The effect of benzalkonium chloride additions to AH Plus sealer. Antimicrobial, physical and chemical properties

Abstract

Objectives: The aim of this study was to determine the antimicrobial and antibiofilm activities and

physicochemical properties of AH Plus sealer mixed with different concentrations of benzalk- onium chloride (BC).

Methods: AHPluswas testedaloneandmixedwith1%,2%and3%ofBC.Theantimicrobialandantibiofilm

activities of the sealers against Enterococcus faecalis were evaluated by the direct contact test (DCT) and by

confocallaser scanningmicroscopy, respectively.Setting time,flow and solubilitywere assessed according

to ANSI/ADA specifications. Microhardness and contact angle tests were also performed. The chemical

changes of the sealers were evaluated by X-ray diffraction analysis, and both Fourier transform infrared

spectroscopy (FT-IR) and attenuated total reflectance Fourier transform infrared (ATR FT-IR).

Results: AH Plus + 3% BC was the only sealer to promote total elimination of E. faecalis and the

biovolume in this group was significantly lower than in the rest of the sealers ( p > 0.05). The physical

propertiesofthe sealerswereaccording totheANSI/ADAspecifications.Themicrohardnessdecreased

significantly when BC was added and a significant reduction in contact angle was obtained when

incorporating 2% and 3% BC ( p < 0.05). No phase changes were observed with the modified sealers.

Conclusions: The addition of 2% or higher concentrations BC to AH Plus showed antimicrobial and

antibiofilm activities without affecting the properties specified in ANSI/ADA standards. However,

additives to the root canal sealer altered other physical and chemical properties that are not

commonly found in the literature to evaluate filling materials.

Clinical significance: The present study highlights that the antimicrobial properties of AH Plus can

be significantly improved with the addition of BC. Testing beyond what is specified in standards

may be indicated.