Table 1 . Review of published data in using the effect of Low Level Laser Therapy on proliferation and differentiation of the cells contributing in bone regeneration.
| No | Author & year | Type of LLLT | Type of irradiation | Type of cells | Criteria | Assessment Tests/Assay | Conclusion |
| 1 | Huertas et al.2014 3 | Diode(940 nm) |
Pulsed radiation Energy outputs : 1-5 J Intensities: 0.5, 1, 1.5 and 2 W/cm2 |
MG-63 cell | Cell proliferation | MTT assay | Pulsed low-level laser with low-energy density range appears to exert a biostimulatory effect on bone tissue. |
| 2 | Migliario et al.2014 13 | Diode(980nm) |
Continuous mode Energy outputs: 1-50 J Intensities: 1.57, 7.87, 15.74, 39.37 and 78.75 J/cm2 |
Murine pre-osteoblasts MC3T3 cells | Cell proliferation | Manual cell count | LLLT may be a useful tool for bone regeneration therapy. |
| 3 | Choi et al.2013 17 | He-Ne ( 632.8 nm) |
Continuous mode Energy out puts: 17.0 mW Intensities: 0, 1 and 3 J/cm2 |
Adipose-derived mesenchymal stem cell (ASC) | Osteogenic potential |
-Histological and immunofluorescence assessment -Three-dimensional micro-computed tomography -Western blot analysis |
LLLT enhanced the proliferation and the survival of ASCs at 14 days ASC-seeded grafts promote bone regeneration, and the application of LLLT on ASC-seeded ADM results in rapid bone formation. |
| 4 | Bloise et al.2013 14 | Diode (659 nm) |
Single transverse- mode Energy out puts: 10 mW Intensities: 1 , 3 J/cm2 |
Human osteoblast-like cell line (Saos-2 cell line) | 1.Proliferation 2.Differantiation |
-Calcium deposition -Alkaline phosphatase activity |
LLLT is a helpful application for bone tissue regeneration. |
| 5 | Jawad et al.2013 20 | Diode (940 nm) |
Continuous mode Energy out puts: 100,200,300mw |
Human fetal osteoblast cell line |
1.Proliferation 2.Differantiation |
-MTT assay. -Alkaline phosphatase -Osteocalcin activity assays. |
LLLT may play an important role in stimulating osteoblast cells for improved bone formation. |
| 6 | Wu et al.2013 23 | Diode ( 660 nm) |
Energy out puts: 15 -17 mW⋅cm−2 , Intensities: 1, 2 and 4 J/cm2 |
Human PDL (hPDL) cells |
1.Proliferation 2.Differantiation 3. Osteogenic marker gene expression 4.Cytotoxicity |
-MTT assay -Alizarin Red S staining -Alkaline phosphatase (ALP) activity. -Osteogenic marker gene expression: RT-PCR -Lactate dehydrogenase (LDH) leakage measurement |
Potential use of LPLI in clinical applications for periodontal tissue regeneration. |
| 7 | Pyo et al.2013 21 | Diode (808 nm) |
Continuous mode Energy out puts: 1000 mW Intensities: 1.2, 2.4 and 3.6 J/cm2 |
Hypoxic-cultured Human fetal osteoblast cells (cell line 1.19) | 1.Cell viability 2.Expression of hypoxia-inducible factor-1s (HIF-1s), bone morphogenic protein-2 (BMP-2), osteocalcin, type I collagen, transforming growth factor-β1 (TGF-β1), and Akt |
-MTT assay -Western blot assay -Quantitative reverse transcriptional assay |
LLLT induces the expression of BMP-2, osteocalcin, and TGF- β1 in 1 % hypoxic-cultured human osteoblasts. |
| 8 | Aleksic et al. 2010 25 | Er:YAG laser(2.94nm) |
Pulsed radiation Energy out puts: 30–350 mJ Intensities: 0.7– 17.2J/cm2 |
Mouse-derived osteoblastic cell line MC3T3-E1 |
1. Cell proliferation 2.Cell death 3.Mitogen-activated protein kinase (MAPK) pathways |
- Lactate dehydrogenase measurement -Western blot |
Er:YAG laser may be able to promote bone healing following periodontal and peri implant therapy. |
| 9 | Renno et al.2010 5 | Diode (830 nm) |
Single exposure Energy out puts : 30mW Intensities: 10 J/cm2 |
Osteoblastic (MC3T3) cell line | 1.Proliferation 2.Cell growth | - CellTiter 96Aqueous One Solution Cell Proliferation Assay | Reduction in cell proliferation compared to non-irradiated controls. |
