Table 1 Composition of the resins investigated

Orthocem UV (UV group)

Dentscare Ltda. (Joinville, Brazil)

-Bisphenol A Diglycidyl ether methacrylate (BisGMA): 25–35

-Triethylene glycoldimethacrylate (TEGDMA): 10–15

-Phosphate methacrylate monomer: > 2

-Silanized silicon dioxide: 45–60

-Camphorquinone: < 1

-Sodium fluoride: > 1

-Fluorescent pigment: < 0.01

-Etching with 37% phosphoric acid for 15 s;

-Continuous jet of water for 20 s;

- Oil- and moisture-free jets of air;

-Composite resin applied to the base of orthodontic accessory;

-Polymerization for 20 s (10 s mesial and 10 s distal).

Transbond XT (C group)

3M Oral Care

(Monrovia, CA, USA)

-Organic matrix: Bis-GMA and TEGDMA

-Inorganic part: silica silanized with 70 to 80% by volume

-n-dimethyl benzocaine, hexafluorphosphate

-Camphorquinone

-Etching with 37% phosphoric acid for 15 s;

-Continuous jet of water for 20 s;

-Oil- and moisture-free jets of air;

-Application of Transbond XT Primer adhesive (3M, Monrovia, CA, USA) and photo-polymerized for 30 s;

-Application of Transbond XT at the base of the orthodontic accessory, which was polymerized for 20 s (10 s mesial and 10 s distal).