Dental Adhesives (Bonding Agents)
Strategies
- Etch-and-rinse (total-etch) — phosphoric acid removes the smear layer; 4th gen (3-step) and 5th gen (2-step, one bottle). Best enamel bond.
- Self-etch — acidic monomers etch and prime simultaneously; 6th gen (2-step) and 7th gen (all-in-one). Less technique-sensitive, less post-op sensitivity.
Popular Systems
The 5th generation one-bottle etch-and-rinse is widely used; 7th generation is the simplest all-in-one. Universal adhesives can be used in either mode.
Smear Layer
Total-etch removes it; self-etch incorporates/dissolves it. Hybrid layer formation (resin into demineralised dentin) is key to durable dentin bonds.
Exam Tips ⭐
Total-etch (4th/5th) = best enamel bond; self-etch (6th/7th) = less sensitivity; 7th gen = all-in-one.