title: Resin-dentin Bond Stability of Experimental 4-META-based Etch-and-rinse Adhesives Solvated by Ethanol or Acetone.
abstract: OBJECTIVE
  To investigate the influence of 4-META concentration and type of solvent on the degree of conversion (DC%) and resin-dentin bond stability of experimental etch-and-rinse adhesives.
  
  
  METHODS
  Four different concentrations of 4-META (12 wt%, 20 wt%, 30 wt%, 40 wt%) were added to a model adhesive system consisting of TEG-DMA (25 wt%), UDMA (20 wt%), HEMA (30 wt%), water (4 wt%), camphorquinone (0.5 wt%), and tertiary amine (0.5 wt%) dissolved in 20% acetone (A12, A20, A30 and A40) or 20% ethanol (E12, E20, E30 and E40). DC% was evaluated by FT-IR spectroscopy. Human molars were wet ground until the occlusal dentin was exposed, the adhesive systems were applied after 37% phosphoric acid etching, and resin composite buildups were incrementally constructed. After storage in distilled water at 37°C for 24 h, the teeth were cut into resin-dentin beams (cross-sectional area 1 mm2). Microtensile bond strength (μTBS) was evaluated after 24 h, 6 months, and 1 year of water storage at 37°C. The failure mode was categorized as adhesive, mixed, or cohesive. Data were analyzed using ANOVA and Tukey's HSD test (α = 0.05).
  
  
  RESULTS
  A12 presented the lowest DC% (p < 0.05). All the other adhesive systems showed statistically similar DC% (p > 0.05). All adhesive systems maintained resin-dentin bond stability after 6 months of water storage, while only A40 and E40 maintained it after 1 year.
  
  
  CONCLUSIONS
  Irrespective of the type of organic solvent, the incorporation of high concentrations of 4-META (40 wt%) improved the resin-dentin bond stability of the experimental etch-and-rinse adhesive systems over a period of 1 year.
authors.forename: Cristiane Mariote
authors.initials: CM
authors.lastname: Amaral
authors.forename: Alice Marques
authors.initials: AM
authors.lastname: Diniz
authors.forename: Eugênio Braz Rodrigues
authors.initials: EB
authors.lastname: Arantes
authors.forename: Glauco Botelho
authors.initials: GB
authors.lastname: Dos Santos
authors.forename: Jaime Dutra
authors.initials: JD
authors.lastname: Noronha-Filho
authors.forename: Eduardo Moreira
authors.initials: EM
authors.lastname: da Silva
mesh_terms: D000096:Acetone / Q000494:pharmacology*; D000134:Acid Etching, Dental / Q000379:methods*; D001840:Dental Bonding; D017220:Dentin-Bonding Agents; D000431:Ethanol / Q000494:pharmacology*; D006801:Humans; D008422:Materials Testing; D008689:Methacrylates; D012117:Resins, Synthetic; D012997:Solvents / Q000494:pharmacology*
chemical_list: D017220:Dentin-Bonding Agents; D008689:Methacrylates; D012117:Resins, Synthetic; D012997:Solvents; D000096:Acetone; D000431:Ethanol; C034139:4-methacryloxyethyltrimellitic acid anhydride