Comparison of the bond strength of stainless steel orthodontic brackets bonded to crown porcelains.
BACKGROUND
The bond strengths and mode of failure of stainless steel orthodontic brackets bonded to the newer all-ceramic crown systems has not been fully investigated.


OBJECTIVE
To compare the shear-peel bond strengths and modes of failure of stainless steel Begg orthodontic brackets bonded to all-ceramic crown systems (Finesse, Empress II) and a conventional feldsphatic crown porcelain (Vita Omega 900).


METHODS
Fifteen flat-surface discs of three crown porcelains (Finesse, Vita Omega 900, Empress II) were made and mounted in acrylic moulds. The discs were pumiced, etched with phosphoric acid, primed with silane, and a flat stainless steel Begg bracket bonded to each disc with a chemical cure composite resin (Unite Bond). The discs were stored for one week in water and debonded with a sheer-peel load in an Instron uniaxial testing system with a crosshead speed of 0.5 mm/min. The composite remnants on the ceramic surfaces were classified using the Adhesive Remnant Index (ARI).


RESULTS
The bond strength of Finesse (15.03 +/- 1.90 MPa) was significantly greater (p < 0.001) than Vita Omega 900 11.51 +/- 2.35 MPa) and Empress II (11.12 +/- 1.78 MPa). There were no significant differences among the ARI scores. The mode of failure was a mixture of adhesive and cohesive failure.


CONCLUSIONS
The results indicate that the bond strengths of stainless steel orthodontic brackets bonded to Finesse and Empress II porcelains are clinically acceptable.
Chay
Siew Han
SH
Faculty of Dentistry, University of Singapore, Singapore. mjenner2@yahoo.com
Wattanapayungkul
Pranee
P
Yap
Adrian U Jin
AU
Loh
Poey Ling
PL
Chung
Sew Meng
SM
D000134:Acid Etching, Dental; D000268:Adhesiveness; D000538:Aluminum Silicates / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry; D003442:Crowns; D001840:Dental Bonding; D003776:Dental Porcelain / Q000737:chemistry*; D006801:Humans; D018020:Lithium Compounds / Q000737:chemistry; D008422:Materials Testing; D016910:Orthodontic Brackets; D010756:Phosphoric Acids / Q000737:chemistry; D017680:Potassium Compounds / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D033081:Shear Strength; D012821:Silanes / Q000737:chemistry; D017640:Silicates / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D013193:Stainless Steel / Q000737:chemistry*; D013314:Stress, Mechanical; D013499:Surface Properties
D000538:Aluminum Silicates; D003188:Composite Resins; C118557:Empress 2; D018020:Lithium Compounds; D010756:Phosphoric Acids; D017680:Potassium Compounds; D019279:Resin Cements; D012821:Silanes; D017640:Silicates; C110711:vita omega; D003776:Dental Porcelain; C016447:feldspar; D013193:Stainless Steel; D012822:Silicon Dioxide; C037884:finesse; C073908:Unite resin; C005144:pumice