# High-frequency low-intensity semiconductor laser irradiation enhances osteogenic differentiation of human cementoblast lineage cells

## TL;DR

This study shows that high-frequency laser treatment boosts the bone-forming ability of human cementoblast cells, which could help in regenerating periodontal tissues.

## Contribution

The study demonstrates for the first time that high-frequency semiconductor laser irradiation enhances osteogenic differentiation of human cementoblast lineage cells.

## Key findings

- Laser-irradiated HCEM cells showed significantly higher gene expression of ALP, RUNX2, and COLL1.
- Laser treatment increased ALP activity and calcium concentration in the culture medium.
- Enhanced calcification deposits were observed in laser-irradiated cells at 21 and 28 days.

## Abstract

Laser irradiation activates a range of cellular processes in the periodontal components and promotes tissue repair. However, its effect on osteogenic differentiation of human cementoblast lineage cells remains unclear. This study aimed to examine the effects of high-frequency semiconductor laser irradiation on the osteogenic differentiation of human cementoblast lineage (HCEM) cells.

HCEM cells were cultured to reach 80% confluence and irradiated with a gallium-aluminum-arsenide (Ga-Al-As) semiconductor laser with a pulse width of 200 ns and wavelength of 910 at a dose of 0–2.0 J/cm2. The outcomes were assessed by analyzing the mRNA levels of alkaline phosphatase (ALP), runt-related transcription factor 2 (RUNX2), and type I collagen (COLL1) using real-time polymerase chain reaction (PCR) analysis 24 h after laser irradiation. Cell mineralization was evaluated using ALP activity, calcium deposition, and Alizarin Red staining.

The laser-irradiated HCEM cells showed significantly enhanced gene expression levels of ALP, RUNX2, and COLL1 as well as ALP activity and calcium concentration in the culture medium compared with the non-irradiated cells. In addition, enhanced calcification deposits were confirmed in the laser-irradiated group compared with the non-irradiated group at 21 and 28 days after the induction of osteogenic differentiation.

High-frequency semiconductor laser irradiation enhances the osteogenic differentiation potential of cultured HCEM cells, underscoring its potential utility for periodontal tissue regeneration.