Influence of a blue DPSS laser on specimen thickness of composite resins.
OBJECTIVE
The purpose of the present study was to investigate the effect of 473 nm diode-pumped solid state (DPSS) laser on the curing depth of composite resins.


BACKGROUND
Within the turbid media, light attenuates significantly because of the absorption and scattering.


METHODS
For the study, three different composite resins and light-curing units (LCUs) (a quartz-tungsten-halogen [QTH], light-emitting-diode [LED], and DPSS laser) were used. The number of photons transmitted through the specimens, degree of conversion (DC), microhardness, and refractive index of the specimens on different thicknesses were evaluated.


RESULTS
The incident light exponentially decreased within the specimens. Among the LCUs, QTH showed the least photon loss. The DC obtained using the DPSS laser and QTH was significantly greater (p<0.001) than that obtained using LED. The specimens light cured using the DPSS laser showed slightly lower microhardness than that cured by the other LCUs. On each depth, the mean refractive index was not significantly different for the LCUs used. DC, microhardness, and refractive index had inverse linear correlation with specimen thickness despite exponential decrease of photons number. On the other hand, DC, microhardness, and refractive index were linearly correlated to each other regardless of LCUs.


CONCLUSIONS
The DPSS laser of 473 nm achieved a similar level of polymerization within the specimens as those of the other LCUs even with much lower light intensity. This laser can be applied as a light source for light curing of composite resins.
Department of Dental Materials, School of Dentistry and Medical Research Institute, Pusan National University, Yangsan, Korea.
Dong-In
DI
Yun
Ri-Mo
RM
Ku
Sung-Ae
SA
Son
Jeong-Kil
JK
Park
Ching-Chang
CC
Ko
Hyung-Il
HI
Kim
Yong Hoon
YH
Kwon
D000704:Analysis of Variance; D003188:Composite Resins / Q000737:chemistry / Q000528:radiation effects*; D055117:Curing Lights, Dental; D006244:Hardness; D053844:Lasers, Solid-State; D008422:Materials Testing; D017785:Photons; D012542:Scattering, Radiation
D003188:Composite Resins; C466112:Esthet-X; C533204:filtek Z350; C507210:premise composite resin