[Polymerization of flowable composite core materials irradiated by super-high intensity light with short time].
OBJECTIVE
To evaluate the polymerization of dual-cured flowable composite core irradiated by super-high intensity light with short time.


METHODS
The light-proof silicon rubber cuboid mold with one end open was syringed and filled by dual-cured flowable resin composite core, then the open end of mold was irradiated directly by a light unit at 1000 mW/cm(2) ×10, ×20 s; or at 3200 mW/cm(2) × 3, ×6 s. The specimens were stored in the light-proof box. After irradiation for 1 h and 24 h, Knoop microhardness was measured along the vertical surfaces of specimens from 1mm to 10 mm depth at 1 mm interval. The data was analyzed by one-way ANOVA with SPSS 16.0 software package.


RESULTS
3200 mW/cm(2) ×3 s light irradiation did not initiate light curing of the specimens. The other three light irradiations could make specimens obtaining higher microhardness than that by pure chemical cure; however, the depth of specimens affected by light irradiation was limited. Within the area affected by light, the microhardness of specimens could be improved by increasing the light irradiation time; after irradiation for 24 h, the microhardness of specimens had no difference between 3200 mW/cm(2) ×6 s and 1000 mW/cm(2) ×20 s light irradiation.


CONCLUSIONS
3200 mW/cm(2) light intensity should be used for irradiation at least for 6 s, which could initiate light curing of flowable composite core to sufficient polymerization.
Department of Prosthodontics, Nanjing Stomatological Hospital & Stomatological Hospital Affiliated to Medical School, Nanjing University. Nanjing 210008, Jiangsu Province, China. E-mail:swhnanda@163.com.
Shao-Wei
SW
He
Teng-Yu
TY
Geng
Xiang-Feng
XF
Meng
D003188:Composite Resins; D055117:Curing Lights, Dental; D006244:Hardness; D008027:Light; D008422:Materials Testing; D058105:Polymerization; D013499:Surface Properties; D013997:Time Factors
D003188:Composite Resins; C111840:flowable hybrid composite