Does bonding to dentin reduce microleakage of composite restorations?

Area of Science:

• Dental Materials Science
• Restorative Dentistry
• Adhesive Dentistry

Background:

• Marginal microleakage is a critical factor affecting the longevity of composite resin restorations.
• The application mode of dental adhesives (enamel-only vs. enamel and dentin) may influence sealing ability.
• Different adhesive systems (etch-and-rinse vs. self-etching) possess distinct bonding mechanisms.

Purpose of the Study:

• To evaluate the impact of adhesive application solely to enamel on marginal microleakage.
• To compare the microleakage of composite restorations using different etch-and-rinse and self-etching adhesive systems.
• To investigate if applying adhesive to both enamel and dentin affects microleakage differently than enamel-only application.

Main Methods:

• Standardized cavities were prepared in bovine incisors.
• Four adhesive systems (two etch-and-rinse, two self-etching) were applied to enamel only or to enamel and dentin.
• Composite resin restorations were placed, followed by dye immersion and spectrophotometric analysis of microleakage.
• Statistical analysis included ANOVA and Tukey's tests.

Main Results:

• Etch-and-rinse adhesives demonstrated significantly lower microleakage than self-etching adhesives.
• Adper Prompt (self-etching) exhibited the highest microleakage.
• Clearfil SE Bond showed reduced microleakage when applied to the entire cavity (enamel and dentin) compared to enamel-only application.
• No significant difference in microleakage was observed based on application mode for other systems.

Conclusions:

• Etch-and-rinse adhesives are generally superior in minimizing marginal microleakage compared to self-etching systems.
• The mode of adhesive application (enamel-only vs. whole cavity) has a limited impact on microleakage, with some exceptions.
• Bonding to dentin may not necessarily reduce microleakage in composite restorations.