New periodontal disease treatments are needed to prevent infection progression. Photodynamic therapy (PDT) is one of the greatest pledges for this purpose. It involves the use of light of specific wavelength to activate a nontoxic photosensitizing agent in the presence of oxygen for eradication of target cells, and can be used for photokilling of microorganisms. This study evaluated in vitro the photodynamic effect of 0.01% toluidine blue-O (TBO) in combination with an AlGaInP diode laser light source on Aggregatibacter actinomycetemcomitans (A.a.) and Streptococcus sanguinis (S.s.). Suspensions (2 mL) containing A.a. and S.s. at 1.5 x 108 CFU/mL concentration were prepared and divided into 3 groups: Control group (no treatment), Dye group (inoculum and TBO for 5 min) and Dye/Laser group (inoculum, TBO for 5 min and laser for 3 min). Next, a dilution for subsequent subculture in 20 mL of Trypic Soy Agar (A.a) and Brucella Agar (S.s.) in Petri dishes (Pourplate Method) was done. Incubation of A.a. in microaerophilia and S.s. in aerobiosis at 35oC for 48 h was performed for subsequent visual counting of CFU/mL. Data were analyzed by one-way ANOVA and Tukey's HSD test at 5% significance level. For both strains, the control group showed a significantly higher (p<0.05) bacterial growth (1.5 x 108 CFU/mL), while the Dye group presented no significant reduction (p>0.05) in the CFU counts. The Dye/Laser group presented a significant decrease in the CFU counts (p<0.05) compared with the Control group (61.53% for A.a. and 84.32% for S.s.). It may be concluded that PDT was effective in reducing the numbers of A.a. and S.s. in vitro.
OBJECTIVE: To evaluate the amount of debris, surface roughness and static friction in retrieved stainless steel (SS) archwires after four weeks of intraoral exposure and afterwards compare the effects of different cleaning methods.METHODS: The sample gathered seventeen as-received and eighty-five retrieved SS archwire segments, which were allocated in cleaning method groups (N=17): retrieved (RT); sodiumbicarbonate jet (SB-jet); ultrasonic cleaner (U-sonic); alcohol soaked gauze (A-gauze); and steel wool sponge (S-wool). Debris (SEM images), surface roughness (rugosimeter) and static friction(universal testing machine) were compared between as-received and retrieved SS wires and between cleaning method groups.RESULTS: Debris and surface roughness were statistically higher in RT wires than in as-received (p<0.001), whereas static friction showed no statistical difference (p>0.05). Debris were significantly lower in groups A-gauze and S-wool than in groups RT, SB-jet and U-sonic (p<0.001). Surface roughness was statistically lower in group S-wool compared to other groups (p<0.001). Static friction showed no statistical difference between cleaning methods (p>0.05).CONCLUSION: Retrieved SS archwires showed higher debris and surface roughness than asreceived, after four-weeks intraorally. A-gauze and S-wool were effective cleaning methods to control debris, but only S-wool has reduced surface roughness.
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