Chlorhexidine added to different adhesive systems - Assessment of antibacterial activity and bond strength

Bruna Caroline De Oliveira Lima,Julio Katuhide Ueda,Marcio José Mendonça,Rafael Andrade Menolli,João Vitor Oribka Roque,Thayna Carolina Zeni,Veridiana Camilotti

doi:10.33448/rsd-v11i3.25785

Bruna Caroline De Oliveira Lima, Julio Katuhide Ueda + Show 5 more

Open Access

https://doi.org/10.33448/rsd-v11i3.25785

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Abstract

This study aimed to assess the effects of adding chlorhexidine (CHX) to different adhesive systems on antibacterial activity and bond strength after 24 hours and 30 days under in vitro conditions. A total of 210 bovine incisor crowns and divided into three groups, based on the adhesive system: Single Bond Plus (SB), Clearfil SE Bond (CL), and AdheSE Primer and Bond (AD). All groups were subdivided by CHX concentration (n=7): no CHX, CHX applied before the adhesive (CPA), and the adhesive incorporated with 0.5% CHX, 1.0% CHX, and 2.0% CHX. The micro shear test was conducted on one-half of the specimens after 24 hours, and on the other half after 30 days. Antibacterial activity was evaluated using the agar diffusion test with Streptococcus mutans. The bond strength variable was assessed using the factorial analysis of variance for repeated measurements, whereas the variable of the bacterial halo size was subjected to the Kruskal–Wallis nonparametric test. The significance level was 5% for both tests. The qualitative variable of fracture pattern was assessed by descriptive statistical analysis. Thus, CHX concentration of 2% (10.80 ±2.83) and CPA (9.95 ±1.47) (p >0.05) helped to increase the bond strength values for most adhesive systems, whereas CL had the highest bond strength values. The CL adhesive system also presented the best results in the antibacterial test with S.mutans.

Highlights

The total acid etching technique used by etch-and-rinse adhesive systems promotes micromechanical retention between dentin collagen, adhesive monomer, and composite resin
Changing the CHX concentration or using CHX applied before the adhesive (CPA) after 24 hours did not change the values obtained for the AD adhesive
The Single Bond Plus (SB) adhesive systemfor CHX concentration of 2% had significantly lower results than those of the other adhesive systems

Summary

Introduction

The total acid etching technique used by etch-and-rinse adhesive systems promotes micromechanical retention between dentin collagen, adhesive monomer, and composite resin. It thereby forms a hybrid layer or a dentin/resin interdiffusion zone. Despite their bonding effectiveness, these adhesives cause discrepancies between the acid demineralization depth and monomer diffusion. Dentin that is demineralized and not infiltrated by the adhesive may drive the action of matrix metalloproteinase (MMP) enzymes responsible for the long-term degradation of the hybrid layer (Breschi et al, 2010; Hajizadeh et al, 2013; Araujo et al, 2015). The entire extent of the demineralized dentin is infiltrated by resin monomers and decreases the action of MMPs (Strobel et al, 2015)

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