title: The addition of nanostructured hydroxyapatite to an experimental adhesive resin.
abstract: OBJECTIVE
  Was produced nanostructured hydroxyapatite (HAnano) and evaluated the influence of its incorporation in an adhesive resin.
  
  
  METHODS
  HAnano was produced by a flame-based process and was characterized by scanning electron microscopy. The surface area, particle size, micro-Raman and cytotoxicity were evaluated. The organic phase was formulated by mixing 50 wt.% Bis-GMA, 25 wt.% TEGDMA, and 25 wt.% HEMA. HAnano was added at seven different concentrations: 0; 0.5; 1; 2; 5; 10 and 20 wt.%. Adhesive resins with hydroxyapatite incorporation were evaluated for their radiopacity, degree of conversion, flexural strength, softening in solvent and microshear bond strength. The data were analyzed by one-way ANOVA and Tukey's post hoc test (α=0.05), except for softening in solvent (paired t-test) and cytotoxicity (two-way ANOVA and Bonferroni).
  
  
  RESULTS
  HAnano presented 15.096 m(2)/g of specific surface area and a mean size of 26.7 nm. The radiopacity values were not different from those of 1-mm aluminium. The degree of conversion ranged from 52.2 to 63.8%. The incorporation of HAnano did not influence the flexural strength, which ranged from 123.3 to 143.4MPa. The percentage of reduction of the microhardness after immersion in the solvent became lower as the HAnano concentration increased. The addition of 2% nanostructured hydroxyapatite resulted in a higher value of microshear bond strength than the control group (p<0.05).
  
  
  CONCLUSIONS
  The incorporation of 2% of nanostructured hydroxyapatite into an adhesive resin presented the best results.
  
  
  CONCLUSIONS
  The incorporation of nanostructured hydroxyapatite increases the adhesive properties and may be a promising filler for adhesive resin.
authors: Dental Materials Laboratory, School of Dentistry, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil. vicente.leitune@ufrgs.br
authors: Vicente Castelo Branco
authors: VC
authors: Leitune
authors: Fabrício Mezzomo
authors: FM
authors: Collares
authors: Rafael Mello
authors: RM
authors: Trommer
authors: Daniela Guerra
authors: DG
authors: Andrioli
authors: Carlos Pérez
authors: CP
authors: Bergmann
authors: Susana Maria Werner
authors: SM
authors: Samuel
mesh_terms: D016475:3T3 Cells / Q000187:drug effects; D000704:Analysis of Variance; D000818:Animals; D017438:Bisphenol A-Glycidyl Methacrylate; D001840:Dental Bonding; D003799:Dental Stress Analysis; D017220:Dentin-Bonding Agents / Q000737:chemistry* / Q000633:toxicity; D017886:Durapatite; D006244:Hardness; D055115:Light-Curing of Dental Adhesives; D008422:Materials Testing; D008689:Methacrylates; D051379:Mice; D049329:Nanostructures; D058567:Photoinitiators, Dental; D018583:Pliability; D011092:Polyethylene Glycols; D058105:Polymerization; D011109:Polymethacrylic Acids; D011859:Radiography; D019279:Resin Cements / Q000737:chemistry* / Q000633:toxicity; D033081:Shear Strength; D012995:Solubility; D018709:Statistics, Nonparametric; D013499:Surface Properties; D013729:Terpenes; D062366:para-Aminobenzoates
chemical_list: D017220:Dentin-Bonding Agents; D008689:Methacrylates; D058567:Photoinitiators, Dental; D011109:Polymethacrylic Acids; D019279:Resin Cements; D013729:Terpenes; D062366:para-Aminobenzoates; C020946:triethylene glycol dimethacrylate; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate; C048339:camphoroquinone; C005044:hydroxyethyl methacrylate; C030747:ethyl 4-dimethylaminobenzoate; D017886:Durapatite