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Published on: July 10, 2014
Sequential nano-amorphous calcium phosphate application modulates resin-dentin bonding performance and aging
1Department of Cariology and Operative Dentistry, Graduate School of Medical and Dental Sciences, Institute of Science Tokyo (ISCT), 1-5-45, Yushima, Bunkyo-Ku, Tokyo 113-8549, Japan.
Summary
Applying nano-amorphous calcium phosphate (NACP) solution after the primer improves long-term resin-dentin bonding. This sequence-dependent approach enhances adhesion, especially for demineralized dentin, acting as a bio-functional booster.
Area of Science:
- Biomaterials Science
- Dental Adhesion
- Nanotechnology in Dentistry
Background:
- Two-step self-etch bonding procedures are common in restorative dentistry.
- Improving resin-dentin bond durability, especially on demineralized surfaces, remains a challenge.
- Nano-amorphous calcium phosphate (NACP) has potential as a bioactive additive.
Purpose of the Study:
- To evaluate the impact of sequentially applying NACP solution in a two-step self-etch bonding system.
- To compare the effect of NACP application timing (pre- vs. post-primer) on resin-dentin bonding.
- To assess the performance of both fluoride-free and fluoride-containing adhesives with NACP.
Main Methods:
- Bovine dentin samples (sound and demineralized) were used.
- A fluoride-free (SE) and a fluoride-containing (PB) adhesive were tested with NACP applied pre- or post-primer, alongside controls.
- Micro-tensile bond strength (µTBS) was measured after 24h and 10,000 thermocycles; degree of conversion (DC) and failure modes were also analyzed.
Main Results:
- NACP application sequence and time significantly affected µTBS (p<0.001).
- Post-primer NACP application (pN-PB, pN-SE) generally yielded higher initial bond strengths and more stable long-term results compared to pre-primer application (Np).
- While initial bond strengths varied, pN-SE showed significantly higher values after aging, and DC was largely unaffected by NACP.
Conclusions:
- NACP influences resin-dentin bonding in a manner dependent on application sequence and adhesive system.
- Applying NACP post-primer demonstrated more stable long-term bonding outcomes.
- This suggests NACP can serve as a 'bio-functional booster' to enhance adhesion on demineralized dentin.
