Antimicrobial activity of different disinfectants against cariogenic microorganisms

Abstract The aim of this study was to assess the in vitro antimicrobial effects of chlorhexidine digluconate (CHX), polyhexamethylene biguanide (PHBM), and octenidine dihydrochloride (OCT) on cariogenic microorganisms by using their minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). CHX, PHBM, and OCT were diluted in distilled water to the final test concentrations. Using the in-tube dilution method, Streptococcus mutans, Lactobacillus acidophilus, Lactobacillus rhamnosus, and Actinomyces viscosus were cultivated on blood agar and Mueller-Hinton broth (MHB) at 37°C for 48 h. They were read using a spectrophotometer to detect MIC. To determine MBC, samples in the range of the turbidity threshold after 24 h were transferred onto blood agar and evaluated for growth after 24 h. Different MICs and MBCs were observed in all disinfectants against each microorganism. The lowest MIC and MBC against S. mutans (60 mg/L) were obtained from PHBM. The lowest values against L. rhamnosus (15 mg/L, 30 mg/L), A. viscosus (30 mg/L), and L. acidophilus (15 mg/L, 30 mg/L) were determined by OCT. PHBM and OCT have the potential to be replaced with CHX because they were effective against cariogenic microorganisms.

The Effects of Enamel Matrix Proteins and Dentin Collagen on the Attachment of Periodontal Ligament Cells.

Background: The aim of this study was to evaluate the effect of enamel matrix proteins (EMP) and dentin collagen on the attachment of periodontal ligament cells to the root surfaces. Methods: Eighty-four root slices were obtained from forty-two lower anterior teeth that had been extracted due to the periodontal disease. The root slices were subjected to one of the following treatments: 1) control group 2) EDTA demineralization + EMP, 3) dentin collagen, 4) EDTA demineralization + dentin collagen. Periodontal ligament (PDL) cells (105/ml) were seeded and incubated for two hours on surfaces of the roots in each group. Following the incubation the numbers of the attached cells were calculated by colorimetric assay and the morphologies of the cells were evaluated by scanning electron microscopy (SEM). One-way ANOVA was used for statistical analysis (p=0.05). Results: No significant difference was found among the groups regarding the number of attached cells (p>0.05). However, the mean number of the attached cells was highest in the 2nd Group (EDTA demineralization + EMP), while it was lowest in Group 3 (dentin collagen). SEM evaluation of the dentin specimens revealed that the EMPs treated specimens exhibited elongated fibroblasts with filopodial extensions while the cells in the control and dentin collagen treated groups were round with thin and short filopodia. Conclusion: In this study, the EMPs were found effective in the attachment of cells on the root surface when compared to dentin collagen.