ment and bone graft using deproteinized bovine bone and recognized that these circumstances were nothing
more than intentional controlled overpressure against static cells since this controlled trauma could affect cell
function/malfunction, or cell recovery/apoptosis. The present preliminary study was conducted to prove if LLL
would influence cell viability and cell function after excessive damage, which is enough to diminish cell num-
bers and distort the features of cells. Our aim is to evaluate whether low level laser irradiation (LLLi) could be
helpful in the recovery of traumatized osteoblasts (pressure damaged cells) by observing the morphology and
the survival rate of those cells. This model used bone cell cultures which were traumatized by a pressure with
250 G of centripetal force and observed their response to such trauma and low level laser irradiation. In this
experiment, a Ga–Al–As diode LLL (IMPRA-ORT, NDLux, Seoul, KOREA) was used with a wavelength of
808 nm, a focus of 14
24 mm, which was wide enough to cover the whole dish surface or well within at least 2 times radiation, and an output of 100 mW. Statistical analysis showed a higher recovery rate of damaged
osteoblasts in the radiation group than the non-radiation group (p < 0.05). The nonradiation group had a very
poor proliferation rate in comparison to the control group (p < 0.05) in every time period. In the control group,
actin filaments showed a random orientation and cell process branched variously around each cell. In contrast,
compressed cells, these patterns were turned into thicker and shorter cytoskeletons. As time progressed, every
living cell recovered from the severe stress and recovered both form and function. In summary, the present study
showed the capacity of LLLT to aid the recovery of the cell skeleton and affect cell viability on overpressured
osteoblasts. These results may contribute toward a better understanding of the effect of LLLT on the recovery
of cells after trauma. In addition, our results demonstrated that LLLT could be used in the field of bone tissue
engineering to traumatized bone conditions and repair large bone defects such as bone graft and implant instal-
lation.