Effect of surface treatment and aging on bond strength of composite resin onlays.
BACKGROUND
Additional polymerization of indirect composite resins enhances their physical properties but lessens the potential for chemical bonding.


OBJECTIVE
The purpose of this in vitro study was to evaluate the influence of different surface treatments and 6-month water storage on the microtensile bond strength (μTBS) of composite resin onlays.


METHODS
Composite resin onlays (Filtek Z250) randomly received 6 different surface treatments: (1) airborne-particle abrasion with 27-μm alumina particles+Adper Scotchbond 1XT adhesive application, (2) airborne-particle abrasion with alumina particles+silane application (ESPE SIL)+Adper Scotchbond 1XT, (3) airborne-particle abrasion with alumina particles+Scotchbond Universal adhesive, (4) tribochemical silica coating with 30-μm particles (CoJet Sand)+Adper Scotchbond 1XT adhesive, (5) tribochemical silica coating+silane application+Adper Scotchbond 1XT, and (6) tribochemical silica coating+Scotchbond Universal adhesive. Onlays were luted to fresh composite resin specimens with RelyX Ultimate resin cement. Bonded assemblies were stored in water for 24 hours or 6 months at 37°C and subjected to the μTBS test. Additional surface-treated composite resin onlays were analyzed with a contact profilometer to determine average roughness, and micromorphologic changes were analyzed with scanning electron microscopy.


RESULTS
Airborne-particle abrasion with alumina followed by Adper Scotchbond 1XT or Scotchbond Universal adhesive application provided the highest bond strength values at 24 hours. Lower values were obtained after tribochemical silica coating. After 6 months of artificial aging, airborne-particle abrasion with alumina or silica-coated alumina particles followed by Scotchbond Universal application yielded the greatest bond strength results. Airborne-particle abrasion with alumina produced the highest roughness values and a more irregular surface.


CONCLUSIONS
Adhesive selection seems to be relevant to the μTBS of luted composite resin onlays after 6 months of water aging, as specimens treated with Scotchbond Universal, after alumina airborne-particle abrasion or tribochemical silica coating, yielded the highest values and better aging stability.
Fellow Researcher, Department of Stomatology, Health Sciences Faculty, Rey Juan Carlos University, Madrid, Spain.
Maria
M
Cura
Doctoral student, Department of Stomatology, Health Sciences Faculty, Rey Juan Carlos University, Madrid, Spain.
Inmaculada
I
González-González
Assistant Professor, Department of Stomatology, Health Sciences Faculty, Rey Juan Carlos University, Madrid, Spain.
Victoria
V
Fuentes
Associate Professor, Department of Stomatology, Health Sciences Faculty, Rey Juan Carlos University, Madrid, Spain. Electronic address: laura.ceballos@urjc.es.
Laura
L
Ceballos
D020906:Air Abrasion, Dental / Q000379:methods / Q000592:standards; D000537:Aluminum Oxide / Q000627:therapeutic use; D003188:Composite Resins / Q000627:therapeutic use*; D001840:Dental Bonding / Q000379:methods* / Q000592:standards; D003799:Dental Stress Analysis; D006801:Humans; D066298:In Vitro Techniques; D007284:Inlays / Q000379:methods* / Q000592:standards; D019279:Resin Cements / Q000627:therapeutic use; D013499:Surface Properties; D013997:Time Factors
D003188:Composite Resins; D019279:Resin Cements; C041330:Scotchbond; D000537:Aluminum Oxide