In vitro evaluation of benzalkonium chloride in the preservation of adhesive interfaces.
Inhibition of endogenous dentin matrix metalloproteinases (MMPs) by benzalkonium chloride (BAC) decreases collagen solubilization and may help improve resin-dentin bond stability.


OBJECTIVE
This study evaluated the resin-dentin bond stability of experimental adhesive blends containing BAC and the stability of dentin matrices by assessing the mass loss and collagen solubilization from dentin beams pretreated with BAC.


METHODS
Twenty-five healthy molars were used for the bond strength evaluation of a two-step etch-and-rinse adhesive (Adper Single Bond Plus, SB) modified with BAC or not. The following groups were tested: 1) SB with no inhibitor (control); 2) topical 2.0% chlorhexidine + SB; 3) 1.0% BAC etchant + SB; 4) 0.5% BAC-SB; and 5) 1.0% BAC-SB. Microtensile bond strength (μTBS) and failure mode distribution under standard error of the mean were evaluated after 24 hours and six months of storage in artificial saliva (AS). A two-way analysis of variance and Tukey test with a significance level of p<0.05 was used for data analysis. In addition, 30 completely demineralized dentin beams from human molars were either dipped in deionized water (DW, control) or dipped in 0.5% and 1.0% BAC for 60 seconds, and then incubated in AS. Collagen solubilization was assessed by evaluating the dry mass loss and quantifying the amount of hydroxyproline (HYP) released from hydrolyzed specimens after four weeks of incubation.


RESULTS
The control group demonstrated lower μTBS than some of the experimental groups containing BAC at 24 hours and six months (p<0.05). When BAC was incorporated into the adhesive blend in concentrations of 0.5% and 1.0%, no reduction in dentin bond strength was observed after six months (p<0.05). Less mass loss and HYP release was seen for dentin matrices pretreated with BAC relative to the control pretreated with DW (p<0.05).


CONCLUSIONS
This in vitro study demonstrates that BAC contributes to the preservation of resin-dentin bonds by reducing collagen degradation.
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Sabatini
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Kim
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Ortiz Alias
D001548:Benzalkonium Compounds / Q000627:therapeutic use*; D002710:Chlorhexidine / Q000627:therapeutic use; D003094:Collagen / Q000187:drug effects; D003188:Composite Resins / Q000627:therapeutic use; D001840:Dental Bonding / Q000379:methods*; D003738:Dental Cements / Q000627:therapeutic use; D019232:Dental Restoration Failure; D003793:Dental Restoration, Permanent / Q000379:methods; D003799:Dental Stress Analysis; D003804:Dentin / Q000187:drug effects; D006801:Humans; D066298:In Vitro Techniques
C554641:Adper single bond 2; D001548:Benzalkonium Compounds; D003188:Composite Resins; D003738:Dental Cements; D003094:Collagen; D002710:Chlorhexidine