Dentin Adhesion: Mechanism, Applications, and Key Factors

What is dentin bonding?

Dentin bonding is the process by which a restorative material chemically or mechanically adheres to the dentin of the tooth. Unlike enamel, dentin is a less mineralized tissue with a more porous structure, which makes its adhesion more complex and dependent on interaction with specific adhesive agents.

This procedure is key in restorative treatments, cementation of veneers and prostheses, as well as root canal sealing in endodontics.

Mechanism of dentin bonding

The success of dentin bonding is based on the formation of the hybrid layer, a structure resulting from the interaction between demineralized dentin and adhesive monomers.

🔹 Acid etching: Orthophosphoric acid (37%) is used to remove the smear layer and expose the collagen network.
🔹 Adhesive infiltration: Resin monomers penetrate the collagen mesh and, after photopolymerization, form a cross-linked structure.
🔹 Polymerization: The curing light activates the adhesive, creating mechanical and chemical bonds with the underlying dentin.

Types of dentin adhesive systems

There are different adhesive systems in restorative dentistry, each with advantages and disadvantages:

• Etch-and-rinse systems (total-etch): Require the application of phosphoric acid prior to adhesive placement.
• Self-etch systems: Contain weak acids that etch and penetrate the dentin without the need for rinsing.
• Universal systems: Combine both approaches and can adapt to various clinical techniques.

Factors influencing dentin bonding

To achieve strong and durable adhesion, several clinical factors must be controlled:

✔️ Dentin moisture: Excessive drying collapses the collagen network, reducing the adhesive's penetration capacity.
✔️ Type of adhesive used: Some systems offer greater resistance to degradation over time.
✔️ Contamination with saliva or blood: Reduces adhesion by interfering with adhesive polymerization.
✔️ Polymerization mode: The quality of the curing light influences the stability of the adhesive bond.

Clinical applications of dentin bonding

Dentin adhesion is essential in multiple dental procedures, including:

🦷 Direct composite resin restorations
🦷 Cementation of ceramic veneers and crowns
🦷 Root canal sealing in endodontics
🦷 Restorations of teeth worn by bruxism or abrasion

Complications and failures in dentin bonding

If adhesion is not performed correctly, clinical problems may arise such as:

⚠️ Marginal leakage: Entry of bacteria between the restoration and the tooth, causing secondary caries.
⚠️ Restoration detachment: Occurs when adhesion is insufficient or degrades over time.
⚠️ Postoperative sensitivity: May occur if the hybrid layer is not formed correctly.

Conclusion

Dentin bonding is a complex but essential process for the success of restorative treatments. Correct adhesive selection, moisture control, and proper acid etching application are key to ensuring strong and durable adhesion.

Legal Notice and Disclaimer

This article is part of the ONAK Dictionary of Medical Terms and is for informational purposes. It does not replace consultation with a dentist.

ONAK is not responsible for the misuse of the information contained in this article. It is recommended to consult a specialist for an accurate diagnosis and appropriate treatment.

Bibliography

1. Van Meerbeek, B., Yoshida, Y., Van Landuyt, K. "Adhesion to enamel and dentin: current status and future challenges." Oper Dent. 2003; 28(3): 215-235. Available at: https://pubmed.ncbi.nlm.nih.gov/12760694/

2. Pashley, D. H., Tay, F. R. "Dentin adhesion: current concepts and future challenges." J Prosthet Dent. 2001; 83(3): 259-267. Available at: https://pubmed.ncbi.nlm.nih.gov/11274696/

3. Perdigão, J., Geraldeli, S. "Bonding strategies to dentin: comparing the durability of universal adhesives." Dent Mater. 2015; 31(9): 1003-1012. Available at: https://pubmed.ncbi.nlm.nih.gov/26142016/