title: Microhardness of composite materials with different organic phases in deep class II cavities: an in vitro study.
abstract: OBJECTIVE
  This study compared the microhardness of three composite resins with different organic matrices in deep class II cavities.
  
  
  METHODS
  A total of 36 extracted molars were randomly assigned to six groups and standardized class II cavities were prepared. The cavity design comprised three steps in a mesiodistal direction with an increasing depth (2, 4, and 6 mm). Twelve cavities each were restored using Filtek Supreme (FS), Quixfil (QF), and Filtek Silorane (SI). The materials were applied in incremental layers of 2 mm and cured either with Halogen Translux Energy (HTE) (n=18) or LED Bluephase C8 (LED) (n=18). Subsequently, the specimens were cross-sectioned, and microhardness was determined in various depths and at two different distances from the matrix.
  
  
  RESULTS
  QF yielded the highest KHN microhardness values (92.67 ± 12.77), followed by FS (65.53 ± 19.52) and SI (57.67 ± 8.33). Composites cured with LED achieved higher KHN values. All materials showed the highest microhardness values within the superficial increments and at a distance of 1000 μm from the matrix.
authors.affiliation: Department of Operative Dentistry and Peridontology, Dental School and Hospital Freiburg, Freiburg, Germany. joerg.tchorz@uniklinik-freiburg.de
authors.forename: J P
authors.initials: JP
authors.lastname: Tchorz
authors.forename: R
authors.initials: R
authors.lastname: Doll
authors.forename: M
authors.initials: M
authors.lastname: Wolkewitz
authors.forename: E
authors.initials: E
authors.lastname: Hellwig
authors.forename: C
authors.initials: C
authors.lastname: Hannig
mesh_terms: D003188:Composite Resins / Q000737:chemistry*; D055117:Curing Lights, Dental / Q000145:classification; D003737:Dental Cavity Preparation / Q000145:classification*; D003764:Dental Materials / Q000737:chemistry*; D006244:Hardness; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D058105:Polymerization; D011829:Radiation Dosage; D062047:Silorane Resins; D012833:Siloxanes / Q000737:chemistry; D013499:Surface Properties; D013696:Temperature
chemical_list: D003188:Composite Resins; D003764:Dental Materials; C474035:Filtek Supreme; C510379:QuiXfil; D062047:Silorane Resins; D012833:Siloxanes; C555513:silorane composite resin