The dental pulp is a vital component of teeth, providing nourishment and serving as a defense mechanism against potential pathogens. Maintaining the vitality of the dental pulp is crucial for the long-term functionality of teeth [1]. However, when the dental pulp becomes irreversibly inflamed or necrotic due to infections or trauma, root canal treatment (RCT) becomes necessary [2]. Although RCT has shown clinical success, treated teeth can become brittle and prone to fractures or complications such as re-infections [3]. Furthermore, the loss of pulp vitality in young permanent teeth hinders dentine formation and tooth maturation [4]. Thus, more safe and effective approaches are required in endodontics to address these issues and surpass traditional pulp therapies. Tissue engineering in the head and neck region offers numerous advantages, especially in areas such as the tooth and periodontium [5]. The concept of regenerating pulp tissue to revitalize teeth involves disinfecting or debriding infected root canal systems, enlarging the apex to facilitate revascularization, and utilizing tissue-specific stem cells and extracellular matrix (ECM) molecules [6]. This approach, known as regenerative endodontics, aims at replacing diseased or necrotic pulp tissues with regenerated pulp tissue. Researchers and dentists are collaborating to achieve this ambitious goal [2].

PBM therapy has emerged as a potential adjunctive treatment to enhance dental pulp tissue regeneration. Its favorable attributes have earned it recognition as the “fourth element of tissue engineering,” alongside stem cells, scaffolds, and growth factors [7]. PBM therapy, when applied with appropriate parameters, stimulates cell proliferation, differentiation, ATP production, mitochondrial respiration, protein synthesis, and bone formation in cells involved in tissue repair, such as human periodontal ligament stem cells, fibroblasts, and odontoblasts [8].

Present studies have revealed that the TGF-β signaling pathway has a crucial role in controlling the differentiation of stem cells, particularly dental pulp stem cells (DPSCs) [9,10]. TGF-β1 stimulates the proliferation and odontogenic differentiation of DPSCs by modulating the octamer-binding transcription factor 4 (Oct4) and Nanog signaling pathway. These transcription factors maintain the undifferentiated state of DPSCs, and their downregulation during odontoblastic differentiation leads to loss of the stem cells' undifferentiated state. By inhibiting the TGF-β receptor I (TGF-βRI), Oct4 and Nanog expression are increased, preserving the stem cells' pluripotency and preventing lineage differentiation. Therefore, regulating TGF-β signaling, Oct4, and Nanog expression can guide DPSC differentiation towards specific lineages, such as odontoblasts, which can facilitate pulp regeneration and repair [11,12]. Further research is required to understand the precise mechanisms of TGF-β/Oct4/Nanog regulation of DPSC differentiation and how this knowledge can be translated into clinical practice. In general, manipulating TGF-β signaling, Oct4, and Nanog expression holds considerable potential for developing innovative therapies for dental pulp injuries and diseases.

Additionally, dentin matrix is a reservoir for growth factors [13,14], including TGF-β. Chelating solutions like Ethylenediaminetetraacetic acid (EDTA) are suggested to promote the release of growth factors from the dentin matrix and counteract the harmful effects of sodium hypochlorite (NaOCl) on attachment and cell viability [15,16]. However, EDTA has been found to disrupt blood clot formation and cell function, potentially negatively affecting cell attachment and tissue regeneration [17,18].

By investigating the role of PBM therapy in pulp regeneration, researchers aim to uncover its potential as an adjunctive therapy to enhance dental pulp stem cell migration and TGF-β release during regenerative endodontic procedures. This study seeks to shed light on PBM therapy's cellular and molecular mechanisms in regenerative endodontics, providing valuable insights into its effects on pulp regeneration and potentially revolutionizing the field. The findings may lead to a novel and effective approach that expedites tissue engineering processes while minimizing the use of EDTA and its negative impact on dental pulp stem cell viability. However, due to the complexity of PBM therapy's mechanisms and its interactions with DPSCs, a comprehensive understanding is still lacking. Therefore, the present study aims to evaluate the Effect of PBM Therapy on TGF-β Release from Dentin, DPSC migration, and viability in REP.