Comparison of Antibacterial Effects of ZnO and CuO Nanoparticles Coated Brackets against Streptococcus Mutans.
BACKGROUND
During the orthodontic treatment, microbial plaques may accumulate around the brackets and cause caries, especially in high-risk patients. Finding ways to eliminate this microbial plaque seems to be essential.


OBJECTIVE
The aim of this study was to compare the antibacterial effects of nano copper oxide (CuO) and nano zinc oxide (ZnO) coated brackets against Streptococcus mutans (S.mutans) in order to decrease the risk of caries around the orthodontic brackets during the treatment.


METHODS
Sixty brackets were coated with nanoparticles of ZnO (n=20), CuO (n=20) and CuO-ZnO (n=20). Twelve uncoated brackets constituted the control group. The brackets were bonded to the crowns of extracted premolars, sterilized and prepared for antimicrobial tests (S.mutans ATCC35668). The samples taken after 0, 2, 4, 6 and 24 hours were cultured on agar plates. Colonies were counted 24 hours after incubation. One-way ANOVA and Tukey tests were used for statistical analysis.


RESULTS
In CuO and CuO-ZnO coated brackets, no colony growth was seen after two hours. Between 0-6 hours, the mean colony counts were not significantly different between the ZnO and the control group (p>0.05). During 6-24 hours, the growth of S.mutans was significantly reduced by ZnO nanoparticles in comparison with the control group (p< 0.001). However, these bacteria were not totally eliminated.


CONCLUSIONS
CuO and ZnO-CuO nanoparticles coated brackets have better antimicrobial effect on S.mutans than ZnO coated brackets.
Dental Research Center, Dept. of Orthodontics, School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran.
Baratali
B
Ramazanzadeh
Dental Research Center, Dept. of Orthodontics, School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran.
Arezoo
A
Jahanbin
Dept. of Orthodontics, School of Dentistry, Bojnourd University of Medical Sciences, Bojnord, Iran.
Masoud
M
Yaghoubi
Dept. of Physics, Ferdowsi University of Mashhad, Mashhad, Iran.
Nasser
N
Shahtahmassbi
Dept. of Microbiology, Ghaem Hospital, Mashhad University of Medical Sciences, Mashhad, Iran.
Kiarash
K
Ghazvini
Dept. of Community Medicine and Public Health, Ghaem Hospital, Mashhad University of Medical Sciences, Mashhad, Iran.
Mohammadtaghi
M
Shakeri
Dental Research Center, Dept. of Orthodontics, School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran.
Hooman
H
Shafaee
Bracket; Nanotechnology; Streptococcus Mutans