Is the soft-start polymerisation concept still relevant for modern curing units?
- نوع فایل : کتاب
- زبان : انگلیسی
- مؤلف : Nicoleta Ilie & Esther Jelen & Reinhard Hickel
- چاپ و سال / کشور: 2010
Description
Shrinkage stress, degree of cure and mechanical properties are contradicting properties, forcing to a compromise between an adequate curing and low stress at the interface tooth-restoration. The purpose of this study was to quantify this relations for a micro-hybrid composite, by analysing in real time the development of degree of cure at depths of 2 and 6 mm, shrinkage stress and curing time until gelation, as well as the variation of micro-mechanical properties with depth, after curing with 13 regimes of one halogen and two light-emitting diode (LED) curing units. A nano-dynamic mechanical test was additionally performed on selected regimes (Ramp, Pulse and Fast Cure) of the same curing unit. The present study showed that the softstart polymerization concept is still valid for less deep cavities (2 mm), even by curing with high-power LED curing units, since a soft-cure polymerization resulted in a delayed gel point and a lower shrinkage stress, keeping simultaneously the degree of cure and mechanical properties constant. At 6 mm depth, curing with soft-start regimes resulted in a significant decrease in degree of cure, although this decrease was less than 10%, while the mechanical properties were maintained.
Clin Oral Invest (2011) 15:21–29 DOI 10.1007/s00784-009-0354-5 Received: 6 July 2009 / Accepted: 21 October 2009 / Published online: 24 November 2009
