TABLE 1.
Biological effects of LIPUS on periodontal ligament cells.
| Cell types | Frequency (MHz) | Ultrasound intensity (SATA) | Treatment duration | Main outcomes | References |
|---|---|---|---|---|---|
| PDLFs | 1.5 | 30 mW/cm2 | 20 min/day | Suppresses inflammatory effects of LPS-PG, IL-1β, and TNF-α | Augustine et al. (2021) |
| Promote BMP9-induced osteogenesis through ROCK1 | |||||
| PDLCs | 1.5 | 90 mW/cm2 | 30 min/day | Inhibits IL-6 and IL-8 gene expression | Leewananthawet et al. (2019) |
| Increases expression of osteogenic markers (Runx2, OPN, OSX, and OCN) | |||||
| Inhibits NF-κB signaling pathway | |||||
| PDLCs | 1.5 | 90 mW/cm2 | 20 min/day | Increases mRNA expression of BSP, COL-3, OPN, and calcium deposition | Liu et al. (2020) |
| PDLSCs | 1.0 | 250 and 750 mW/cm2 | 5, 20 min/day | Increases proliferation | Gao et al. (2017) |
| Immediate activation of JNK, MAPK | |||||
| Significant increase in phosphorylated p38 MAPK | |||||
| PDLSCs | 1.5 | 30, 60 and 90 mW/cm2 | 30 min/day | Increases cell migration | Kechagia et al. (2019) |
| Increases the mRNA and protein levels of TWIST1 and SDF-1 | |||||
| PDLCs | 1.5 | 90 mW/cm2 | 20 min/day | Increases osteogenic differentiation (ALP, OCN) and mineralization | Xu et al. (2020) |
| Increases expression of Runx2 and integrin β1 | |||||
| PDLCs | 1.5 | 90 mW/cm2 | 30 min/day | Increases expression of osteogenic markers (ALP, Runx2) and matrix mineralization | Chen et al. (2019c) |
| Inhibits miR-182 expression and promotes FOXO1 accumulation | |||||
| PDLCs | 1.5 | 90 mW/cm2 | 2 h | Increases mRNA and protein expression of autophagic genes Beclin-1 and LC3 | Ying et al. (2020) |
| Decreases IL-6 expression | |||||
| PDLSCs | 1.5 | 90 mW/cm2 | 30 min/day | Increases proliferation, matrix mineralization and osteogenic differentiation (ALP, Runx2) | Li et al. (2020a) |
| Decreases IL-6 and IL-8 expression | |||||
| UPR pathway involved | |||||
| PDLSCs | 1.5 | 90 mW/cm2 | 30 min/day | Increases cell proliferation, matrix mineralization and expression of Runx2, OPN, OCN, COL-1, ALP, integrinβ-1 | Li S. et al. (2021) |
SATA, spatial average temporal average; PDLFs, periodontal ligament fibroblasts; PDLCs, periodontal ligament cells; PDLSCs, periodontal ligament, periodontal ligament stem cells; LPS-PG, porphyromonas gingivalis lipopolysaccharide; IL, interleukin; TNF-α, tumour necrosis factor alpha; BMP, bone morphogenetic protein; ROCK1, rho-associated kinase 1; Runx2, runt-related transcription factor 2; OPN, osteopontin; OSX, osterix; OCN, osteocalcin; NF-κB, nuclear factor-κB; BSP, bone sialoprotein; COL, collagen; JNK, c-Jun NH2-terminal kinase; MAPK, mitogen-activated protein kinases; TWIST1, twist family bHLH, transcription factor 1; SDF-1, stromal cell-derived factor 1; ALP, alkaline phosphatase; FOXO, forkhead box O; LC3, light chain 3; UPR, unfolded protein response.