title: Effect of evaporation on the shelf life of a universal adhesive.
abstract: OBJECTIVE
  The purpose of this study was to evaluate how evaporation affects the shelf life of a one-bottle universal adhesive.
  
  
  METHODS
  Three different versions of Scotchbond Universal (SBU, 3M ESPE, Seefeld, Germany) were prepared using a weight-loss technique. SBU0 was left open to the air until maximal weight loss was obtained, whereas SBU50 was left open until 50% of evaporation occurred. In contrast, SBU100 was kept closed and was assumed to contain the maximum concentration of all ingredients. The degree of conversion (DC) was determined by using Fourier transform infrared spectroscopy on different substrates (on dentin or glass plate and mixed with dentin powder); ultimate microtensile strength and microtensile bond strength to dentin were measured as well.
  
  
  RESULTS
  DC of the 100% solvent-containing adhesive (SBU100) was higher than that of the 50% (SBU50) and 0% (SBU0) solvent-containing adhesives for all substrates. DC of the adhesive applied onto glass and dehydrated dentin was higher than that applied onto dentin. Even though the ultimate microtensile strength of SBU0 was much higher than that of SBU50 and SBU100, its bond strength to dentin was significantly lower.
  
  
  CONCLUSIONS
  Evaporation of adhesive ingredients may jeopardize the shelf life of a one-bottle universal system by reducing the degree of conversion and impairing bond strength. However, negative effects only became evident after more than 50% evaporation.
authors: P
authors: P
authors: Pongprueksa
authors: V
authors: V
authors: Miletic
authors: J
authors: J
authors: De Munck
authors: N R
authors: NR
authors: Brooks
authors: F
authors: F
authors: Meersman
authors: E
authors: E
authors: Nies
authors: B
authors: B
authors: Van Meerbeek
authors: K L
authors: KL
authors: Van Landuyt
mesh_terms: D000269:Adhesives; D013718:Tensile Strength
chemical_list: D000269:Adhesives