Cellular Crosstalk Between Periodontal Ligament Fibroblasts and Macrophages: Insights from 2D and 3D Culture Systems in External Inflammatory Root Resorption

Root resorption following traumatic dental injuries is a complex process that involves the breakdown of root dentin and cementum by odontoclasts, which differentiate from precursor macrophages. This differentiation is regulated by periodontal ligament fibroblasts (PDLF). Macrophages can polarize into two types: pro-inflammatory (M1) and anti-inflammatory (M2), which can influence disease progression or the healing process. Under normal circumstances, PDLF maintain the balance of periodontal tissues and the surrounding immune environment. However, during inflammatory conditions such as exposure to bacteria or hypoxia injured PDLF interact with macrophages through signaling mechanisms that promote the differentiation of macrophages into odontoclasts. Various experimental models have been utilized to study the interactions between PDLF and macrophages. This review highlights recent insights into their dynamic relationship in the context of external inflammatory root resorption.