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Dental Clinics of North America Oct 2022As a widespread chronical disease, periodontitis progressively destroys tooth-supporting structures (periodontium) and eventually leads to tooth loss. Therefore,... (Review)
Review
As a widespread chronical disease, periodontitis progressively destroys tooth-supporting structures (periodontium) and eventually leads to tooth loss. Therefore, regeneration of damaged/lost periodontal tissues has been a major subject in periodontal research. During periodontal tissue regeneration, biomaterials play pivotal roles in improving the outcome of the periodontal therapy. With the advancement of biomaterial science and engineering in recent years, new biomimetic materials and scaffolding fabrication technologies have been proposed for periodontal tissue regeneration. This article summarizes recent progress in periodontal tissue regeneration from a biomaterial perspective. First, various guide tissue regeneration/guide bone regeneration membranes and grafting biomaterials for periodontal tissue regeneration are overviewed. Next, the recent development of multifunctional scaffolding biomaterials for alveolar bone/periodontal ligament/cementum regeneration is summarized. Finally, clinical care points and perspectives on the use of biomimetic scaffolding materials to reconstruct the hierarchical periodontal tissues are provided.
Topics: Biocompatible Materials; Guided Tissue Regeneration, Periodontal; Humans; Periodontal Ligament; Periodontium; Tissue Engineering
PubMed: 36216452
DOI: 10.1016/j.cden.2022.05.011 -
International Journal of Oral Science Jun 2021Nowadays, orthodontic treatment has become increasingly popular. However, the biological mechanisms of orthodontic tooth movement (OTM) have not been fully elucidated.... (Review)
Review
Nowadays, orthodontic treatment has become increasingly popular. However, the biological mechanisms of orthodontic tooth movement (OTM) have not been fully elucidated. We were aiming to summarize the evidences regarding the mechanisms of OTM. Firstly, we introduced the research models as a basis for further discussion of mechanisms. Secondly, we proposed a new hypothesis regarding the primary roles of periodontal ligament cells (PDLCs) and osteocytes involved in OTM mechanisms and summarized the biomechanical and biological responses of the periodontium in OTM through four steps, basically in OTM temporal sequences, as follows: (1) Extracellular mechanobiology of periodontium: biological, mechanical, and material changes of acellular components in periodontium under orthodontic forces were introduced. (2) Cell strain: the sensing, transduction, and regulation of mechanical stimuli in PDLCs and osteocytes. (3) Cell activation and differentiation: the activation and differentiation mechanisms of osteoblast and osteoclast, the force-induced sterile inflammation, and the communication networks consisting of sensors and effectors. (4) Tissue remodeling: the remodeling of bone and periodontal ligament (PDL) in the compression side and tension side responding to mechanical stimuli and root resorption. Lastly, we talked about the clinical implications of the updated OTM mechanisms, regarding optimal orthodontic force (OOF), acceleration of OTM, and prevention of root resorption.
Topics: Humans; Osteoblasts; Osteoclasts; Periodontal Ligament; Periodontium; Root Resorption; Tooth Movement Techniques
PubMed: 34183652
DOI: 10.1038/s41368-021-00125-5 -
Tissue Engineering. Part C, Methods Aug 2022Periodontitis is a chronic infectious oral disease with a high prevalence rate in the world, and is a major cause of tooth loss. Nowadays, people have realized that the... (Review)
Review
Periodontitis is a chronic infectious oral disease with a high prevalence rate in the world, and is a major cause of tooth loss. Nowadays, people have realized that the local microenvironment that includes proteins, cytokines, and extracellular matrix has a key influence on the functions of host immune cells and periodontal ligament (PDL) stem cells during a chronic infectious disease such as periodontitis. The above pathological process of periodontitis will lead to a defect of periodontal tissues. Through the application of biomaterials, biological agents, and stem cell therapy, guided tissue regeneration (GTR) makes it possible to reconstruct healthy PDL tissue after local inflammation control. To date, substantial advances have been made in periodontal GTR. However, the process of periodontal remodeling experiences complex microenvironment changes, and currently periodontium regeneration still remains to be a challenging feat. In this review, we summarized the main challenges in each stage of periodontal regeneration, and try to put forward appropriate biomaterial treatment mechanisms or potential tissue engineering strategies that provide a theoretical basis for periodontal tissue engineering regeneration research.
Topics: Biocompatible Materials; Guided Tissue Regeneration, Periodontal; Humans; Periodontal Ligament; Periodontitis; Periodontium; Tissue Engineering
PubMed: 35838120
DOI: 10.1089/ten.TEC.2022.0106 -
Acta Biomaterialia Mar 2022Periodontitis is the primary cause of tooth loss, but there is no effective treatment to repair inflammatory bone loss in periodontitis. Exosomes emerge as essential...
