Evaluation of an alternative technique to optimize direct bonding of orthodontic brackets to temporary crowns.
OBJECTIVE
To compare shear bond strength of different direct bonding techniques of orthodontic brackets to acrylic resin surfaces.


METHODS
The sample comprised 64 discs of chemically activated acrylic resin (CAAR) randomly divided into four groups: discs in group 1 were bonded by means of light-cured composite resin (conventional adhesive); discs in group 2 had surfaces roughened with a diamond bur followed by conventional direct bonding by means of light-cured composite resin; discs in group 3 were bonded by means of CAAR (alternative adhesive); and discs in group 4 had surfaces roughened with a diamond bur followed by direct bonding by means of CAAR. Shear bond strength values were determined after 24 hours by means of a universal testing machine at a speed of 0.5 mm/min, and compared by analysis of variance followed by post-hoc Tukey test. Adhesive remnant index (ARI) was measured and compared among groups by means of Kruskal-Wallis and Dunn tests.


RESULTS
Groups 3 and 4 had significantly greater shear bond strength values in comparison to groups 1 and 2. Groups 3 and 4 yielded similar results. Group 2 showed better results when compared to group 1. In ARI analyses, groups 1 and 2 predominantly exhibited a score equal to 0, whereas groups 3 and 4 predominantly exhibited a score equal to 3.


CONCLUSIONS
Direct bonding of brackets to acrylic resin surfaces using CAAR yielded better results than light-cured composite resin. Surface preparation with diamond bur only increased shear bond strength in group 2.
Universidade Ceuma, São Luís, Maranhão, BR.
Francilena Maria Campos Santos
FM
Dias
Department of Orthodontics, Universidade Ceuma, São Luís, Maranhão, BR.
Célia Regina Maio
CR
Pinzan-Vercelino
School of Dentistry, Universidade de São Paulo, Bauru, São Paulo, BR.
Rudys Rodolfo de Jesus
RR
Tavares
Universidade Ceuma, São Luís, Maranhão, BR.
Júlio de Araújo
Jde A
Gurgel
Universidade Ceuma, São Luís, Maranhão, BR.
Fausto Silva
FS
Bramante
Universidade Ceuma, São Luís, Maranhão, BR.
Melissa Nogueira Proença
MN
Fialho
D000134:Acid Etching, Dental / Q000379:methods; D000180:Acrylic Resins / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry; D003442:Crowns; D001840:Dental Bonding / Q000379:methods*; D045662:Dental Etching / Q000379:methods; D003764:Dental Materials / Q000737:chemistry; D003794:Dental Restoration, Temporary; D003799:Dental Stress Analysis / Q000295:instrumentation; D018130:Diamond / Q000737:chemistry; D055115:Light-Curing of Dental Adhesives / Q000379:methods; D008422:Materials Testing; D008768:Methylmethacrylates / Q000737:chemistry; D016910:Orthodontic Brackets; D011897:Random Allocation; D019279:Resin Cements / Q000737:chemistry; D033081:Shear Strength; D013314:Stress, Mechanical; D013499:Surface Properties; D013997:Time Factors
D000180:Acrylic Resins; D003188:Composite Resins; D003764:Dental Materials; D008768:Methylmethacrylates; D019279:Resin Cements; C477790:Transbond XT; C516047:Transbond XT Light Cure Adhesive Primer; C034578:Duralay; D018130:Diamond