Effects of Two Protocols of Low-Level Laser Therapy on the Proliferation and Differentiation of Human Dental Pulp Stem Cells on Sandblasted Titanium Discs: An In Vitro Study

[摘要] Introduction: Stem cell activities have different effects on tissue response and its outcomes. Lowlevel laser therapy (LLLT) can be considered a trigger to modify stem cell activities. The objectiveof the present experimental investigation was to study the effects of two protocols of LLLT on theproliferation and differentiation of human dental pulp stem cells (hDPSCs) cultured on sandblastedtitanium discs.Methods: Cells obtained from human dental pulp were seeded/cultured on titanium discs and wereset in 2 main groups: (i) Radiated cells using the gallium-aluminium-arsenide (GaAlAs) diode laserat a continuous wavelength of 808 nm at 3 J/cm2 for 12 sec or 5 J/cm2 for 20 seconds, and (ii) Nonirradiated cells serving as control groups. The impact of LLLTs on hDPSC-proliferation and viabilitywas investigated using the MTT assay after 24, 72 and 96 hours. The alkaline phosphatase activitywas studied with p-nitrophenylphosphate after 14 and 28 days. The ability of hDPSCs to expressosteocalcin was investigated using real-time polymerase chain reaction after 28 days, while theirattachment was observed under a scanning electron microscope (SEM) after 14 and 28 days.Results: Our study showed that LLLTs caused maximum cell proliferation in 96 hours (P<0.001)with 3 J/cm2 resulting in a higher proliferation rate. The highest activity of alkaline phosphatase andosteocalcin expression was observed in the laser radiation groups after 28 days.Conclusion: The outcomes of the current study showed that cultured hDPSCs on sandblastedtitanium discs had a tendency towards increased cellular activity in response to LLLTs. Thus, LLLTscould regulate the activities of hDPSCs on bone repair surrounding the sandblasted titanium discs.

[学科分类] 基础医学

[关键词] Differentiation;Low-level laser therapy;Proliferation;Stem cells;Titanium