Periodontitis is the primary cause of tooth loss, but there is no effective treatment to repair inflammatory bone loss in periodontitis. Exosomes emerge as essential paracrine factors of mesenchymal stem cells (MSCs) that mediated tissue regeneration. Here, we investigated the potential of exosomes secreted by periodontal ligament stem cells (PDLSCs) as therapeutics for the bone defect in periodontitis. Exosomes secreted from PDLSCs derived from healthy periodontal ligaments (h-PDLSCs) and their function were evaluated on PDLSCs isolated from the inflammatory periodontal ligament of periodontitis patients (i-PDLSCs). Treatment of exosomes of h-PDLSCs led to an increase in the formation of mineralized nodules and the expressions of osteogenic genes and proteins in i-PDLSCs. Mechanistically, h-PDLSCs-exosomes suppressed the over-activation of canonical Wnt signaling to recover the osteogenic differentiation capacity of i-PDLSCs. To evaluate the therapeutic of exosomes on inflammatory bone loss, h-PDLSCs-exosomes loaded with Matrigel or β-TCP were employed to repair bone defects in rat models of periodontitis. Compared to the vehicle-treated control group, h-PDLSCs-exosomes-treated rats resulted in more bone formation in the defect of alveolar bone. In conclusion, these results demonstrated that exosomes derived from healthy PDLSCs could rescue the osteogenesis capacity of endogenous stem cells under an inflammatory environment and promote regeneration of alveolar bone. Our findings suggest that MSCs-derived exosome is an effective and practical cell-free MSC therapeutic for the treatment of periodontitis. STATEMENT OF SIGNIFICANCE: There is no effective treatment to repair inflammatory bone loss in periodontitis. As essential paracrine factors of PDLSCs, exosomes might mediate tissue regeneration during stem cell therapy. Here, we reported that exosomes secreted from healthy PDLSCs promoted the osteogenic differentiation of PDLSCs derived from periodontitis tissue. Healthy PDLSCs-exosomes treatment resulted in accelerated bone formation in the defect of alveolar bone in rat models of periodontitis. Mechanistically, h-PDLSCs-exosomes suppressed the over-activation of canonical Wnt signaling to recover the osteogenic differentiation capacity of inflammatory PDLSCs. These findings suggest that MSCs-derived exosome is an effective and practical cell-free MSC therapeutic for the treatment of periodontitis.
Topics: Animals; Exosomes; Humans; Osteogenesis; Periodontal Ligament; Periodontitis; Rats; Stem Cells
PubMed: 34979326
DOI: 10.1016/j.actbio.2021.12.035 -
Clinical Oral Investigations Jan 2022The aim of this in vitro and in vivo study was to investigate the interaction of periodontitis and orthodontic tooth movement on interleukin (IL)-6 and C-X-C motif...
OBJECTIVES
The aim of this in vitro and in vivo study was to investigate the interaction of periodontitis and orthodontic tooth movement on interleukin (IL)-6 and C-X-C motif chemokine 2 (CXCL2).
MATERIALS AND METHODS
The effect of periodontitis and/or orthodontic tooth movement (OTM) on alveolar bone and gingival IL-6 and CXCL2 expressions was studied in rats by histology and RT-PCR, respectively. The animals were assigned to four groups (control, periodontitis, OTM, and combination of periodontitis and OTM). The IL-6 and CXCL2 levels were also studied in human gingival biopsies from periodontally healthy and periodontitis subjects by RT-PCR and immunohistochemistry. Additionally, the synthesis of IL-6 and CXCL2 in response to the periodontopathogen Fusobacterium nucleatum and/or mechanical strain was studied in periodontal fibroblasts by RT-PCR and ELISA.
RESULTS
Periodontitis caused an increase in gingival levels of IL-6 and CXCL2 in the animal model. Moreover, orthodontic tooth movement further enhanced the bacteria-induced periodontal destruction and gingival IL-6 gene expression. Elevated IL-6 and CXCL2 gingival levels were also found in human periodontitis. Furthermore, mechanical strain increased the stimulatory effect of F. nucleatum on IL-6 protein in vitro.
CONCLUSIONS
Our study suggests that orthodontic tooth movement can enhance bacteria-induced periodontal inflammation and thus destruction and that IL-6 may play a pivotal role in this process.
CLINICAL RELEVANCE
Orthodontic tooth movement should only be performed after periodontal therapy. In case of periodontitis relapse, orthodontic therapy should be suspended until the periodontal inflammation has been successfully treated and thus the periodontal disease is controlled again.
