title: Determination of para-chloroaniline and reactive oxygen species in chlorhexidine and chlorhexidine associated with calcium hydroxide.
abstract: The aim of this study was to determine whether para-chloroaniline (PCA) and/or reactive oxygen species (ROS) are generated by chlorhexidine (CHX) alone or after CHX is mixed with calcium hydroxide at different time points. Mass spectrometry was performed to detect PCA in samples of 0.2% CHX and Ca(OH)2 mixed with 0.2% CHX. High-performance liquid chromatography was used to confirm the presence of CHX in the mixture with Ca(OH)2. The samples were analyzed immediately after mixing and after 7 and 14 days. During the intervals of the experiment, the samples were maintained at 36.5 degrees C and 95% relative humidity. PCA was detected in the 0.2% CHX solution after 14 days. The mixture of CHX with Ca(OH)2 liberated ROS at all time points, but no traces of CHX were present in the mixture as a result of immediate degradation of the CHX.
authors.affiliation: Department of Restorative Dentistry, Dental School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP.
authors.forename: Luiz Eduardo
authors.initials: LE
authors.lastname: Barbin
authors.forename: Paulo César
authors.initials: PC
authors.lastname: Saquy
authors.forename: Débora Fernandes Costa
authors.initials: DF
authors.lastname: Guedes
authors.forename: Manoel Damião
authors.initials: MD
authors.lastname: Sousa-Neto
authors.forename: Carlos
authors.initials: C
authors.lastname: Estrela
authors.forename: Jesus Djalma
authors.initials: JD
authors.lastname: Pécora
mesh_terms: D000814:Aniline Compounds / Q000032:analysis / Q000737:chemistry*; D002126:Calcium Hydroxide / Q000737:chemistry*; D002710:Chlorhexidine / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D006801:Humans; D006813:Humidity; D013058:Mass Spectrometry; D008422:Materials Testing; D017382:Reactive Oxygen Species / Q000032:analysis / Q000737:chemistry*; D012388:Root Canal Irrigants / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization; D013696:Temperature; D013997:Time Factors
chemical_list: D000814:Aniline Compounds; D017382:Reactive Oxygen Species; D012388:Root Canal Irrigants; D002126:Calcium Hydroxide; D002710:Chlorhexidine; C004658:4-chloroaniline