title: Bond strengths of repaired laboratory composites using three surface treatments and three primers.
abstract: OBJECTIVE
  To determine the in vitro bond strength of three laboratory composites repaired with their corresponding direct repair composites using various combinations of surface treatments and primers.
  
  
  METHODS
  The effects of three surface treatments (600-grit as a control, air abrasion with 50-microm Al2O3 particles and 8% hydrofluoric acid etching) and three primers with different formulations [Artglass Liquid (resin/silane), Sculpture Thinning Liquid (resin), and Targis Wetting Agent (silane)] were studied on three laboratory composites (Artglass, Targis and Sculpture). Specimens were stored for 24 hours at 37 degrees C and 100% relative humidity. Tensile bond strengths were determined on an Instron universal testing machine at a crosshead speed of 0.5 mm/minute at room temperature, keeping the specimens moist throughout the testing procedure.
  
  
  RESULTS
  Three-way analysis of variance (SuperANOVA) indicated that in general, 8% hydrofluoric acid produced the highest bond strengths when used to prepare the three laboratory composites. Either 8% hydrofluoric acid or air abrasion with Al2O3 particles produced the strongest repair bond strengths for Tetric Ceram when used with the resin/silane primer (Artglass Liquid) with values ranging from 36.9 to 39.6 MPa., respectively, as did the combination of hydrofluoric acid and the silane primer (Targis Wetting Agent) 38.2 MPa. The 8% hydrofluoric acid produced the highest bond strengths when used to prepare Artglass and Sculpture and used with the resin/silane primer, 32.9 and 38.7 MPa, respectively. Most bond failures (65%) were adhesive between the laboratory and repair composites, followed by cohesive failures in the laboratory composite with Artglass/Charisma and Targis/Tetric Ceram; and cohesive in the repair composite with Sculpture/Sculpt-It. Overall, the resin/silane primer produced the highest repair bond strengths for Al2O3- and hydrofluoric acid-treated composites.
  
  
  CONCLUSIONS
  Air abrasion and hydrofluoric acid etching offer acceptable bond strengths for laboratory composites repaired with direct repair composites. Repair bond strengths are enhanced by the application of a resin/silane primer.
authors.affiliation: Department of Restorative Dentistry and Biomaterials, University of Texas Dental Branch at Houston, 6516 M.D. Anderson Blvd., Room 493, Houston, TX 77030-3402, USA. Cynthia.Trajtenberg@uth.tmc.edu
authors.forename: Cynthia P
authors.initials: CP
authors.lastname: Trajtenberg
authors.forename: John M
authors.initials: JM
authors.lastname: Powers
mesh_terms: D000269:Adhesives; D020906:Air Abrasion, Dental; D000537:Aluminum Oxide; D000704:Analysis of Variance; D003188:Composite Resins; D001840:Dental Bonding; D003799:Dental Stress Analysis; D005899:Glass Ionomer Cements; D006858:Hydrofluoric Acid; D008422:Materials Testing; D019279:Resin Cements; D012613:Sculpture; D012821:Silanes; D012823:Silicate Cement; D013499:Surface Properties; D013718:Tensile Strength
chemical_list: D000269:Adhesives; D003188:Composite Resins; D005899:Glass Ionomer Cements; D019279:Resin Cements; D012821:Silanes; C111282:dental polyglass; D012823:Silicate Cement; D000537:Aluminum Oxide; D006858:Hydrofluoric Acid