Topics: Animals; Fusobacterium nucleatum; Gingiva; Periodontal Ligament; Periodontitis; Rats; Tooth Movement Techniques
PubMed: 34024010
DOI: 10.1007/s00784-021-03988-4 -
Scientific Reports Jun 2020To evaluate tooth behaviours under various maxillary incisor retraction protocols for clear aligner therapy. A three-dimensional finite element model of maxillary...
To evaluate tooth behaviours under various maxillary incisor retraction protocols for clear aligner therapy. A three-dimensional finite element model of maxillary dentition was constructed for first premolar extraction. A loading method was developed to mimic the mode of action of clear aligners for incisor en masse retraction. Three protocols with different amounts of retraction and intrusion on incisors were designed. Initial tooth displacements and stresses on periodontal ligaments were analysed with ANSYS software. The central (U) and lateral (U) incisors exhibited uncontrolled lingual tipping and extrusion upon 0.25 mm retraction. U1 exhibited translation movement, while U underwent less tipping during 0.2 mm retraction and 0.15 mm intrusion. Labial tipping and intrusion of U and bodily intrusion of U were observed during 0.1 mm of retraction and 0.23 mm of intrusion. With the additional intrusion on incisors, canine showed extrusion movement, and higher stresses on periodontal ligaments were shifted from U to canines. Incisors also exhibited different mesial-distal angulation in the three simulations, while posterior teeth all suffered mesial inclination. Incorporating intrusion displacement in clear aligners led to a tendency of lingual root movement during incisor retraction. The complexity of tooth movement should be recognized regarding clear aligner therapy.
Topics: Bicuspid; Biomechanical Phenomena; Dentition; Finite Element Analysis; Humans; Incisor; Maxilla; Orthodontic Appliances, Removable; Periodontal Ligament; Printing, Three-Dimensional; Software; Stress, Mechanical; Tooth Mobility; Tooth Movement Techniques
PubMed: 32576935
DOI: 10.1038/s41598-020-67273-2 -
International Journal of Nanomedicine 2023Dental pulp stem cell-derived exosomes (DPSC-EXO), which have biological characteristics similar to those of metrocytes, have been found to be closely associated with...
Dental Pulp Stem Cell-Derived Exosomes Regulate Anti-Inflammatory and Osteogenesis in Periodontal Ligament Stem Cells and Promote the Repair of Experimental Periodontitis in Rats.
PURPOSE
Dental pulp stem cell-derived exosomes (DPSC-EXO), which have biological characteristics similar to those of metrocytes, have been found to be closely associated with tissue regeneration. Periodontitis is an immune inflammation and tissue destructive disease caused by plaque, resulting in alveolar bone loss and periodontal epithelial destruction. It is not clear whether DPSC-EXO can be used as an effective therapy for periodontal regeneration. The purpose of this study was not only to verify the effect of DPSC-EXO on reducing periodontitis and promoting periodontal tissue regeneration, but also to reveal the possible mechanism.
METHODS
DPSC-EXO was isolated by ultracentrifugation. Then it characterized by transmission electron microscope (TEM), nanoparticle tracking analysis (NTA) and Western Blot. In vitro, periodontal ligament stem cells (PDLSCs) were treated with DPSC-EXO, the abilities of cell proliferation, migration and osteogenic potential were evaluated. Furthermore, we detected the expression of IL-1β, TNF-αand key proteins in the IL-6/JAK2/STAT3 signaling pathway after simulating the inflammatory environment by LPS. In addition, the effect of DPSC-EXO on the polarization phenotype of macrophages was detected. In vivo, the experimental periodontitis in rats was established and treated with DPSC-EXO or PBS. After 4 weeks, the maxillae were collected and detected by micro-CT and histological staining.
RESULTS
DPSC-EXO promoted the proliferation, migration and osteogenesis of PDLSCs in vitro. DPSC-EXO also regulated inflammation by inhibiting the IL-6/JAK2/STAT3 signaling pathway during acute inflammatory stress. In addition, the results showed that DPSC-EXO could polarize macrophages from the M1 phenotype to the M2 phenotype. In vivo, we found that DPSC-EXO could effectively reduce alveolar bone loss and promote the healing of the periodontal epithelium in rats with experimental periodontitis.
CONCLUSION
DPSC-EXO plays an important role in inhibiting periodontitis and promoting tissue regeneration. This study provides a promising acellular therapy for periodontitis.
Topics: Animals; Rats; Periodontal Ligament; Alveolar Bone Loss; Dental Pulp; Exosomes; Interleukin-6; Osteogenesis; Periodontitis; Anti-Inflammatory Agents; Inflammation
PubMed: 37608819
DOI: 10.2147/IJN.S420967 -
Advanced Science (Weinheim,... Oct 2023Periodontium supports teeth in a mechanically stimulated tissue environment, where heterogenous stem/progenitor populations contribute to periodontal homeostasis. In...
