Current perspectives on dental adhesion: (1) Dentin adhesion - not there yet

Area of Science:

• Dental Materials Science
• Adhesive Dentistry
• Biomaterials Engineering

Background:

• The primary goal of adhesive restorations is to achieve durable bonding between restorative materials and tooth structure.
• Bonding to enamel is relatively straightforward via micromechanical interlocking, but achieving durable adhesion to dentin remains a significant challenge.
• Simplification of dental adhesive systems often involves a trade-off with clinical efficacy and long-term outcomes.

Purpose of the Study:

• To review the fundamental principles and challenges in dental adhesion.
• To analyze current adhesive strategies, their limitations, and the critical role of the dental substrate.
• To discuss the potential of chemical/ionic adhesion and the translation of laboratory research to clinical practice.

Main Methods:

• Literature review of dental adhesion research, focusing on historical contributions and current strategies.
• Analysis of bonding mechanisms to enamel and dentin, highlighting substrate-specific challenges.
• Evaluation of the clinical relevance of laboratory findings and emerging research trends.

Main Results:

• Enamel bonding is reliably achieved through micromechanical interlocking.
• Durable and effective bonding to organic, humid dentin presents a persistent challenge in adhesive dentistry.
• Many new dental adhesives lack sufficient evidence to support claims of novelty or improved properties.

Conclusions:

• The dental substrate (enamel vs. dentin) is a critical factor influencing the durability of adhesive restorations.
• Current adhesive strategies have inherent shortcomings that necessitate further research.
• Future dental adhesive materials may benefit from exploring chemical/ionic bonding mechanisms and ensuring clinical relevance of research.