Fogorvosi szemle, 2014 (107. évfolyam, 1-4. szám)
2014-03-01 / 1. szám
8 — — - FOGORVOSI SZEMLE ■ 107. évf. 1.SZ. 2014. 13. Min S, Ferracane J, Lee I: Effect of shrinkage strain, modulus, and instrument compliance on polymerization shrinkage stress of light-cured composites during the initial curing stage. Dent Mater 2010; 26:1024-1033. 14. Moszner N, Hirt T: New polymer- chemical developments in clinical dental polymer materials: enamel-dentin adhesive and restorative composites. Journal of Polymer Science part A 2012; 50:4369-4402. 15. Reis AF, Giannini M, Ambrosano GM, Chan DC: The effect of filling techniques and a low-viscosity composite liner on bond strength to class II cavities. J Dent 2003; 31:59-66. 16. Satterthwaite JD, Vogel K, Watts DC: Effect of resin composite filler particle size and shape on shrinkage-strain. Dent Mater 2009; 25:1612-1615. 17. Szalóki M, Bukovinszki K, Üveges A, Hegedűs Cs, Borbély J: Fogászati kompozitok gyantájának módosítása reaktív polimer nanorészecskékkel. Fogorv Szle 2007; 100: 307-312. 18. Szalóki M, Gall J, Bukovinszki K, Borbély J, Hegedűs Cs: Synthesis and chracterization of cross-linked polymeric nanoparticles and their composites for reinforcement of photocurable dental resin. Reactive and Functional Polymers 2013; 73: 465- 473. Bukovinszky K, Molnár L, Bakó J, Szalóki M, Hegedűs Cs Comparative study of polymerization shrinkage and related properties of flowable composites and an unfilled resin Objectives: The polymerization shrinkage and shrinkage stress of dental composites are in the center of the interest of researchers and manufacturers. It is a great challenge to minimize this important property as low as possible. Many factors are related and are in complicated correlation with each other affecting the polymerization shrinkage. Polymerization shrinkage stress degree of conversion and elasticity has high importance from this aspect. Our aim was to study the polymerization shrinkage and related properties (modulus of elasticity, degree of conversion, shrinkage stress) of three flowable composite (Charisma Opal Flow, SDR, Filtek Ultimate) and an unfilled composite resin. Materials and methods: Modulus of elasticity was measured using three point flexure tests on universal testing machine. The polymerization shrinkage stress was determined using bonded-disc technique. The degree of conversion measurements were performed by FT-IR spectroscopy. And the volumetric shrinkage was investigated using Archimedes principle and was measured on analytical balance with special additional equipment. Results: The unfilled resin generally showed higher shrinkage (8,26%), shrinkage stress (0,8 MPa) and degree of conversion (38%), and presented the lowest modulus of elasticity (3047,02MPa). Conclusions: Highest values of unfilled resin correspond to the literature. The lack of fillers enlarges the shrinkage, and the shrinkage stress, but gives the higher flexibility and higher degree of conversion. Further investigations needs to be done to understand and reveal the differences between the composites. Key words: polymerization shrinkage, polymerization shrinkage stress, flowable composite, composite resin, modulus of elasticity
