title: Repair of dental resin-based composites.
abstract: OBJECTIVE
  The study analyzed the reparability and compatibility of light-curing resin-based composites (RBCs) of the categories "microhybrid," "nanohybrid," and "packable."
  
  
  METHODS
  Six RBCs with different matrix and filler formulation--purely methacrylate-based composites (MBCs), ormocer-based composites (OBCs), and silorane-based composites (SBCs)--were used for the specimens. Every material was combined with itself and with the other five RBCs, resulting in a total of 36 combination groups (n = 20). The specimens were polymerized, aged for 8 weeks in distilled water at 37 °C, and then repaired by means of a repair kit. Shear bond strength and fracture mode were measured after aging of the specimens, undergoing storage for 24 h in distilled water at 37 °C followed by thermocycling (5,000 cycles, 5-55 °C) and an additional 4-week storage in distilled water at 37 °C.
  
  
  RESULTS
  Data were statistically analyzed using ANOVA with TUKEY HSD post hoc test (α = 0.05). On average, the OBC Admira reached the highest value as a substrate material (30.41 MPa), and the SBC Filtek Silorane reached the lowest value (8.14 MPa). Filtek Silorane was identified as the repair material with the highest bond strength value (28.70 MPa), while a packable composite reached the lowest bond strength value (15.55 MPa). The analysis of the break modes showed that adhesive breaks are typical when strength is at its lowest (6.27 MPa). A large number of cohesive fractures are conspicuous when identical materials are used for repair, except Filtek Silorane (2 % cohesive fractures).
  
  
  CONCLUSIONS
  The study demonstrated that the effect of the different materials on bond strength varies strongly, depending on whether the material is used as filling or as repair material.
  
  
  CONCLUSIONS
  It is generally advisable but not compulsory to combine identical RBCs.
authors.affiliation: Department of Restorative Dentistry, Dental School, Ludwig-Maximilians-University, Goethestr. 70, 80336 Munich, Germany.
authors.forename: Veronika
authors.initials: V
authors.lastname: Baur
authors.forename: Nicoleta
authors.initials: N
authors.lastname: Ilie
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D003188:Composite Resins / Q000737:chemistry* / Q000145:classification; D001840:Dental Bonding; D003764:Dental Materials / Q000737:chemistry* / Q000145:classification; D058250:Dental Restoration Repair; D006801:Humans; D055115:Light-Curing of Dental Adhesives; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D053761:Nanocomposites / Q000737:chemistry; D063225:Organically Modified Ceramics / Q000737:chemistry; D010756:Phosphoric Acids / Q000737:chemistry; D058105:Polymerization; D019279:Resin Cements / Q000737:chemistry; D033081:Shear Strength; D012821:Silanes / Q000737:chemistry; D062047:Silorane Resins / Q000737:chemistry; D012833:Siloxanes / Q000737:chemistry; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: C520091:CeramX; C438313:Clearfil SE Bond; C480092:Clearfil repair; D003188:Composite Resins; D003764:Dental Materials; C466112:Esthet-X; C474035:Filtek Supreme; D008689:Methacrylates; D063225:Organically Modified Ceramics; D010756:Phosphoric Acids; D019279:Resin Cements; D012821:Silanes; D062047:Silorane Resins; D012833:Siloxanes; C121818:Tetric ceram; C479084:admira; C555513:silorane composite resin; D014867:Water; C017492:methacryloxypropyltrimethoxysilane; C030242:phosphoric acid