title: Interfacial Adaptation of Composite Restorations Before and After Light Curing: Effects of Adhesive and Filling Technique.
abstract: OBJECTIVE
  To investigate the effects of placement technique and adhesive material on adaptation of composites before and after light curing.
  
  
  METHODS
  Cylindrical cavities (3 mm diameter, 1.7 mm depth) in extracted human molars were restored in 6 groups (n=5) using 2 adhesives--two-step self-etching Clearfil SE Bond 2 (SE2) and all-in-one Clearfil Tri-S Bond Plus (TSP) (Kuraray Noritake Dental)--and 2 composites--Estelite Sigma Quick (ESQ) and Estelite Flow Quick (FLQ) (Tokuyama Dental)--placed with three different techniques: ESQ bulk placed, FLQ lining followed by ESQ and FLQ bulk placed. Specimens were scanned twice using swept-source optical coherence tomography (SS-OCT) before and after photopolymerization of the composite. Gap formation during polymerization or the difference in floor interface (DFI%) and final unsealed interface (USI%) were measured by image coregistration and subtraction on 6 diametrical planes across each scan.
  
  
  RESULTS
  Two-way ANOVA suggested that both factors (adhesive and filling technique) and their interaction were significant (p<0.001). SE2 showed significantly lower DFI% than did TSP when the composites were placed in bulk, but no difference was found when flowable lining was applied (p<0.05). Within TSP, all filling techniques were significantly different and the lining group showed the lowest values, followed by ESQ-bulk. Overall, SE2 always showed lower UFI% than did TSP, while there was no difference among different techniques within SE2.
  
  
  CONCLUSIONS
  SS-OCT is a unique method to observe the pre-existing interfacial defects and gaps developed during polymerization, which were found to depend on both placement technique and applied adhesive.
authors.forename: Nariaki
authors.initials: N
authors.lastname: Yoshimine
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Shimada
authors.forename: Junji
authors.initials: J
authors.lastname: Tagami
authors.forename: Alireza
authors.initials: A
authors.lastname: Sadr
mesh_terms: D003188:Composite Resins / Q000737:chemistry*; D055117:Curing Lights, Dental / Q000145:classification; D003737:Dental Cavity Preparation / Q000379:methods; D018772:Dental Marginal Adaptation; D003764:Dental Materials / Q000737:chemistry*; D003793:Dental Restoration, Permanent / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D055115:Light-Curing of Dental Adhesives / Q000379:methods*; D008422:Materials Testing; D058105:Polymerization; D019279:Resin Cements / Q000737:chemistry; D013382:Subtraction Technique; D013499:Surface Properties; D041623:Tomography, Optical Coherence / Q000379:methods
chemical_list: C438313:Clearfil SE Bond; C515604:Clearfil Tri-S Bond; D003188:Composite Resins; D003764:Dental Materials; C507124:Estelite sigma; D019279:Resin Cements; C527485:estelite flow quick