engleski

Measurement of linear polymerization contraction using digital laser interferometry

Polymerization shrinkage is an inavoidable consequence of composite resin photopolymerization, as well as one of the most important factors in determining of clinical quality and durability of composite filling. There are many different methods for measuring polymerization shrinkage described in the literature. Digital laser interferometry is a method which enables direct observation of polymerization shrinkage in a real-time. The aim of this study was, by using the method of digital holographic interferometry to measure the linear polymerization contraction of composite materials: Tetric Ceram (Vivadent, Schaan, Liechtenstein), Spectrum TPH (Dentsply, GmbH, Konstanz, Germany) and Valux Plus (3M Dental Procusts, St. Paul, MN) polymerized with three different curing modes of Elipar Trilight (ESPE, Seefeld, Germany) halogen curing unit. The highest polymerization contraction was recorded by "standard mode" (ETS) (1.24 +/- 2.66% lin), and the lowest by "medium mode" (ETM) (0.40 +/- 0.41% lin) during 40 seconds illumination. The "exponentional mode" (ETE) showed the highest expansion during the first 10 second of illumination. Curing units with initial low intensity enable better inner adaptation of composite material, preventing detachment of material from dentin during polymerization and avoiding negative consequences of polymerization shrinkage.

light intensity; polymerization shrinkage; digital laser interferometry; composite resins

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