitates emergency adhesive procedures with compromised moisture control.
- Intraoral humidity is a critical factor influencing the success of dental bonding.
Purpose of the Study:
- To evaluate the effect of varying relative humidity on the dentin bond strength of three resin cements.
- To compare the performance of methyl methacrylate-based, primer-assisted, and self-adhesive resin cements under simulated intraoral conditions.
Main Methods:
- Three resin cements were tested at 50%, 65%, 80%, and 95% relative humidity at 32°C.
- Shear bond strength was measured on bovine dentin following ISO/TS 16506:2017 Annex A.
- Failure modes were analyzed to assess bond integrity.
Main Results:
- Methyl methacrylate-based cement exhibited stable bond strength across all humidity levels.
- Primer-assisted cement showed significantly reduced bond strength at humidity levels of 65% and above, with predominantly interfacial failures.
- Self-adhesive cement displayed consistently low bond strength regardless of humidity, with frequent interfacial failures.
Conclusions:
- Resin cement type is a primary determinant of dentin bonding performance under varying intraoral humidity.
- Methyl methacrylate-based cements provide reliable bonding in humid environments.
- Primer-assisted cements are sensitive to high humidity, while self-adhesive cements offer consistently poor bond strength.
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