Wetting properties and critical micellar concentration of benzalkonium chloride mixed in sodium hypochlorite.
BACKGROUND
The purposes of the present study were to (1) assess the effect of the addition of benzalkonium chloride to sodium hypochlorite on its wetting properties, contact angle, and surface energy; (2) determine the critical micellar concentration of benzalkonium chloride in sodium hypochlorite; and (3) investigate the influence of addition of benzalkonium chloride on the free chlorine level, cytotoxicity, and antiseptic properties of the mixture.


METHODS
Solutions of benzalkonium chloride, with concentrations ranging from 0%-1%, were mixed in 2.4% sodium hypochlorite and tested as follows. The wetting properties were investigated by measuring the contact angle of the solutions on a nondehydrated dentin surface by using the static sessile drop method. The pending drop technique was subsequently used to determine the surface energy of the solutions. The critical micellar concentration of benzalkonium chloride mixed in sodium hypochlorite was calculated from the data. When 2.4% NaOCl was mixed with benzalkonium chloride at the critical micellar concentration, 3 parameters were tested: free chloride content, cytotoxicity, and antibacterial effects against Enterococcus faecalis.


RESULTS
The contact angle (P < .001) as well as the surface energy (P < .001) significantly decreased with increasing benzalkonium chloride concentrations. The critical micellar concentration of benzalkonium chloride in sodium hypochlorite was 0.008%. At this concentration, the addition of benzalkonium chloride had no effect on the free chlorine content, cytotoxicity, or antibacterial efficiency of the mixture.


CONCLUSIONS
The addition of benzalkonium chloride to sodium hypochlorite at the critical micellar concentration reduced the contact angle by 51.2% and the surface energy by 53.4%, without affecting the free chloride content, cytotoxicity, or antibacterial properties of the mixture.
Laboratoire Biologie Santé et Nanosciences, UFR Odontologie de Montpellier 1, Montpellier, France. bukietf@gmail.com
Frédéric
F
Bukiet
Guillaume
G
Couderc
Jean
J
Camps
Hervé
H
Tassery
Frederic
F
Cuisinier
Imad
I
About
Anne
A
Charrier
Nadine
N
Candoni
D000704:Analysis of Variance; D000891:Anti-Infective Agents, Local / Q000737:chemistry; D001548:Benzalkonium Compounds / Q000737:chemistry* / Q000633:toxicity; D002713:Chlorine / Q000032:analysis; D013293:Enterococcus faecalis / Q000187:drug effects; D005347:Fibroblasts / Q000187:drug effects; D006801:Humans; D008823:Micelles; D018915:Root Canal Preparation; D012973:Sodium Hypochlorite / Q000737:chemistry* / Q000633:toxicity; D018709:Statistics, Nonparametric; D013500:Surface Tension; D007507:Therapeutic Irrigation; D017155:Wettability; D014906:Wetting Agents / Q000737:chemistry / Q000633:toxicity
D000891:Anti-Infective Agents, Local; D001548:Benzalkonium Compounds; D008823:Micelles; D014906:Wetting Agents; D002713:Chlorine; D012973:Sodium Hypochlorite