• Bociong, Kinga
• Szczesio, Agata
• Łukomska-Szymańska, Monika
• Sokołowski, Jerzy
• Krasowski, Michał
• Domarecka, Monika
• Sokołowski, Krzysztof

Abstract

Introduction. The elimination or reduction ofshrinkage stress is one of the major problems in thedevelopment of dental composites. Sorption of waterby resin fillings in the moist environment of the oralcavity and in consequence its volume expansionshould counteract the observed shrinkage contraction.Aim of the study. To evaluate the influence of watersorption in resin-based materials on polymerizationshrinkage stress generated on the restoration-toothinterface. Material and methods. The shrinkage stresswas measured immediately after curing. The samplesstored in water were evaluated after 24 h for 7 daysand then once a week up to 90 days. Photoelastic studywas performed on photosensitive epoxy resin platesin Transmission Polariscope FL200. The study wasbased on the analysis of dimension and arrangement offringes. Contraction stress was calculated on the basisof photoelastic theory. In order to measure the watersorption and its dynamics, the material samples wereweighed on analytical scale in the above mentionedtime intervals. Results. The tested materials duringpolymerization generated shrinkage stresses rangingfrom 6 to 17 MPa. After conditioning in water, the decrease in shrinkage strain after 72 h was observed.The decrease in value stress in time depended on thetype of material. Conclusions. Polymerizing dentalmaterials generated differentiated shrinkage stressthat decreased in time due to water sorption. Thedynamics of stress change is material dependant

Topics

• impedance spectroscopy
• theory
• composite
• resin
• curing