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Curing efficiency of various types of light‐curing units
Author(s) -
Rahiotis Chris,
Kakaboura Afrodite,
Loukidis Michalis,
Vougiouklakis George
Publication year - 2004
Publication title -
european journal of oral sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.802
H-Index - 93
eISSN - 1600-0722
pISSN - 0909-8836
DOI - 10.1111/j.0909-8836.2004.00092.x
Subject(s) - curing (chemistry) , materials science , composite material , fourier transform infrared spectroscopy , polymerization , indentation hardness , monomer , composite number , analytical chemistry (journal) , chemistry , polymer , optics , chromatography , microstructure , physics
This study compared monomer conversion (DC), the per cent linear polymerization shrinkage (%LS), the wall‐to‐wall contraction pattern (per cent of peripheral opening, %DM, and maximal marginal gap, MG) and depth of cure (DOC), of a hybrid resin composite (Spectrum TPH) exposed to different types of light‐curing units and exposure modes (Virtuoso‐PAC, Elipar TriLight‐QTH, and FreeLight‐LED). The QTH and LED units were used in two curing modes: the exponential ramp and the continuous output modes. Monomer conversion was investigated by micro Multiple Internal Reflection (MIR)‐Fourier‐transform infrared (FTIR) spectroscopy and %LS was measured by the deflective disc method. The wall‐to‐wall contraction method used a cylindrical cavity model in extracted human teeth. The per cent debonded margins relative to the cavity periphery (%DM) and the width of maximum gap (MG) was evaluated. The DOC was determined using Vickers microhardness measurements (200 g load, 20 s) at the top surface (H 0 ), at 2 mm (H 2 ) and at 4 mm (H 4 ) depths, and the results expressed as H 2 /H 0 and H 4 /H 0 ratios. Significantly lower %DC and %LS values were provided by PAC and LED units. No differences were found in %DM among the curing units and PAC exhibited the highest MG. No significant differences were noted among light‐curing groups in terms of H 2 /H 0 microhardness values. The QTH, operated in exponential mode, resulted in the highest H 4 /H 0 value. The exponential mode of the QTH demonstrated superior performance for the total of the characteristics evaluated.