Question: What is the mechanism of cementogenesis in pulp regeneration?

Context:
New vital tissues can be regenerated in permanent canine teeth after pulpectomy and enlargement of the apical foramen
The loss of dental pulp may weaken teeth, rendering them susceptible to reinfection, fracture, and subsequent tooth loss. Therefore, regeneration of pulp is considered an ideal treatment to preserve teeth.
Constitutive stabilization of ß-catenin in the dental mesenchyme leads to excessive dentin and cementum formation
Wnt/ß-catenin signaling plays an important role in morphogenesis and cellular differentiation during development. Essential roles of Wnt/ß-catenin signaling in tooth morphogenesis have been well known
Our results indicate that persistent stabilization of ß-catenin in the dental mesenchyme leads to premature differentiation of odontoblasts and differentiation of cementoblasts, and induces excessive dentin and cementum formation in vivo. These results suggest that temporospatial regulation of Wnt/ß-catenin signaling plays critical roles in the differentiation of odontoblasts and cementoblasts, and that inhibition of Wnt/ß-catenin signaling may be important for the formation of dentin and cementum during tooth development
Local modulation of Wnt/ß-catenin signaling has therapeutic potential to improve the regeneration of dentin and periodontium
It is known that the dental follicle (DF) consists of progenitor cells that give rise to the cementum, periodontal ligament, and alveolar bone
 but little information is available about the regulation of DF cell differentiation into either cementogenic or osteogenic cell lineages for the regeneration of diseased periodontal tissue. Here, we investigated the roles of DF, Hertwig's epithelial root sheath (HERS), and pulp cells in the cementum
These results suggest that the combined use of DF, HERS, and pulp cells could direct DF cell differentiation into cementoblasts and/or osteoblasts in vivo, thus providing a novel strategy for the successful repair and regeneration of diseased periodontal tissue
 HERS cells played a role in the induction and maturation of cementum-like tissues formed by DF cells
 implants of DF cells in the presence of pulp cells led to the formation of bone-like tissues
Interestingly, in the presence of both HERS and pulp cells, DF cells formed both cementum-like and bone-like tissues. We demonstrated that while HERS cells are able to induce DF cell differentiation into cementoblasts and promote cementum formation, pulp cells could direct DF cell differentiation into osteoblasts and enhance alveolar bone formation
Periodontal ligament (PDL) and cementum complex and dentin pulp complex have been tissue engineered using human dental pulp stem cells and PDL stem cells
Histological, immunohistochemical, and scanning electronic microscopy examinations results showed that bioengineered dentin could induce cementogenesis and PDL formation, and condense PDL arranged perpendicularly on the dentin surface via a layer of cementum-like tissue

Answer: The dental follicle (DF) consists of progenitor cells that give rise to the cementum, periodontal ligament, and alveolar bone.  Dental follicle cells attach to Hertwig's epithelial root sheath (HERS), and pulp cells in the cementum promoting cementogenesis. The  temporospatial regulation of Wnt/ß-catenin signaling plays critical roles in the differentiation of odontoblasts and cementoblasts.
Our results indicate that persistent stabilization of ß-catenin in the dental mesenchyme leads to premature differentiation of odontoblasts and differentiation of cementoblasts, and induces excessive dentin and cementum formation in vivo. It is known that the dental follicle (DF) consists of progenitor cells that give rise to the cementum, periodontal ligament, and alveolar bone. Wnt/ß-catenin signaling plays an important role in morphogenesis and cellular differentiation during development. New vital tissues can be regenerated in permanent canine teeth after pulpectomy and enlargement of the apical foramen. Constitutive stabilization of ß-catenin in the dental mesenchyme leads to excessive dentin and cementum formation. These results suggest that temporospatial regulation of Wnt/ß-catenin signaling plays critical roles in the differentiation of odontoblasts and cementoblasts, and that inhibition of Wnt/ß-catenin signaling may be important for the formation of dentin and cementum during tooth development. HERS cells played a role in the induction and maturation of cementum-like tissues formed by DF cells. Essential roles of Wnt/ß-catenin signaling in tooth morphogenesis have been well known.