title: Evaluation of the physical properties of dental resin composites using optical fiber sensing technology.
abstract: The characterization of the physical properties of dental resin composites is fraught with difficulties relating to significant intra and inter test parameter variabilities and is relatively time consuming and expensive. The main aim of this study was to evaluate whether optical fiber Bragg grating (FBG) sensing system may become a viable tool to study dental material characteristics. Of particular focus was the potential for the system to demonstrate a multi parameter all-in-one feature.
  
  
  
  A miniature FBG was embedded in six different dental resin composites and employed as a sensor to evaluate linear polymerization shrinkage, thermal expansion and water sorption. Six commercially available dental composites with different filler types and volume are evaluated. The tests are repeated with three sets of samples. The curing characteristics and residual strain gradient exhibited by the cured dental composites were also observed and commented.
  
  
  
  Among the studied samples, SDR shows lowest polymerization shrinkage, while Beautifil FO3 shows the highest. The results also show clear distinction between particle filler type and fiber reinforcement based composites in their polymerization shrinkage properties. The agreement of the results with existing literatures show that FBG based system provides accurate results. Polymerization shrinkage rate of the samples are also obtained. Thermal expansion of the composites are measured using the FBG sensing method for the first time and is correlated with resin type, volume, filler type and glass transition temperature. The water sorption characteristics of the dental composite are also successfully measured using the FBG sensing method. The high level of repeatability and the low standard deviations shown in the results indicate good reliability with the use of FBG sensors.
  
  
  
  This study demonstrates how optical fiber technology can provide simple and reliable methods of measuring the critical physical properties of dental composites. In addition due to the embedding and preservation of the sensor within the samples multiple parameters can be tested for with the same sample. These features are expected to greatly assist material science researchers in dentistry as well as other biomedical fields. Of some interest the phenomenon of stress relaxation of dental composite at higher temperature was observed.
authors.affiliation: School of Electrical, Computer and Telecommunications Engineering, University of Wollongong, Wollongong, Australia; School of Mechanical and Manufacturing Engineering, UNSW Australia. Electronic address: ginu@uow.edu.au.
authors.forename: Ginu
authors.initials: G
authors.lastname: Rajan
authors.affiliation: Faculty of Dentistry, University of Sydney, Australia.
authors.forename: Paul
authors.initials: P
authors.lastname: Shouha
authors.affiliation: Faculty of Dentistry, University of Sydney, Australia.
authors.forename: Ayman
authors.initials: A
authors.lastname: Ellakwa
authors.affiliation: School of Electrical Engineering and Telecommunications, UNSW Australia.
authors.forename: Kishore
authors.initials: K
authors.lastname: Bhowmik
authors.affiliation: School of Electrical, Computer and Telecommunications Engineering, University of Wollongong, Wollongong, Australia.
authors.forename: Jiangtao
authors.initials: J
authors.lastname: Xi
authors.affiliation: School of Mechanical and Manufacturing Engineering, UNSW Australia.
authors.forename: Gangadhara
authors.initials: G
authors.lastname: Prusty
mesh_terms: D003188:Composite Resins; D003764:Dental Materials; D005898:Glass; D008422:Materials Testing; D055100:Optical Fibers; D058105:Polymerization; D015203:Reproducibility of Results
chemical_list: D003188:Composite Resins; D003764:Dental Materials
keywords: Dental composites; Fiber Bragg grating sensors; Polymerization shrinkage; Thermal expansion coefficient; Water sorption