Bonding orthodontic brackets to porcelain using different adhesives/enamel conditioners: a comparative study.
OBJECTIVE
To evaluate the use of new adhesive/primer materials, including an experimental self-etch primer and a cyanocrylate adhesive, to enhance the shear strength of orthodontic brackets bonded to porcelain surfaces.


METHODS
Sixty porcelain maxillary central incisor teeth were used. The teeth were randomly divided into four groups: group 1, teeth were etched with 37% phosphoric acid and the brackets were bonded with a composite adhesive; group 2, teeth were microetched, hydrofluoric acid and silane applied, and then the brackets were bonded with a composite adhesive; group 3, an acid-etch primer was used, then the brackets were bonded with the same composite adhesive as in the first 2 groups; group 4, teeth were etched with 35% phosphoric acid and the brackets were bonded with the cyanoacrylate adhesive.


RESULTS
The analysis of variance comparing the groups tested (F = 9.446) indicated that there was a significant difference between the 4 groups. The cyanoacrylate adhesive had the lowest shear bond strength (mean = 1.7 +/- 2.1 MPa), followed by the conventional bonding using a 37% phosphoric acid etch and composite (mean = 2.1 +/- 1.2 MPa). The use of Transbond after microetching, with the application of hydrofluoric acid and silane, provided the highest shear bond strength (mean = 5.5 +/- 2.7 MPa). Transbond used with the acid etch-primer had a lower bond strength (mean = 3.8 +/- 2.5 MPa), but was not significantly different from the microetch/hydrofluoric acid/silane group.


CONCLUSIONS
The results indicated that the use of a phosphoric acid etch with either a cyanoacrylate or composite adhesive to bond orthodontic brackets to porcelain surfaces produced significantly lower shear bond strength. Self-etch primers produced higher but less consistent shear bond strength for bonding orthodontic brackets. The most reliable bonding procedure to porcelain surfaces is through microetching with the use of hydrofluoric acid and a silane coupler before bonding, but this also produces the greatest damage to the porcelain surface.
Bishara
Samir E
SE
Department of Orthodontics, College of Dentistry, University of Iowa, 220 Dental Science S, Iowa City, IA 52242-1001, USA Linda-keller@uiowa.edu
Ajlouni
Raed
R
Oonsombat
Charuphan
C
Laffoon
John
J
D000134:Acid Etching, Dental / Q000379:methods*; D020906:Air Abrasion, Dental; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry; D003487:Cyanoacrylates / Q000737:chemistry; D001840:Dental Bonding; D003743:Dental Enamel; D003776:Dental Porcelain / Q000737:chemistry*; D006801:Humans; D006858:Hydrofluoric Acid / Q000737:chemistry; D008422:Materials Testing; D016910:Orthodontic Brackets; D010756:Phosphoric Acids / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry*; D033081:Shear Strength; D012821:Silanes / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties
D003188:Composite Resins; D003487:Cyanoacrylates; D010756:Phosphoric Acids; D019279:Resin Cements; D012821:Silanes; C449140:Smartbond; D003776:Dental Porcelain; C065742:Transbond; D017438:Bisphenol A-Glycidyl Methacrylate; D006858:Hydrofluoric Acid