title: Effect of filler content on the microtensile bond strength of composite resin and dentin in Class I cavities.
abstract: OBJECTIVE
  To investigate the effect of filler content on microtensile bond strength (Μ-TBS) in Class I cavities.
  
  
  METHODS
  Experimental composites with filler contents of 80%, 76%, 70%, 60%, and 50% by weight were used. Polymerization shrinkage was measured with Acuvol, and a three-point flexural test was performed to determine flexural properties. For evaluation of Μ-TBS, 25 extracted human molars were randomly divided into five groups and Class I cavities were prepared. After filling with one of the experimental composites and curing for 40 seconds, teeth were serially sectioned perpendicular to the cavity floor. Stick-shaped samples were tested with a microtensile tester. Statistical analysis was conducted using ANOVA and Pearson correlation tests.
  
  
  RESULTS
  Significant correlations were found between filler content and polymerization shrinkage (r = -0.973, P < .05) and the filler content and Young modulus (r = 0.891, P < .05). Different filler contents in the experimental composites had no significant effect on Μ-TBS or flexural strength.
  
  
  CONCLUSIONS
  In a Class I cavity model, this in vitro study showed that the filler content did not influence the flexural strength of experimental composite resins and had no effect on the microtensile bond strength between composite resin and dentin.
authors.affiliation: Department of Cariology and Endodontology, Peking University School and Hospital of Stomatology, Beijing, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Han
authors.forename: Yanmei
authors.initials: Y
authors.lastname: Dong
authors.forename: Xuejun
authors.initials: X
authors.lastname: Gao
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Wang
authors.forename: Fucong
authors.initials: F
authors.lastname: Tian
mesh_terms: D000465:Algorithms; D000535:Aluminum; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding; D003737:Dental Cavity Preparation / Q000145:classification*; D003764:Dental Materials / Q000737:chemistry*; D003804:Dentin / Q000648:ultrastructure*; D055119:Elastic Modulus; D006801:Humans; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D018583:Pliability; D011092:Polyethylene Glycols / Q000737:chemistry; D058105:Polymerization; D011109:Polymethacrylic Acids / Q000737:chemistry; D011140:Polyurethanes / Q000737:chemistry; D012821:Silanes / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013718:Tensile Strength; D013997:Time Factors
chemical_list: D003188:Composite Resins; D003764:Dental Materials; D008689:Methacrylates; D011109:Polymethacrylic Acids; D011140:Polyurethanes; D012821:Silanes; C029824:urethane dimethacrylate luting resin; C020946:triethylene glycol dimethacrylate; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate; D012822:Silicon Dioxide; D000535:Aluminum