title: Adhesive analysis of voids in Class II composite resin restorations at the axial and gingival cavity walls restored under in vivo versus in vitro conditions.
abstract: OBJECTIVE
  Adhesive analysis, under the scanning electron microscope of microtensile specimens that failed through the adhesive interface, was conducted to evaluate the amount of voids present at the axial versus gingival cavity walls of class II composite restorations restored under in vivo and in vitro conditions.
  
  
  METHODS
  Five patients received class II resin composite restorations, under in vivo and in vitro conditions. A total of 14 premolar teeth yielded 59 (n=59) microtensile adhesive specimens that fractured through the adhesive interface. The fractured surfaces of all specimens were examined and the % area of voids was measured.
  
  
  RESULTS
  Voids at the adhesive joint were highly predictive of bond strengths. An increase in the number of voids resulted in a decrease in the microtensile bond strength. The area of voids at the adhesive interface was as follows: in vivo axial 13.6+/-25.6% (n=12); in vivo gingival 48.8+/-29.2% (n=12); in vitro axial 0.0+/-0.0% (n=19) and in vitro gingival 11.7+/-17.6% (n=16).
  
  
  CONCLUSIONS
  Composite resin may bond differently to dentin depending upon the amount of voids and the cavity wall involved. The bond to the gingival wall was not as reliable as the bond to the axial wall. An increase in the amount of surface voids was a major factor for reducing microtensile bond strengths of adhesive to dentin.
authors.affiliation: Department of Restorative Dentistry, University of Missouri-Kansas City, School of Dentistry, 650 East 25th Street, Kansas City, MO 64108, USA. purkj@umkc.edu
authors.forename: John H
authors.initials: JH
authors.lastname: Purk
authors.forename: Vladimir
authors.initials: V
authors.lastname: Dusevich
authors.forename: Alan
authors.initials: A
authors.lastname: Glaros
authors.forename: J David
authors.initials: JD
authors.lastname: Eick
mesh_terms: D003188:Composite Resins; D001840:Dental Bonding; D003737:Dental Cavity Preparation; D018772:Dental Marginal Adaptation; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D003804:Dentin; D006801:Humans; D016062:Porosity; D012044:Regression Analysis; D013499:Surface Properties; D013718:Tensile Strength; D014867:Water
chemical_list: D003188:Composite Resins; D014867:Water