Table 1.

Orthodontic adhesives included in the study.

Orthodontic Adhesive	Manufacturer	Components
Opal Seal	Opal Orthodontics, South Jordan, UT, USA	HPMA, Bis-GMA; glass ceramic and nanofillers, fluoride
Light Bond	Reliance Ortho Prod. Inc., Itasca, Il, USA	UDMA, TEGDMA; 85% fused silica, fluoride
Blugloo	Ormco Corporation, Glendora, CA, USA	Uncured methacrylate monomer; inert material fillers, fused silica, fluoride
Experimental material C1	“Raluca Ripan” Institue for Research in Chemistry, Cluj-Napoca, Romania	Bis-GMA, TEGDMA, UDMA; 80% Silanized strontium and zirconium fluoro-silicate glass, colloidal silica, quartz

HPMA: N-(2-Hydroxypropyl) methacrylamide (Sigma-Aldrich, Saint Louis, MO, USA); BIS-GMA: bisphenol A-glycidyl methacrylate (Sigma-Aldrich, Saint Louis, MO, USA); UDMA: urethane dimetacrylate (Sigma-Aldrich, Saint Louis, MO, USA).