METHODS: Dissolution kinetics of CHX-HMP were firstly explored using spectroscopy and a colorimetric phosphate assay. Elastomeric ligatures were categorized into 3 groups-acetone-conditioned, ethanol-conditioned, and as received-and were then immersed in 5 mM CHX-HMP suspension or 5 mM chlorhexidine digluconate solution and rinsed. CHX release was measured over 8 weeks, and the effects of conditioning and immersion on elastomeric force and extension at rupture and surface topography were investigated.
RESULTS: CHX-HMP exhibited a gradual equilibration that had not reached equilibrium within 8 weeks, releasing soluble CHX and a mixture of polyphosphate and orthophosphate. CHX digluconate-treated ligatures showed no CHX release, whereas CHX-HMP-treated ligatures showed varying degrees of release. As received, CHX-HMP-treated ligatures showed a modest release of CHX up to 7 days. Acetone conditioning did not enhance CHX-HMP uptake or subsequent CHX release and caused a deterioration in mechanical properties. Ethanol conditioning enhanced CHX-HMP uptake (6×) and led to a sustained CHX release over 8 weeks without affecting mechanical properties.
CONCLUSIONS: Within the inherent limitations of this in-vitro study, CHX-HMP led to a sustained release of CHX from orthodontic elastomeric ligatures after ethanol conditioning. Conditioned and coated elastomeric ligatures may ultimately find application in the prevention of white spot lesions in orthodontic patients.
METHODS AND RESULTS: Ag-NPs were synthesized using a chemical reduction method and characterized with respect to their surface plasmon resonance, surface morphology via transmission electron microscopy (TEM) and dynamic light scattering (DLS). The bacterial surface was targeted using 20 nm Ag-NPs conjugated with an anti-protein A antibody. Labelled bacteria were irradiated with blue visible laser at 2·04 W/cm2 . The antibacterial activity of functionalized Ag-NPs was investigated by fluorescence microscopy after irradiation, and morphological changes in S. aureus after laser treatment were assessed using scanning electron microscopy (SEM). The laser-irradiated, functionalized Ag-NPs exhibited significant bactericidal activity, and laser-induced bacterial damage was observed after 10 min of laser irradiation against S. aureus. The fluorescence microscopic analysis results supported that bacterial cell death occurred in the presence of the functionalized Ag-NPs.
CONCLUSIONS: The results of this study suggest that a novel method for the preparation of functionalized nanoparticles has potential as a potent antibacterial agent for the selective killing of resistant disease-causing bacteria.
SIGNIFICANCE AND IMPACT OF THE STUDY: This study shows that Ag-NPs functionalized with a specific antibody, could be used in combination with laser radiation as a novel treatment to target resistant bacterial and fungal pathogens with minimal impact on normal microflora.
MATERIALS AND METHODS: Matured, healthy and disease-free leaves of Eucalyptus globulus were collected. The leaves were washed under tap water and finally dried in an oven at a temperature of 45°C for 48 hours. The dried plants were ground in an electric blender to make them into a powder. The powder was mixed with 100% ethanol and kept it inside a shaker overnight at 35°C. The mixture was centrifuged for 10 minutes at 2,500 rpm. Three different concentrations (10%, 50%, and 100% v/v) were used as antibacterial agents. Chlorhexidine (0.2%) was considered as positive control and dimethyl formamide was considered as negative control against P. gingivalis and A. actinomycetemcomitans. The disc diffusion method was used to determine the extract's antibacterial activity against the test organisms. A digital Vernier caliper was used to measure the diameter of antibacterial activity showing the zone of inhibition in millimeters.
RESULTS: Eucalyptus globulus with 100% concentration showed a maximum zone of inhibition against A. actinomycetemcomitans and P. gingivalis (5.38 ± 0.32 mm, 4.82 ± 0.11 mm) followed by 50% and 10% accordingly. The negative control of dimethyl formamide showed a zone of inhibition of 0.48 ± 0.96 mm and 0.63 ± 0.20 mm against A. actinomycetemcomitans and P. gingivalis. The positive control of 0.2% chlorhexidine showed a zone of inhibition of 8.46 ± 1.02 mm and 7.18 ± 0.54 mm against A. actinomycetemcomitans and P. gingivalis. The ANOVA test showed a highly significant antibacterial efficacy in 0.2% chlorhexidine and 100% concentration Eucalyptus globulus.
CONCLUSION: A significant maximum zone of inhibition against A. actinomycetemcomitans and P. gingivalis was showed by 100% concentration of Eucalyptus globulus.
CLINICAL SIGNIFICANCE: Other than the systemic diseases treatment, Eucalyptus globulus also serves as an effective promising alternative to antibiotics in the prevention of oral infections because of the natural phytochemicals existing in them.