Shear bond strength of different adhesives tested in accordance with DIN 13990-1/-2 and using various methods of enamel conditioning.
OBJECTIVE
The purpose of this work was to analyze the shear bond strength (SBS) of different adhesives for orthodontic brackets in accordance with DIN 13990-1/-2, also taking into consideration potential effects arising from different scenarios of enamel conditioning and specimen storage.


METHODS
A total of 390 experiments were performed, with groups of 10 specimens subjected to identical treatments. Three adhesives were tested: Transbond™ XT (3M Unitek, Monrovia, USA), Beauty Ortho Bond (Shofu, Kyoto, Japan), and Fuji Ortho LC (GC Europe, Leuven, Belgium). SBS was evaluated separately at the bracket-adhesive and adhesive-enamel interfaces, as well as the total (enamel-adhesive-bracket) interface. The brackets were metal brackets for upper right central incisors (Discovery® from Dentaurum, Ispringen, Germany). A universal testing machine (Zwick Z010, Ulm, Germany) was used for testing the SBS after 15 min, or after storage in distilled water at 37 °C for 24 h, or after 24 h followed by 500 thermocycles alternating between 5 and 55 °C.


RESULTS
Transbond™ XT produced the highest levels of SBS. The least favorable performance was observed with Fuji Ortho LC after enamel conditioning with 10 % polyacrylic acid. Thermocycling did not have a significant influence.


CONCLUSIONS
Transbond™ XT and Beauty Ortho Bond (but not Fuji Ortho LC) yielded levels of SBS adequate for clinical application (≥ 7 MPa).
Center for Dental and Craniofacial Sciences, Department of Orthodontics, Dentofacial Orthopedics and Pedodontics, Charité - Universitätsmedizin Berlin, CC3, Aßmannshauser Str. 4-6, 14197, Berlin, Germany.
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Richter
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PG
Jost-Brinkmann
D000134:Acid Etching, Dental; D000268:Adhesiveness; D001840:Dental Bonding / Q000379:methods; D003738:Dental Cements / Q000737:chemistry* / Q000592:standards*; D003743:Dental Enamel / Q000737:chemistry*; D045662:Dental Etching / Q000379:methods*; D003813:Dentistry / Q000592:standards; D004356:Drug Storage; D017408:Guidelines as Topic; D006801:Humans; D007180:Incisor / Q000737:chemistry*; D038622:Internationality; D008422:Materials Testing / Q000592:standards*; D033081:Shear Strength; D013314:Stress, Mechanical; D013499:Surface Properties
D003738:Dental Cements