TY - JOUR
T1 - 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
AU - Ide, Kurumi
AU - Nakajima, Masatoshi
AU - Hayashi, Juri
AU - Hosaka, Keiichi
AU - Ikeda, Masaomi
AU - Shimada, Yasushi
AU - Foxton, Richard M.
AU - Sumi, Yasunori
AU - Tagami, Junji
PY - 2019/1/1
Y1 - 2019/1/1
N2 - 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.
AB - 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.
KW - Bulk fill
KW - Depth of cure
KW - Optical coherence tomography
KW - Ultimate tensile strength
KW - Volumetric shrinkage
UR - http://www.scopus.com/inward/record.url?scp=85070848547&partnerID=8YFLogxK
U2 - 10.4012/dmj.2018-279
DO - 10.4012/dmj.2018-279
M3 - Article
C2 - 31178547
AN - SCOPUS:85070848547
SN - 0287-4547
VL - 38
SP - 621
EP - 629
JO - Dental Materials Journal
JF - Dental Materials Journal
IS - 4
ER -