# Effect of surface preparation methods on the shear bond strength of universal and self-etch adhesive systems: an in vitro study

## TL;DR

This study examines how different surface preparation methods affect the bond strength of dental adhesives on enamel and dentin.

## Contribution

The study compares three surface preparation methods with different adhesives to determine their impact on bond strength and failure patterns.

## Key findings

- Kuraray Clearfil SE Bond showed the highest bond strength on enamel with air abrasion.
- Fine grit finishing achieved the highest bond strength on dentin across all adhesives.
- SEM/EDS analysis revealed adhesive failures were most common, with occasional cohesive failures in high-strength cases.

## Abstract

To assess the impact of three smear layer preparation methods on shear bond strength (SBS) to enamel and dentin, using two universal adhesives (Tetric N-Bond Universal, 3M Single Bond Universal) and one two-step self-etch adhesive (Kuraray Clearfil SE Bond).

Ninety extracted premolars were assigned to enamel and dentin groups (n = 45 each) and prepared with coarse grit (120), fine grit (600) silicon carbide paper, or air abrasion (Aluminium Oxide for enamel, Sylc for dentin). Surfaces were bonded with one of the adhesives and restored with composite. Enamel was treated in an etch-and-rinse mode, dentin in self-etch mode. SBS was tested using a universal testing machine. Failure surfaces were examined under SEM to assess fracture morphology and EDS to determine elemental composition. Data were analyzed using two-way ANOVA/Tukey's post-hoc test and Weibull statistics (P ≤ 0.05).

In enamel, SBS generally increased from coarse to fine to air abrasion. Kuraray Clearfil SE Bond yielded the highest values, particularly with air abrasion (9.11 ± 0.51 MPa). In dentin, fine grit achieved the highest SBS across all adhesives, followed by air abrasion; coarse grit showed the lowest. Kuraray consistently outperformed the universal adhesives in most dentin conditions. SEM/EDS revealed predominantly adhesive failures; occasional cohesive failures in dentin (Ivoclar) and enamel (Kuraray) corresponded with higher SBS and Weibull reliability.

Both surface preparation and adhesive type significantly influence SBS. Kuraray showed superior performance and reliability, while fine grit and air abrasion enhanced bonding efficacy. SEM/EDS findings corroborated the mechanical results.

Image 1

•Surface preparation method and adhesive type significantly influence SBS.•Fine grit finishing and air abrasion improved bonding efficacy.•Chemically compatible adhesives with proper protocols improve predictability and durability of restorations.•For long lasting adhesion, match the material with the appropriate clinical protocol.

Surface preparation method and adhesive type significantly influence SBS.

Fine grit finishing and air abrasion improved bonding efficacy.

Chemically compatible adhesives with proper protocols improve predictability and durability of restorations.

For long lasting adhesion, match the material with the appropriate clinical protocol.