Effect of light-curing time on light-cure/post-cure volumetric polymerization shrinkage and regional ultimate tensile strength at different depths of bulk-fill resin composites
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- IDE Kurumi
- Department of Cariology and Operative Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU)
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- NAKAJIMA Masatoshi
- Department of Cariology and Operative Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU)
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- HAYASHI Juri
- Department of Cariology and Operative Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU)
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- HOSAKA Keiichi
- Department of Cariology and Operative Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU)
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- IKEDA Masaomi
- Department of Oral Prosthetic Engineering, Graduate School, Faculty of Dentistry, Tokyo Medical and Dental University (TMDU)
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- SHIMADA Yasushi
- Department of Operative Dentistry, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University
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- FOXTON Richard M.
- Division of Conservative Dentistry, King’s College London Dental Institute at Guy’s, King’s and St Thomas’ Hospitals, King’s College London
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- SUMI Yasunori
- National Center for Geriatrics oand Gerontology, Department of Advanced Dental Research, Center of Advanced Medicine for Dental and Oral Disease
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- TAGAMI Junji
- Department of Cariology and Operative Dentistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU) Global Center of Excellence Program; International Research Center for Molecular Science in Tooth and Bone Diseases, Tokyo Medical and Dental University
Abstract
<p>The aim of this study was to investigate volumetric polymerization shrinkage (VS), using swept-source optical coherence tomography (SS-OCT), of bulk-fill composites with different light-curing strategies; immediately after light-irradiation and after 24 h, and to evaluate their regional ultimate tensile strength (UTS) at different curing depths. The immediate VS after photo-polymerization decreased when the curing light-curing time was reduced from 20 to 10 to 5 s. On the other hand, their VS values after 24 h significantly increased due to the post-cure polymerization, resulting in similar VS values at all the light-curing times. Five seconds light-curing decreased the regional UTS of resin composites after the 24 h period compared with the 10 and 20 s light-curing regimes; therefore, the remarkable progress of post-cure polymerization after light-curing for a short time would not lead to an improvement in the mechanical properties of resin composites. The influence of the light-curing time on the curing depth was dependent upon the bulk-fill composite material.</p>
Journal
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- Dental Materials Journal
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Dental Materials Journal 38 (4), 621-629, 2019-07-26
The Japanese Society for Dental Materials and Devices