title: Curing mode affects bond strength of adhesively luted composite CAD/CAM restorations to dentin.
abstract: OBJECTIVE
  To determine the effect of curing mode and restoration-surface pre-treatment on the micro-tensile bond strength (μTBS) to dentin.
  
  
  METHODS
  Sandblasted CAD/CAM composite blocks (LAVA Ultimate, 3M ESPE) were cemented to bur-cut dentin using either the etch & rinse composite cement Nexus 3 ('NX3', Kerr) with Optibond XTR ('XTR', Kerr), or the self-etch composite cement RelyX Ultimate ('RXU', 3M ESPE) with Scotchbond Universal ('SBU', 3M ESPE). All experimental groups included different 'curing modes' (light-curing of adhesive and cement ('LL'), light-curing of adhesive and auto-cure of cement ('LA'), co-cure of adhesive through light-curing of cement ('AL'), or complete auto-cure ('AA')) and different 'restoration-surface pre-treatments' of the composite block (NX3: either a silane primer (Kerr), or the XTR adhesive; RXU: either silane primer (RelyX Ceramic Primer, 3M ESPE) and SBU, or solely SBU). After water-storage (7 days, 37°C), the μTBS was measured. Additionally, the degree of conversion (DC) of both cements was measured after 10min and after 1 week, either auto-cured (21°C/37°C) or light-cured (directly/through 3-mm CAD/CAM composite).
  
  
  RESULTS
  The linear mixed-effects model (α=0.05) revealed a significant influence of the factors 'curing mode' and 'composite cement', and a less significant effect of the factor 'restoration-surface pre-treatment'. Light-curing 'LL' revealed the highest μTBS, which decreased significantly for all other curing modes. For curing modes 'AA' and 'AL', the lowest μTBS and a high percentage of pre-testing failures were reported. Overall, DC increased with light-curing and incubation time.
  
  
  CONCLUSIONS
  The curing mode is decisive for the bonding effectiveness of adhesively luted composite CAD/CAM restorations to dentin.
authors.affiliation: KU Leuven - BIOMAT, Department of Oral Health Sciences, KU Leuven (University of Leuven) & Dentistry, University Hospitals Leuven, Belgium; Department of Conservative Dentistry, Periodontology and Preventive Dentistry, Hannover Medical School, Germany. Electronic address: Luehrs.Anne-Katrin@mh-hannover.de.
authors.forename: Anne-Katrin
authors.initials: AK
authors.lastname: Lührs
authors.affiliation: KU Leuven - BIOMAT, Department of Oral Health Sciences, KU Leuven (University of Leuven) & Dentistry, University Hospitals Leuven, Belgium.
authors.forename: Pong
authors.initials: P
authors.lastname: Pongprueksa
authors.affiliation: KU Leuven - BIOMAT, Department of Oral Health Sciences, KU Leuven (University of Leuven) & Dentistry, University Hospitals Leuven, Belgium.
authors.forename: Jan
authors.initials: J
authors.lastname: De Munck
authors.affiliation: Department of Conservative Dentistry, Periodontology and Preventive Dentistry, Hannover Medical School, Germany.
authors.forename: Werner
authors.initials: W
authors.lastname: Geurtsen
authors.affiliation: KU Leuven - BIOMAT, Department of Oral Health Sciences, KU Leuven (University of Leuven) & Dentistry, University Hospitals Leuven, Belgium.
authors.forename: Bart
authors.initials: B
authors.lastname: Van Meerbeek
mesh_terms: D000134:Acid Etching, Dental; D003188:Composite Resins / Q000737:chemistry*; D017076:Computer-Aided Design; D001840:Dental Bonding; D003738:Dental Cements / Q000737:chemistry*; D003799:Dental Stress Analysis / Q000379:methods*; D017220:Dentin-Bonding Agents / Q000737:chemistry; D006801:Humans; D066298:In Vitro Techniques; D008422:Materials Testing; D008963:Molar; D053758:Nanoparticles; D063065:Organophosphonates; D019279:Resin Cements; D012821:Silanes / Q000737:chemistry; D016369:Smear Layer; D013499:Surface Properties; D013696:Temperature; D013718:Tensile Strength
chemical_list: D003188:Composite Resins; D003738:Dental Cements; D017220:Dentin-Bonding Agents; C092987:Optibond; D063065:Organophosphonates; C483701:Rely X Unicem; D019279:Resin Cements; C454540:Scotchbond etchant; D012821:Silanes
keywords: CAD/CAM; Cement; Curing; Degree of conversion; Luting; Silane