Résumé
Statement of the Problem: Orthodontic appliances facilitate microbial plaque accumulation and increase the chance of white spot lesions. There is a need for new plaque control methods independent of patient's cooperation
Purpose: The aim of this study was to determine the effects of incorporating copper oxide [CuO] nanoparticles on antimicrobial properties and bond strength of orthodontic adhesive
Materials and Method: CuO nanoparticles were added to the composite transbond XT at concentrations of 0.01, 0.5 and 1 wt.%. To evaluate the antimicrobial properties of composites containing nanoparticles, the disk agar diffusion test was used. For this purpose, 10 discs from each concentration of nano-composites [totally 30 discs] and 10 discs from conventional composite [as the control group] were prepared. Then the diameter of streptococcus mutans growth inhibition around each disc was determined in blood agar medium. To evaluate the shear bond strength, with each concentration of nano-composites as well as the control group [conventional composite], 10 metal brackets were bonded to the human premolars and shear bond strength was determined using a universal testing machine
Results: Nano-composites in all three concentrations showed significant antimicrobial effect compared to the control group [p< 0.001]. With increasing concentration of nanoparticles, antimicrobial effect showed an upward trend, although statistically was not significant. There was no significant difference between the shear bond strength of nano-composites compared to control group [p= 0.695]
Conclusion: Incorporating CuO nanoparticles into adhesive in all three studied concentrations added antimicrobial effects to the adhesive with no adverse effects on shear bond strength
Résumé
Introduction: This study was performed to determine the shear bond strength of rebonded mechanically retentive ceramic brackets after recycling with Erbium-Doped Yttrium Aluminum Garnet [Er:YAG] laser or sandblasting
Methods: Twenty-eight debonded ceramic brackets plus 14 intact new ceramic brackets were used in this study. Debonded brackets were randomly divided into 2 groups of 14. One group was treated by Er:YAG laser and the other with sandblasting. All the specimens were randomly bonded to 42 intact human upper premolars. The shear bond strength of all specimens was determined with a universal testing machine at a crosshead speed of 0.5 mm/min until bond failure occurred. The recycled bracket base surfaces were observed under a scanning electron microscope [SEM]. Analysis of variance [ANOVA] and Tukey tests were used to compare the shear bond strength of the 3 groups. Fisher exact test was used to evaluate the differences in adhesive remnant index [ARI] scores
Results: The highest bond strength belonged to brackets recycled by Sandblasting [16.83 MPa]. There was no significant difference between the shear bond strength of laser and control groups. SEM photographs showed differences in 2 recycling methods. The laser recycled bracket appeared to have as well-cleaned base as the new bracket. Although the sandblasted bracket photographs showed no remnant adhesives, remarkable micro-roughening of the base of the bracket was apparent
Conclusion: According to the results of this study, both Er:YAG laser and sandblasting were efficient to mechanically recondition retentive ceramic brackets. Also, Er:YAG laser did not change the design of bracket base while removing the remnant adhesives which might encourage its application in clinical practice