TNF-α Aggravates the Progression of Orthodontically-induced Inflammatory Root Resorption in the Presence of RANKL

Abstract

Orthodontically-induced inflammatory root resorption (OIIRR) is one of the procedure-related adverse effects that occur during orthodontic treatment, and the incidence is related to the proinflammatory cytokine produced in response to the mechanical stress caused by the procedure. It is known that tumor necrosis factor (TNF)-is produced following environmental insults in vivo at an early stage, and that it deeply affects inflammatory bone resorption. However, the relationship between the TNF-level and root resorption is unclear. In this study, the relationship between TNF-and root resorption was evaluated using an experimental mouse tooth movement model and a pressure side model using human periodontal ligament (hPDL) cells, as well as an osteoclast culture system. Nine days after the tooth movement in the mouse model, an increase in TNFand receptor activator of nuclear factor-B ligand (RANKL) positive cells was observed. In vitro, their levels increased in the cultures of hPDL cells exposed to the 4 g/cm 2 pressure. In addition, the differentiation of osteo/ odontoclasts was promoted by TNF-weakly, but the ability to resorb the dentin was unchanged. However, the activation of osteo/odontoclastogenesis is more potent in the presence of RANKL and TNF-, which leads to synergistic activation. These results suggest that TNF-may be an aggravating factor for root resorption during orthodontic treatment.

<b>Caspase-mediated Apoptosis by Compressive Force Induces RANKL in Cementoblasts </b>

“…These findings suggest that root resorption is caused not only by apoptosis but also by other factors. Recent studies in this vein are investigating the involvement of TNF-and Notch signaling in exacerbation of root resorption, which are also suggested to increase RANKL (21,22).…”

Root Resorption in Streptozotocin-induced Diabetic Rats with Ligature-induced Periodontitis

“…The expression of TNF-α and RANKL increased in the gingival crevicular fluid of patients with severe root resorption after orthodontic treatment, suggesting that TNFα and RANKL may play important roles in orthodontically induced inflammatory root resorption [18]. Also, an in vitro study showed that odontoclast formation by RANKL was more potent in the presence of TNF-α, indicating that TNF-α may aggravate root resorption during orthodontic treatment [8]. These findings imply that higher TNF-α and RANKL expression in the PD group could be related to increased root resorption.…”

“…Enzymatic properties of odontoclasts are similar to those of osteoclasts in terms of expression of H + -ATPase, cathepsin K, and matrix metalloprotease-9 [2]. In addition, it has been reported that osteoclast differentiation factors can induce odontoclast formation, including receptor activator of nuclear factor-κB ligand (RANKL) and tumor necrosis factor (TNF)-α [2,8].…”

Jiggling Force Aggravates Orthodontic Root Resorption Via TNF-α during Rat Experimental Tooth Movement

“…Furthermore, recent studies reported that a heavy force induced ORR via the expression of tumor necrosis factor (TNF)-α from PDL cells (7), that the levels of TNF-α in the gingival crevicular fluid(GCF)in patients with severe root resorption after orthodontic treatment.…”