Scientific reportsSep 4, 2024

Light therapy with 660 and 980 nm lasers may influence how gum ligament stem cells develop

Regenerative Health Weekly Brief ↗PubMed ↗DOI ↗OA ↗

Updated Apr 4, 2026

Abstract

Both 660 and 980 nm diode lasers significantly increased cell viability and differentiation in periodontal ligament after three irradiation cycles.

Cell viability was higher in both laser-treated groups at 4 and 6 days compared to the control group.
The rate of early and late apoptosis was lower in both laser groups at 4 days than in the control group.
Necrosis was less frequent in the 980 nm laser group compared to the control group on day 6.
Higher cell differentiation was observed in both laser groups after three irradiation cycles compared to the control group.
The 660 nm laser group exhibited the highest expression of osteogenic genes after three irradiation cycles.

Simplified

This study aimed to compare the effects of (PBMT) with 660 and 980 nm diode lasers on differentiation of periodontal ligament (PDLMSCs). In this in vitro, experimental study, PDLMSCs were obtained from the Iranian Genetic Bank and cultured in osteogenic medium. They were then subjected to irradiation of 660 and 980 nm diode lasers, and their viability was assessed after one, two, and three irradiation cycles using the methyl thiazolyl tetrazolium (MTT) assay. The cells also underwent DAPI staining, cell apoptosis assay by using the Annexin V/PI, Alizarin Red staining, and real-time polymerase chain reaction (PCR) for assessment of the expression of osteogenic genes. Data were analyzed by two-way ANOVA. The two laser groups had no significant difference in cell apoptosis according to the results of DAPI staining. Both laser groups showed higher cell viability in the MTT assay at 4 and 6 days compared with the control group. Annexin V/PI results showed higher cell viability in both laser groups at 4 days compared with the control group. Rate of early and late apoptosis was lower in both laser groups than the control group at 4 days. Necrosis had a lower frequency in 980 nm laser group than the control group on day 6. Alizarin Red staining showed higher cell differentiation in both laser groups after 3 irradiation cycles than the control group. The highest expression of osteopontin (OPN), osteocalcin (OCN), and Runt-related transcription factor 2 (RUNX2) was noted in 660 nm laser group with 3 irradiation cycles at 14 days, compared with the control group. PBMT with 660 and 980 nm diode lasers decreased apoptosis and significantly increased PDLMSC differentiation after 3 irradiation cycles.

Key numbers

660 nm 117.375

Increase in Cell Viability

Mean cell viability (optical density) after 2 irradiation cycles.

3 of 3

Higher Cell Differentiation

Cell differentiation assessed via Alizarin Red staining.

OPN 14 days

Osteogenic Gene Expression

Highest expression of OPN, OCN, and RUNX2 at day 14.

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Light therapy with 660 and 980 nm lasers may influence how gum ligament stem cells develop

Abstract

Key numbers

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