Periodontium supports teeth in a mechanically stimulated tissue environment, where heterogenous stem/progenitor populations contribute to periodontal homeostasis. In this study, Leptin receptor+ (Lepr+) cells are identified as a distinct periodontal ligament stem cell (PDLSC) population by single-cell RNA sequencing and lineage tracing. These Lepr+ PDLSCs are located in the peri-vascular niche, possessing multilineage potential and contributing to tissue repair in response to injury. Ablation of Lepr+ PDLSCs disrupts periodontal homeostasis. Hyper-loading and unloading of occlusal forces modulate Lepr+ PDLSCs activation. Piezo1 is demonstrated that mediates the mechanosensing of Lepr+ PDLSCs by conditional Piezo1-deficient mice. Meanwhile, Yoda1, a selective activator of Piezo1, significantly accelerates periodontal tissue growth via the induction of Lepr+ cells. In summary, Lepr marks a unique multipotent PDLSC population in vivo, to contribute toward periodontal homeostasis via Piezo1-mediated mechanosensing.
Topics: Animals; Mice; Receptors, Leptin; Cell Differentiation; Periodontal Ligament; Tooth; Stem Cells; Ion Channels
PubMed: 37553778
DOI: 10.1002/advs.202303291 -
BMC Oral Health Dec 2022The effects of upper-molar distalization using clear aligners in combination with Class II elastics for anchorage reinforcement have not been fully investigated yet. The...
INTRODUCTION
The effects of upper-molar distalization using clear aligners in combination with Class II elastics for anchorage reinforcement have not been fully investigated yet. The objective of this study is to analyze the movement and stress of the whole dentition and further explore guidelines for the selection of traction methods.
METHODS
Three-dimensional (3D) finite element models are established to simulate the sequential molar distalization process, including the initial distalization of the 2 molar (Set I) and the initial distalization of the 1 molar (Set II). Each group set features three models: a control model without Class II elastics (model A), Class II elastics attached to the tooth by buttons (model B), and Class II elastics attached to the aligner by precision cutting (model C). The 3D displacements, proclination angles, periodontal ligament (PDL) hydrostatic stress and alveolar bone von Mises stress in the anterior area are recorded.
RESULTS
In all of the models, the maxillary anterior teeth are labial and mesial proclined, whereas the distal moving molars exhibit distal buccal inclination with an extrusion tendency. With the combination of Class II elastics, the anchorage was effectively reinforced; model C demonstrates superior anchorage reinforcement with lower stress distribution in comparison with model B. The upper canines in model B present an extrusion tendency. Meanwhile, the mandibular dentition in models B and C experience undesired movement tendencies with little discrepancy from each other.
CONCLUSIONS
Class II elastics are generally effective for anchorage reinforcement as the upper-molar distalization is performed with clear aligners. Class II elastics attached to an aligner by precision cutting is a superior alternative for maxillary anchorage control in cases that the proclination of upper incisors and extrusion of upper canines are unwanted.
Topics: Finite Element Analysis; Molar; Incisor; Periodontal Ligament; Orthodontic Appliances, Removable
PubMed: 36456944
DOI: 10.1186/s12903-022-02526-2 -
Journal of Cellular Physiology Aug 2023The periodontal ligament is a crucial tissue that provides support to the periodontium. Situated between the alveolar bone and the tooth root, it consists primarily of... (Review)
Review
The periodontal ligament is a crucial tissue that provides support to the periodontium. Situated between the alveolar bone and the tooth root, it consists primarily of fibroblasts, cementoblasts, osteoblasts, osteoclasts, periodontal ligament stem cells (PDLSCs), and epithelial cell rests of Malassez. Fibroblasts, cementoblasts, osteoblasts, and osteoclasts are functionally differentiated cells, whereas PDLSCs are undifferentiated mesenchymal stem cells. The dynamic development of these cells is intricately linked to periodontal changes and homeostasis. Notably, the regulation of programmed cell death facilitates the clearance of necrotic tissue and plays a pivotal role in immune response. However, it also potentially contributes to the loss of periodontal supporting tissues and root resorption. These findings have significant implications for understanding the occurrence and progression of periodontitis, as well as the mechanisms underlying orthodontic root resorption. Further, the regulation of periodontal ligament cell (PDLC) death is influenced by both systemic and local factors. This comprehensive review focuses on recent studies reporting the mechanisms of PDLC death and related factors.
Topics: Humans; Periodontal Ligament; Root Resorption; Periodontium; Apoptosis; Periodontitis
PubMed: 37566596
DOI: 10.1002/jcp.31091