The acceleration of bone regeneration by low-intensity laser irradiation may hold potential benefits in clinical therapy in orthopedics and dentistry. The purpose of this study is to compare the effects of light-emitting diode (LED) and laser on pre-osteoblast MC3T3 proliferation and differentiation. Cells were irradiated with red, infrared, and LED (3 and 5 J/cm(2)). Lasers had a power density of 1 W/cm(2) and irradiation time of 2 and 5 s. LED had a power density of 60 mW/cm(2) and irradiation time of 50 and 83 s. Control group did not receive irradiation. Cell growth was assessed by a colorimetric test (MTT) (24, 48, 72, and 96 h), and cell differentiation was evaluated by alkaline phosphatase (ALP) quantification after growth in osteogenic medium (72 and 96 h and 7 and 14 days). At 24 h, the cell growth was enhanced 3.6 times by LED (5 J/cm(2)), 6.8 times by red laser (3 J/cm(2)), and 10.1 times by red laser (5 J/cm(2)) in relation to control group (p < 0.05). At the other periods, there was no influence of irradiation on cell growth (p > 0.05). The production of ALP was not influenced by irradiation at any period of time (p > 0.05). Low-intensity laser and LED have similar effects on stimulation of cell growth, but no effect on cell differentiation.

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The aim of this study was to investigate the response of osteogenic cell lineage and gingival fibroblastic cells to different surface treatments of grade IV commercially pure Titanium (cpTi) disks. Material and methods: Grade IV cpTi disks with different surfaces were produced: machined (M), sandblasting (B), sandblasting and acid subtraction (NP), and hydrophilic treatment (ACQ). Surface microtopography characteristics and chemical composition were investigated by scanning electron microscopy (SEM) and energy dispersive x-ray spectrometry (EDS). Adhesion and proliferation of SC-EHAD (human surgically-created early healing alveolar defects) and HGF-1 (human gingival fibroblasts) on Ti disks were investigated at 24 and 48 h, and osteogenic differentiation and mineralization were evaluated by assessing alkaline phosphatase (ALP) activity and alizarin red staining, respectively. Results: No significant differences were found among the various surface treatments for all surface roughness parameters, except for skewness of the assessed profile (Rsk) favoring M (p = 0.035 ANOVA). M disks showed a slightly higher (p > 0.05; Kruskal-Wallis/Dunn) adhesion of HGF-1 (89.43 ± 9.13%) than SC-EHAD cells (57.11 ± 17.72%). ACQ showed a significantly higher percentage of SC-EHAD (100%) than HGF-1 (69.67 ± 13.97%) cells adhered at 24 h. SC-EHAD cells expressed increased ALP activity in osteogenic medium at M (213%) and NP (235.04%) surfaces, but higher mineralization activity on ACQ (54.94 ± 4.80%) at 14 days. Conclusion: These findings suggest that surface treatment influences the chemical composition and the adhesion and differentiation of osteogenic cells in vitro. Clinical relevance: Hydrophilic surface treatment of grade IV cpTi disks influences osteogenic cell adhesion and differentiation, which might enhance osseointegration.

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