Effects of thermomechanical and thermocycling on the shear bond strength of brackets to bovine enamel bonded with conventional and self-etching adhesive systems

Abstract

Several adhesive systems have been developed in the last decade. T<span lang="EN-US"><span lang="EN-US">he aim of the current study was to evaluate the shear bond strength of orthodontic brackets bonded with conventional primers or self-etching primers, artificially aged by means of thermocycling and thermomechanical procedures.90 bovine incisors were used in the investigation. The roots were sectioned in the amelo-cementary junction. </span></span>All samples were randomly divided in 2 groups ( n= 45), according to the primer used for bracket bonding. XT Group–hydrophobic conventional primer (Transbond XT, 3M unitek, Monrovia, Calif); SEP Group –self-etching primer (Transbond Plus SEP, 3 M Unitek, Monrovia, Calif). All specimens were bonded with XT Transbond resin adhesive (3 M Unitek, Monrovia, Calif). A Universal Testing Machine EMIC DL2000 (EMIC Equip. Sist. Ensaio Ltda., São José dos Pinhais, PR, Brazil) was used for the collection of the values of SBS resistance. The results of the current study were: (Prompt L-Pop 1.72±0.13 MPa; Clearfil SE Bond 1.75±0.19 MPa; FL Bond 1.71±0.22 MPa; One-Up Bond 1.77±0.14 MPa; XT Control 10.5±0.86 MPa). In conclusion: the number of cycles in thermal and thermo mechanical cycling did not influence shear bond strength values for any of the primers tested;SEP Transbond Plus showed the greatest values for bond strength of orthodontic brackets.

Effect of different bonding protocols on degree of monomer conversion and bond strength between orthodontic brackets and enamel

“…However, in spite of these values, no fractures were observed in enamel according to the Adhesive Remnant Index. Torres et al, 26 using similar Table 7. Power of the polymerization units according to the manufacturer and the calibration in the radiometer.…”

“…15 When comparing adhesive resistance between the conventionally treated groups (ATxt) and the orthodontic self-conditioning system (Tse) for each polymerization units, no difference was found, thus corroborating the findings of previous studies. 12,26,31 No previous study compared ATxt and Tse surface treatments submitted to 3-second curing.…”