Original scientific paper
Degree of Conversion and Temperature Increase During Composite Polymerisation with LED Units of Different Intensity
Alena Knežević
; School of Dental Medicine, University of Zagreb, Zagreb, Croatia
Mira Ristić
; Ruđer Bošković Institute, Zagreb, Croatia
Zrinka Tarle
; School of Dental Medicine, University of Zagreb, Zagreb, Croatia
Goran Pichler
; Institute of physics, Zagreb, Croatia
Svetozar Musić
; Ruđer Bošković Institute, Zagreb, Croatia
Abstract
The appearance of LED curing units for composite materials polymerization has almost completely replaced halogen curing units. The main disadvantage of halogen curing units was a temperature rise during the polymerization. Earlier generations of LED devices made the temperature rise negligible. The newest generation of LED curing units makes a higher degree of conversion due to higher light intensity, but also brings to question the temperature rise during the composite materials polymerization. Aim: The purpose of this study was to measure the degree of conversion and temperature rise in composite resin samples. Material and Methods: The samples were polymerized by curing modes of different light intensity of four LED units: Bluephase, Bluephase C5, Bluephase C8 and Bluephase 16i (all units Vivadent, Schaan, Liechtenstein). The degree of conversion was measured by FTIR spectrophotometer, while for the temperature it was measured using the thermometer ELV Pyroscan (Leer, Germany). Results: The highest degree of conversion was achieved in the case of composite resin samples polymerized with soft-start mode (SOFT) of Bluephase 16i unit, while the lowest degree of conversion was achieved in the case of polymerization with Bluephase C5 curing unit. The highest temperature rise was recorded in the case of composite samples polymerization with high intensity mode (HIGH) and SOFT mode of Bluephase 16i, while the lowest in the case of polymerization with low intensity mode (LOW) of Bluephase C8 unit. Conclusion: According to the results of this study, it can be concluded that higher degree of conversion brings higher temperature rise, regardless of composite material used.
Keywords
Hrčak ID:
21184
URI
Publication date:
15.3.2008.
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