COMPARISON OF SHEAR BOND STRENGTH OF METAL AND CERAMIC ORTHODONTIC BRACKETS AFTER ADDING NANOPARTICLES OF SILVER

Objective: To evaluate effect of nanoparticles of silver (NAg) added on Nano-Bond adhesive system and its effect on shear bond strength of brackets attached to enamel.
Materials and methods: Thirty extracted premolar teeth for orthodontic reasons were divided into two groups; First group metal brackets and second group the ceramic brackets were bonded by Nano-Bond adhesive system containing (NAg) with concentration 0.05%. Every group was further subdivided into 2subgroups with 5 teeth each; Groups A1, B1 (Teeth not subjected to thermocycling and cyclic loading), Groups A2, B2 [(Teeth subjected to thermocycling (500cycles) and cyclic loading (90N, 0.8-1 cycles/sec. 100,000 cycles)]
Enamel etched then the adhesives were applied to the entire enamel surface according to bonding agent containing (NAg) or not, then light cured for 10 seconds with LED. The base of brackets were filled by nano-filled composite resin and placed on the tooth and cured by LED for 40 seconds. The recorded values of bond strengths in (MPa) were collected, tabulated and statistically analyzed. One way analysis of variance (ANOVA) and Tukey’s tests were used for testing the significance between the means of tested groups which are statistically significant when the
P value ≤ 0.05.
Results: shear bond strength of metal brackets bonded by Nano-Bond adhesive containing nanoparticles of silver (NAg) (Group A) was significantly higher than shear bond strength of ceramic brackets (group B).
Conclusions: The adhesive shear strengths are high for metal bracket bonded by Nano-Bond adhesive system containing nanoparticles of silver (NAg) with concentration 0.05% than ceramic bracket.