title: Internal adaptation of resin composites at two configurations: Influence of polymerization shrinkage and stress.
abstract: This study compared internal adaptation of composites under different C-factors and examined the relationship between internal adaptation and polymerization shrinkage parameters.
  
  
  
  Cylindrical cavities 3mm in diameter were prepared in 100 human third molars in two depths: 4mm high C-factor (H-CF) or 1mm low C-factor (L-CF). After adhesive application (Clearfil SE One, Kuraray Noritake), the composite was placed in two increments in three subgroups: Filtek Supreme (FS, 3M ESPE); Charisma Diamond (CD, Heraeus Kulzer); Amelogen Plus (AP, Ultradent); and as a single increment in two subgroups: Tetric EvoCeram Bulk Fill (TB, Ivoclar Vivadent) and Venus Bulk Fill (VB, Heraeus Kulzer). After thermo-mechanical load-cycles, imperfect margin percentage (%IM) was calculated using swept-source optical coherence tomography (SS-OCT) imaging. The relationships between %IM and linear shrinkage (LS) and shrinkage stress, measured under either zero-compliance (PS0) or compliance-allowed (PS) conditions were evaluated.
  
  
  
  The %IM was significantly different between H-CF and L-CF groups. The %IM in H-CF turned out to be as groups CD, FS≤TB<AP, VB. The %IM in L-CF showed as groups CD, TB≤FS, AP<VB. There were significant correlations between shrinkage parameters and %IM, except between PS0 and %IM in L-CF.
  
  
  
  Internal adaptation in a high C-factor cavity was inferior to that in a low C-factor cavity for both conventional and bulk-filled composites. Internal adaptation, polymerization shrinkage, and stress were different among composite materials. Polymerization stress under the compliance-allowed condition showed significant correlations with internal adaptations in high and low C-factor cavities.
authors.affiliation: Department of Conservative Dentistry, St.Vincent hospital, Catholic University of Korea #93 Jungbu-daero, Paldal-gu, Suwon, , Gyeonggi-do, Republic of Korea. Electronic address: han7537@hotmail.com.
authors.forename: Seung-Hoon
authors.initials: SH
authors.lastname: Han
authors.affiliation: Biomimetics Biomaterials Biophotonics & Technology Laboratory, Department of Restorative Dentistry, School of Dentistry, University of Washington 1959 NE Pacific St., Box 357456 Seattle, WA, USA. Electronic address: arsadr@uw.edu.
authors.forename: Alireza
authors.initials: A
authors.lastname: Sadr
authors.affiliation: Cariology and Operative Dentistry Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Global COE, International Research Center for Molecular Science in Tooth and Bone Diseases, Tokyo Medical and Dental University, 1-5-45 Yushima Bunkyo-ku, Tokyo, Japan. Electronic address: Tagami.ope@tmd.ac.jp.
authors.forename: Junji
authors.initials: J
authors.lastname: Tagami
authors.affiliation: Department of Conservative Dentistry, Oral Science Research Center, College of Dentistry, Yonsei University #50 Yonsei-ro, Seodaemun-gu, Seoul, Republic of Korea. Electronic address: sunghopark@yuhs.ac.
authors.forename: Sung-Ho
authors.initials: SH
authors.lastname: Park
mesh_terms: D003188:Composite Resins; D006801:Humans; D008422:Materials Testing; D058105:Polymerization
chemical_list: D003188:Composite Resins
keywords: C-factor; Compliance; Composite resin; Correlation; Internal adaptation; Optical coherence tomography; Polymerization shrinkage; Polymerization stress; SS-OCT