title: Time-resolved simultaneous measurement of group index and physical thickness during photopolymerization of resin-based dental composite.
abstract: Light-activated resin-based dental composites are increasingly replacing dental amalgam. However, these materials are limited by inefficient setting reactions as a function of depth that constrain the maximum extent of cure. Insufficient curing can contribute to an overall reduction in biocompatibility of the material. We demonstrate dynamic refractive index measurements of a commercial dental composite throughout cure using spectral domain low coherence interferometry. Our results show a linear relationship between the change in refractive index and polymerization-induced reduction in physical thickness during light-activated curing. This relationship between the optical and physical density demonstrates the potential of this technique as a unique noninvasive tool for measurement of the conversion degree of curing dental composite materials.
authors.affiliation: National Physical Laboratory, Photonics Group, Hampton Road, Teddington, Middlesex TW11 0LW, United Kingdom. pete.tomlins@npl.co.uk
authors.forename: Peter H
authors.initials: PH
authors.lastname: Tomlins
authors.forename: Will M
authors.initials: WM
authors.lastname: Palin
authors.forename: Adrian C
authors.initials: AC
authors.lastname: Shortall
authors.forename: Ruikang K
authors.initials: RK
authors.lastname: Wang
mesh_terms: D003188:Composite Resins / Q000737:chemistry*; D007368:Interferometry / Q000379:methods*; D008422:Materials Testing / Q000379:methods*; D010777:Photochemistry / Q000379:methods; D012031:Refractometry / Q000379:methods; D041623:Tomography, Optical Coherence / Q000379:methods*
chemical_list: D003188:Composite Resins