title: The effect of filler addition on biaxial flexure strength and modulus of commercial dentin bonding systems.
abstract: OBJECTIVE
  To evaluate the effects of filler addition on the biaxial flexural strength and modulus of two commercial adhesive systems.
  
  
  METHODS
  The systems were either unfilled (Adper Single Bond [3M ESPE] and Prime and Bond 2.1 [Dentsply]) or filled (Adper Single Bond Plus [3M ESPE] and Prime and Bond NT [Dentsply]). Resin disks of each product (0.6 mm thick and 6.2 mm in diameter) were prepared in Teflon molds (n = 11 each group; 44 in total). The adhesive solutions were light activated with a halogen light-curing unit. The disks were stored dry in the dark 24 hours before biaxial flexural testing in a universal testing machine until fracture (1.27 mm/minute; model 5844, Instron). Data were statistically analyzed by one-way ANOVA and Tukey post hoc test at a preset alpha of 0.05.
  
  
  RESULTS
  Flexural strength values (MPa) (SD) were Single Bond 62 (16); Single Bond Plus 46 (15); Prime and Bond 59 (13); and Prime and Bond NT 85 (16). The flexural moduli (MPa) (SD) were Single Bond 1,026 (241); Single Bond Plus 1,180 (188); Prime and Bond 744 (146); and Prime and Bond NT 1,539 (267). Based on the results, Prime and Bond NT (filled) exhibited higher flexural strength and modulus than Prime and Bond (unfilled), while no significant difference in both parameters was noted between Single Bond and Single Bond Plus.
  
  
  CONCLUSIONS
  Filler addition to bonding agents can increase the flexural strength and modulus; however, results are product dependent.
authors.affiliation: Operative Dentistry Division, Department of Restorative Dentistry, Piracicaba Dental School, State University of Campinas, Piracicaba, São Paulo, Brazil. giannini@fop.unicamp
authors.forename: Marcelo
authors.initials: M
authors.lastname: Giannini
authors.forename: Donald
authors.initials: D
authors.lastname: Mettenburg
authors.forename: César Augusto Galvão
authors.initials: CA
authors.lastname: Arrais
authors.forename: Frederick Allen
authors.initials: FA
authors.lastname: Rueggeberg
mesh_terms: D003799:Dental Stress Analysis; D017220:Dentin-Bonding Agents / Q000737:chemistry; D055119:Elastic Modulus; D055115:Light-Curing of Dental Adhesives; D008422:Materials Testing; D010316:Particle Size; D018583:Pliability; D019279:Resin Cements / Q000737:chemistry
chemical_list: D017220:Dentin-Bonding Agents; D019279:Resin Cements