Table 2.

Research illustrating the ability of dental pulp stem cells to promote nerve regeneration in vitro

Publication year	Cell source	Induction protocol	Material(s) applied	Dose/concentration	Neurocyte type	Culture duration	Results	Ref.
2022	Human	DMEM + 20% (FBS + P/S + AA + bFGF)	Dental pulp cell sheets	3200 cells/cm2	SH-SY5Y neuroblastoma cells	3 d	Dental pulp cell sheets provided neurotrophic support by expressing NTF; the amount of neurotrophic factors produced by dental pulp cell sheets was sufficient to induce nerve regeneration in vitro and promote nerve repair in vivo; dental pulp cell sheets improved axon guidance and reduced axon branching	[113]
2020	Rat	α-MEM + 10% (FBS + P/S + NEAA)	DPSCs-CM	-	TGNCs from rats	3 wk	DPSCs-CM was found to contain significant levels of nerve growth factor, brain-derived neurotrophic factor, neurotrophic factor-3, and glial cell line-derived neurotrophic factor; DPSCs-CM increased the survival rate of primary trigeminal ganglion neurons and promoted the growth of neurites	[130]
2020	Rat	α-MEM + 10% (FBS + P/S + NEAA)	DPSCs-CM	50% DPSCs-CM	PC12 cells	8 d	DPSCs-CM was found to contain neurotrophic factors, brain-derived neurotrophic factor, and glial cell line-derived neurotrophic factor, which increased the viability and differentiation of PC12 cells and played an important role in axonal growth and survival, proving that DPSCs-CM treatment is a potential cell-free therapy for peripheral nerve repair and has a stronger effect on PC12 cells than DPSCs	[115]

AA: Ascorbic acid; bFGF: Basic fibroblast growth factor; DPSCs-CM: DPSCs-conditioned medium; DMEM: Dulbecco’s modified Eagle medium; FBS: Fetal bovine serum; NTF: Neurotrophic factor; NEAA: Nonessential amino acids; P/S: Penicillin and streptomycin; TGNC: Trigeminal ganglion neuronal cells.