Optimizing neurogenic differentiation of dental stem cells: a critical review of induction strategies and functional validation.

Abstract

Neurogenesis is highly active during brain development but becomes substantially restricted in adulthood. Therefore, the nervous system shows a limited ability to self-renew succeeding a traumatic incident or neurodegenerative disease. Dental stem cells (DSCs) represent a unique population of mesenchymal stem cells originating from the cranial neural crest. Thus, they have an inherent capacity to differentiate into neurons under proper in vitro cues. However, this ability is limited by low conversion rates and unpredictable target cell types, along with a noticeable lack of standardized differentiation protocols. Therefore, the primary aim of this critical narrative review is to evaluate, categorize, and critique the neurogenic induction strategies for human dental stem cells reported over the last ten years. By analyzing the current literature, differentiation protocols can be broadly categorized into three distinct approaches: growth factors, small molecules, and combination of both. Although the combined strategy shows a promising potential, the focus on structural outcomes and the absence of electrophysiological validation make it hard to determine which protocol truly generates functional neurons. Moreover, in the few protocols that provided differentiation evidence across morphological, molecular, and functional endpoints, the resulting cells displayed only partial functional maturation, indicating that the generation of fully mature neurons remains challenging in vitro. Moving forward, future studies should incorporate patch-clamp electrophysiology as a standard component of functional validation to determine whether differentiated cells acquire genuine neuronal excitability and to strengthen the evidence required for clinical translation.