Orthodontic Force Induces Systemic Inflammatory Monocyte Responses

Abstract

Periodontal inflammation and alveolar bone remodeling during orthodontic tooth movement are considered regional reactions. However, how systemic immune responses are involved in this regional reaction remains unclear. In this study, we explored the systemic effects of orthodontic force by focusing on the mononuclear phagocyte system. Flow cytometric analysis showed that the percentage of inflammatory monocytes, in peripheral blood and in the monocyte reservoir spleen, decreased on days 1 and 3 and then recovered on day 7 after force application. Along with the systemic decrease of inflammatory monocyte percentage, the number of tartrate-resistant acid phosphatase-positive osteoclasts increased in the compression side of the periodontal tissue during orthodontic tooth movement. Systemic transfusion of enhanced green fluorescent protein-labeled inflammatory monocytes showed recruitment of these monocytes to the orthodontic force compression side of periodontal tissues. These monocytes were colocalized with tartrate-resistant acid phosphatase-positive osteoclasts. In vivo and in vitro experiments showed that orthodontic force could upregulate the expression of pivotal monocyte chemokine monocyte chemotactic protein 1 in periodontal tissues or cultured periodontal ligament cells, which may contribute to monocyte recruitment to regional sites. These data suggest that orthodontic force induces systemic immune responses related to inflammatory monocytes and that systemic inflammatory monocytes can be recruited to periodontal tissues by orthodontic force stimulus.

Antibiotic administration alleviates the aggravating effect of orthodontic force on ligature‐induced experimental periodontitis bone loss in mice

“…Indeed, recent evidence suggested that the use of topical as well as SAs is an effective adjunct to the non‐surgical periodontal treatment to suppress periodontopathogens and promote anti‐inflammatory activity . Recent studies have indicated that OF induces systemic immune responses related to monocytes and T cells . Our finding is consistent with these studies demonstrating the elevated levels of serum total IgG when OF was applied in groups 2 and 3 (Fig.…”

MicroRNA‐21 promotes orthodontic tooth movement by modulating the RANKL/OPG balance in T cells

“…The animals ( n = 6/group, 20–25 g) were anesthetized with chloral hydrate (40 mg/kg), and orthodontic force was applied as previously described (Yan et al, ). A nickel‐titanium coiled spring (wire size, 0.2 mm; diameter and length, 1 mm; Tomy International, Inc., Japan) provided 30–35 g of force (Taddei et al, ) between the incisor and the left maxillary first molar of the mouse (Zeng et al, ), and a flowable restorative resin (3M ESPE, MN, USA) was used to bond the spring (Figure b). After surgery, the mice had free access to soft food and water.…”

Current advances in orthodontic pain

“… 34 , 35 Once periodontal vascular permeability increases, abundant leucocytes, including neutrophils, monocytes and lymphocytes, are recruited to periodontal tissues. 36 , 37 , 38 , 39 , 40 Upon activation at periodontal tissues, these cells release various chemokines, cytokines and inflammatory mediators that further amplify local inflammation and cause a painful sensation. 33 , 41 …”

“…Once local inflammation occurs, vascular permeability increases and numerous leucocytes, including neutrophils, mast cells, macrophages, T cells and monocytes, are recruited and infiltrate periodontal tissues. 36 , 37 , 38 , 39 , 40 In response to local inflammation, periodontal mast cells and macrophages release various mediators that facilitate leucocyte recruitment to periodontal tissues. 42 Among these mediators, histamine and tumour necrosis factor-alpha (TNF-α) released from mast cells stimulate adhesion protein upregulation in vascular endothelial cells.…”