Polymerisation Shrinkage Profiling of Dental Composites using Optical Fibre Sensing and their Correlation with Degree of Conversion and Curing Rate

Abstract

Traditional polymerisation shrinkage (PS) measurement systems measure average PS of dental composites, but the true local PS varies along the length and breadth of the composite. The PS depends on the curing light intensity distribution, resultant degree of conversion (DOC) and the curing rate. In this paper, optical fibre Bragg grating (FBG) sensing based technology is used to measure the linear post-gel PS at multiple locations within dental composite specimens, and is correlated with DOC and curing rate. A commercial dental composite is used, and its post-gel PS and DOC are mapped using embedded fibre Bragg grating sensors at different curing conditions. The distance between the curing lamp and the composite specimen is varied which resulted in different intensity distribution across the specimen. The effect of curing light intensity distribution on PS, curing rate and DOC are investigated for demonstrating a relationship among them. It is demonstrated that FBG sensing method is an effective method to accurately profiling post-gel PS across the specimen.

Effect of volumetric shrinkage of restorative materials on tooth structure: A finite element analysis

“…Up to the limit of 1%–6% of volumetric shrinkage produced by composite resin materials can be tolerated by the tooth. 26,27 Further, it may lead to iatrogenic errors and associated post-treatment complexities. The polymerization shrinkage stress can be managed by micro root canal access cavity.…”

Digital image correlation in dental materials and related research: A review

“…Polymerization shrinkage of light-cured dental resin composites with resulting contraction stresses has known to be one of the causes for reduced clinical outcome success of those restorations, due to deleterious effects on the integrity of resin-tooth interfaces and mechanical properties of the materials themselves [39,40]. Thus, a wide variety of method or techniques have been developedand applied to the measurement of polymerization contraction shrinkage resulting from light-curing of light-cured dental resin composites, using linear (linometer) [41][42][43] or volumetric shrinkage test systems [44][45][46][47]. polymerization shrinkage of dental composites using optical image correlation method.…”

Design of Polarization-Maintaining FBGs Using Polyimide Films to Improve Strain-Temperature Sensing in CFRP Laminates

“…The fundamental mode 11 is well confined and, by simulation, the presence of the CFRP can be neglected in the 2D-FEM analysis without significant approximation [28]. Considering the small dimensions of an FBG, we can assume that the stress induced by composite material cooling (after curing process) is constant in the FBG region, resulting in the bias of Bragg wavelength not affecting the sensitivity [29]. Therefore, in our model we neglect this effect originated by fabrication process according to [29].…”

“…Considering the small dimensions of an FBG, we can assume that the stress induced by composite material cooling (after curing process) is constant in the FBG region, resulting in the bias of Bragg wavelength not affecting the sensitivity [29]. Therefore, in our model we neglect this effect originated by fabrication process according to [29]. In particular, the use of the relations (7)-(9) allows to describe the refractive index changes considering the influence of strain and temperature.…”