[Effect of bonding materials and methods on microleakage around the edge of stainless-steel brackets: an in vitro study].
OBJECTIVE
To observe and compare the effect of different types of adhesive materials and different types of etching methods on microleakage around bonded metal brackets.


METHODS
36 healthy premolars extracted for orthodontic reason were selected in the study. The samples were divided into three groups, 12 in each. Group A was etched with 37% phosphate and bonded with Jingjin adhesive; Group B was with 37% phosphate+3M Transbond; Group C was self-etching primer+3M Transbond. All samples were thermalcycled for 500 times, then put into 1% methylenum solution for 24 hours. Microleakage of samples was observed under stereomicroscope. Multiple comparison and Student t test were used for the comparison of data samples(alpha=0.05).


RESULTS
(1) Significant difference of microleakage was found among three groups (F=22.462, P<0.01); Multiple comparison showed no significant difference between Group A and Group B (P>0.05), significant differences of microleakage were found between group A and C (P<0.05), group B and C (P<0.05), respectively. (2) Significant differences between occlusal microleakage and gingival microleakage were found in group A (P<0.05), group B (P<0.01) and group C (P<0.01), respectively.


CONCLUSIONS
(1) The type of adhesive had no effect on microleakage. (2)Different etching methods are relevant to microleakage, the microleakage of self-etching groups is much more than that of phosphate-etching groups. (3) Gingival microleakage is significantly larger than occlusal microleakage.
Li
Zheng-ming
ZM
Department of Dentistry, Nanshan People's Hospital of Shenzhen City, China. lizhm2000@yahoo.com.cn
Chen
Si-han
SH
Liu
Xin-qiang
XQ
Chen
Jie
J
Li
Ning-yi
NY
D000134:Acid Etching, Dental; D001641:Bicuspid; D017438:Bisphenol A-Glycidyl Methacrylate; D001840:Dental Bonding; D003738:Dental Cements; D003763:Dental Leakage; D006801:Humans; D008422:Materials Testing; D013193:Stainless Steel
D003738:Dental Cements; D013193:Stainless Steel; C065742:Transbond; D017438:Bisphenol A-Glycidyl Methacrylate