Shear bond strength of orthodontic bracket and adhesive materials to porcelain restorative materials
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Abstract
The purpose of this study was to compare the bond strength and location of failure of stainless steel, ceramic, and titanium orthodontic brackets of various pad designs when bonded to a dental porcelain treated with either HF acid, silane, both, or neither prior to bonding with Transbond XT composite or Fuji Ortho LC resin-modified glass ionomer. In addition, the study sought to evaluate the shear bond strength of titanium brackets to porcelain, as there is no data currently available. It was hypothesized that a certain combination of the variables would provide adequate clinical bond strength without damaging the porcelain upon debonding.
Two-hundred and eighty-eight orthodontic brackets were randomly assigned between 24 experimental groups. Forty-eight hours after their placement, brackets were debonded with an Instron Universal Testing machine at a cross head speed of 5 mm/minute. Load at failure was recorded and location of failure was observed. Multiple ANOVA and was performed to compare bond strength between all 24 groups, while Kolmogorov-Smirnov and Chi-Square tests were used to compare the location of failure between groups.
Results showed that ceramic brackets used in conjunction with composite adhesive and a porcelain surface treatment yielded the highest shear bond strength values. These values were greater than 30 MPa for all three porcelain surface treatments examined. However, such high shear bond strength values generally caused extreme fractures to the porcelain upon debonding. Comparing the independent variables, ceramic brackets produced the highest bond strength (15.51 ± 12.79 MPa), followed by titanium (10.31 ± 6.17 MPa), and then stainless steel (4.30 ± 3.55 MPa). The Transbond XT composite produced higher shear bond strengths (14.87 ± 10.43 MPa) than the Fuji Ortho LC resin-modified glass ionomer (5.21 ± 5.35 MPa). The joint use of both HF acid and silane produced the highest shear bond strength (14.88 ± 9.43 MPa), while the use of no porcelain surface treatment resulted in the lowest shear bond strength (3.56 ± 4.80 MPa). The individual use of either HF acid or silane produced similar shear bond strengths (10.96 ± 9.19 and l0.76 ± 10.36 MPa respectively).
Description
Thesis (M.S.D.)--Boston University, Henry M. Goldman School of Dental Medicine, 2002.
Includes bibliographical references (leaves 155-158).
Includes bibliographical references (leaves 155-158).
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This work is being made available in OpenBU by permission of its author, and is available for research purposes only. All rights are reserved to the author.