Chapter 4 Adhesive Materials

Introduction Adhesive—a material that can stick to a flat surface or bond two flat surfaces together Micromechanical bonding—bonding using surface irregularities smaller than can be seen with the naked eye or felt with a dental explorer Macromechanical bonding—bonding that can be seen or felt

Introduction (cont.) Adhesive Materials in Dentistry Acid Etching Dentinal Bonding Glass Ionomers Uses of Bonding in Dentistry

I. Adhesive Materials in Dentistry Use of adhesion/bonding in dentistry Development of dental adhesives Surface factors

A. Use of Adhesion/Bonding in Dentistry Retention of restorations Reduction of microleakage Reduction of recurrent caries

Microleakage and Percolation

B. Development of Dental Adhesives Historical perspective Acid etching Chemical adhesion in dentistry Polycarboxylate cements Glass ionomer cements Dentinal bonding agents

C. Surface Factors Cleanliness Biofilms

D. Testing Adhesion Adhesive failure Cohesive failure

II. Acid Etching Acid-etching process Enamel Acids Time Surface Resin systems

A. Acid-Etching Process

B. Etched Enamel

C. Acids Orthophosphoric acid at 37%

D. Time 15 to 30 seconds Longer for deciduous than permanent teeth

E. The Surface Clean and dry Sensitive to contamination after etching

F. Resin Systems Low-viscosity resin Polymethyl methacrylate–like polymer Set via addition polymerization Composite material Placed after bonding resin Chemically bonds to resin

Enamel Bonding System and Composite Material

III. Dentinal Bonding Dentinal bonding systems Three-step dentinal bonding systems Two-step dentinal bonding systems Two-step systems with self-etching primers One-step self-etching adhesives Courtesy of BISCO, Inc.

Dentinal Bonding Systems

A. Dentinal Bonding Systems Tooth tissues Structure of dentin Smear layer Historical fallacies and dentinal bonding History of dentinal bonding systems

B. Three-Step Dentinal Bonding Systems Etch dentin and enamel Apply primer Apply adhesive Composite placement Dentinal bonding adhesive mechanisms Clinical research

B. Three-Step Dentinal Bonding Systems (cont.)

B. Three-Step Dentinal Bonding Systems (cont.)

5. Dentinal Bonding Adhesive Mechanisms Micromechanical bonding Resin tags Formation of hybrid layer composed of: Resin Decalcified dentin

C. Two-Step Dentinal Bonding Systems Etch Apply adhesive

C. Two-Step Dentinal Bonding Systems— Etchant not Shown (cont.)

E. One-Step Systems with Self-Etching Primers

IV. Glass Ionomers Materials based on polyacrylic acid Polycarboxylate and glass ionomer cements Bonding mechanisms of glass ionomers

C. Bonding Mechanisms of Glass Ionomers

V. Uses of Bonding in Dentistry Adhesion Sealants Dentinal Composite restorations Glass ionomer Cervical lesions in both dentin and enamel Patient with high caries risk Courtesy of Dr. Birgitta Brown, Morgantown, WV. Courtesy of GC America, Inc.