| 10 | Stein et al .2008 22 | 9Diode (670-nm) |
Continuous mode Energy outputs : 400 mW Intensities: 1 or 2 J/cm2 |
Human osteosarcoma cell line SaOS-2 |
1.Total cellular protein synthesis 2.Alkaline phosphatase (ALP)-specific activity 3. attached cell viability |
-Micro BCA™ protein assay -Alkaline phosphatase (ALP)-specific activity:colorimetric end-point assay -Metabolic XTT-Assay |
Combined treatment with phenothiazine chloride and LLLT does not result in a synergistic enhancement of the biostimulatory effect of LLLT. No evidence for antagonizing effects on growth and,differentiation of human osteoblasts. |
| 11 |
Bouvet-Gerbettaz et al. 2009 15 |
Diode (808 nm) |
Continuous mode Intensities: 4 J/cm2 |
Murine bone marrow cells | 1. Bone cell proliferation, 2.Osteoblastic and osteoclastic differentiation |
-Specific staining and microscopic analysis of the culture -Quantitative RT-PCR |
LLLT does not alter murine bone progenitor cell proliferation and differentiation. |
| 12 | Renno et al.2007 26 | (670-nm, 780-nm, and 830-nm) |
Single exposure Energy outputs: 10 mW Intensities: 0.5, 1, 5, and 10 J/cm2 . |
Neonatal, murine, calvarial, osteoblastic (MC3T3) and Human osteosarcoma (MG63) cell lines |
1.Cell proliferation 2.Alkaline phosphatase activity |
-Cell proliferation assay -Alkaline phosphatase assays (EnzoLyteTM pNPP Alkaline Phosphatase Assay (Colorimetric) Kit) |
Each cell line responds differently to specific wavelength and dose combinations. |
| 13 | Martinasso et al .2007 27 | Superpulsed low-level laser therapy (SLLLT) |
Superpulsed radiation Energy outputs: 60 J |
Human osteoblast-like cells MG-63. | 1.Cell proliferation 2. Markers of osteoblast activity |
-Osteocalcin measurement -Alkaline phosphatase measurement -Real time PCR. |
Repeated SLLLT irradiation stimulates cell proliferation in human osteoblast-like cells and, importantly, increases the expression of proteins essential for bone formation. |
| 14 | Aihara et al.2006 16 | Diode laser (810 nm) |
Continuous mode Energy outputs: 50 mW Intensities: 9.33, 27.99, 55.98, or 93.30 J/cm2 , |
Rat osteoclast precursor cells | Formation of osteoclast-like cell |
-Immunohistochemical staining Reverse transcription-polymerase chain reaction -Pit formation assay |
Low-energy laser irradiation facilitates differentiation and activation of osteoclasts via RANK expression. |
| 15 | Stein et al.2005 4 |
He-Ne laser (632 nm) |
energy output: 10mW Intensities: 0.43 J/cm2 |
Human osteoblast cell line |
1.Cell proliferation 2.Differantiation |
-MTT assay - Histochemical staining of ALP - Immunohistochemistry |
LLLT promotes proliferation and maturation of human osteoblasts in vitro. |
| 16 | Hamajima et al.200319 | Diode (830 nm) |
Continuous mode Energy output: 500 mW Intensities: 7.64 J/cm2 , |
Mouse calvaria-derived osteoblastic cell line, MC3T3-E1 | Bone formation |
-Reverse transcription polymerase chain reaction (RT-PCR) method -Real-time PCR method |
Increased expression of the osteoglycin gene by LLLI in the early proliferation stage of cultured osteoblastic cells may play an important role in the stimulation of bone formation in concert with matrix proteins and growth factors. |
| 17 | Coombe et al. 200118 | Diode (830 nm) |
Single radiation Energy output 90 mW Intensities: 1.7 to 25.1 J/cm2 |
Human osteosarcoma cell line, SAOS-2 |
1.Cell viability 2.Proliferation |
-Alkaline phosphatase activity -Intracellular calcium concentration |
The heat shock response and increased intracellular calcium indicate that the cells do respond to low level laser irradiation. |