title: Evaluation of crack propagation in dental composites by optical coherence tomography.
abstract: OBJECTIVE
  The purpose of this study was to image the sites of fracture initiation and slow crack propagation in a fiber reinforced composite, using the optical coherence tomography (OCT) technique.
  
  
  METHODS
  Bar specimens (2mm x 3mm x 25mm) of fiber reinforced composite were mechanically and thermally cycled to emulate oral conditions. The interior of these samples was analyzed prior to and after loading, using OCT. The device used was a home-built Fourier domain OCT setup working at 800 nm with 6 microm spatial resolution.
  
  
  RESULTS
  Intact specimens after load cycling were analyzed. It was clearly seen that OCT images provide an insight into crack propagation, which is not seen by the naked eye.
  
  
  CONCLUSIONS
  By using OCT the possibility of analyzing the fracture propagation quantitatively, and in depth, was added, opening up possibilities to quantitative studies.
authors.affiliation: Graduate Program in Odontology, Universidade Federal de Pernambuco, Recife, PE, Brazil. anakarla_81@hotmail.com
authors.forename: Ana K S
authors.initials: AK
authors.lastname: Braz
authors.forename: Bernardo B C
authors.initials: BB
authors.lastname: Kyotoku
authors.forename: Rodivan
authors.initials: R
authors.lastname: Braz
authors.forename: Anderson S L
authors.initials: AS
authors.lastname: Gomes
mesh_terms: D002516:Ceramics / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry*; D005583:Fourier Analysis; D005898:Glass / Q000737:chemistry; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008422:Materials Testing; D011108:Polymers / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D041623:Tomography, Optical Coherence / Q000379:methods*
chemical_list: D003188:Composite Resins; D003764:Dental Materials; C039578:Kevlar Aramid fibers; D011108:Polymers; C485361:Suprafil; C009753:fiberglass; C023506:Glass ceramics