Antibacterial effects and physical properties of glass-ionomer cements containing chlorhexidine for the ART approach

Objectives Since atraumatic restorative treatment (ART) involves removal of carious lesions with manual instruments, improvement of filling materials to guarantee greater success should be considered. This study aimed to evaluate antibacterial, physical, and bonding properties of glass-ionomer cements (GIC) containing chlorhexidine (CHX), and to determine optimal concentrations for incorporation of agents to obtain antibacterial GICs for use with the ART approach. Methods CHX diacetate combined with CHX dihydrochloride was added to control GIC powder to obtain concentration ratios of 1/0, 2/0, 3/0, 1/1, or 2/2% w/w. Antibacterial activity of each cement against Streptococcus mutans, Lactobacillus casei or Actinomyces naeslundii was examined using agar-diffusion methods, and release of CHX was analyzed by HPLC. Compressive strength, bond strength to dentin, and setting time were measured, and compared with those of control samples. Results All experimental GICs exhibited inhibition of three bacteria, but sizes of inhibition zones and concentrations of CHX released were not dependent upon CHX content. Incorporation of CHX diacetate at 2% or greater, significantly decreased compressive strength, and bond strength to dentin was adversely affected by addition of CHX diacetate at 2% or more (p<0.05, ANOVA, Fisherʹs PLSD test), although setting time was extended a little by addition of any concentrations of CHX. Significance The present results demonstrate that experimental GICs containing CHX are effective in inhibiting bacteria associated with caries, and incorporation of 1% CHX diacetate is optimal to give appropriate physical and bonding properties.