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Compressive stress in periodontal ligament under orthodontic movements during periodontal breakdown.American Journal of Orthodontics and... Mar 2021This analysis aimed to assess quantitatively and qualitatively the compressive stress (S3) in periodontal ligament in a gradual periodontal breakdown (0-8 mm) under...
INTRODUCTION
This analysis aimed to assess quantitatively and qualitatively the compressive stress (S3) in periodontal ligament in a gradual periodontal breakdown (0-8 mm) under orthodontic movements. Correlations between the applied forces, the level of bone resorption, the decrease of force magnitude, and S3 increase were also conducted.
METHODS
On the basis of cone-beam computed tomography examinations (voxel size, 0.075 mm), nine 3-dimensional models of the second mandibular premolar with intact periodontium were created and then individually subjected to various levels of horizontal bone loss. Orthodontic forces (intrusion: 0.2 N; extrusion, rotation, tipping: 0.6 N; translation: 1.2 N) were applied on the brackets. Finite elements analysis was performed, and S3 stresses were quantitatively and qualitatively determined.
RESULTS
Translation and rotation induced the highest stress apically and cervically, whereas intrusion determined the lowest. Apical stress was lower than cervical stress. In intact periodontium, only intrusion and extrusion exhibited S3 stresses lower (apically and cervically) than maximum hydrostatic pressure (MHP) and maximum tolerable stress (MTS). In reduced periodontium, S3 stress (except for intrusion) exceeded MHP and MTS.
CONCLUSIONS
In reduced periodontium, forces of 0.2 N seems safe to be used. Forces of 0.6-1.2 N may produce stresses exceeding both MTS and MHP, endangering the periodontium. S3 failure criterion (despite its widely use) seems not to be adequate for accurate quantitative results when evaluating the stress in the periodontal ligament while remaining adequate for qualitative results. An overall correlation between the applied force, S3 increase, and periodontal breakdown applicable to all 5 movements could not be established-this was possible only for sole movements.
Topics: Computer Simulation; Cone-Beam Computed Tomography; Finite Element Analysis; Humans; Models, Biological; Periodontal Ligament; Pressure; Stress, Mechanical; Tooth Movement Techniques
PubMed: 33487500
DOI: 10.1016/j.ajodo.2020.10.021 -
Acta Biomaterialia Sep 2022Periodontal regeneration is characterized by the attachment of oblique periodontal ligament fibres on the tooth root surface. To facilitate periodontal ligament...
Periodontal regeneration is characterized by the attachment of oblique periodontal ligament fibres on the tooth root surface. To facilitate periodontal ligament attachment, a fibre-guiding tissue engineered biphasic construct was manufactured by melt electrowriting (MEW) for influencing reproducible cell guidance and tissue orientation. The biphasic scaffold contained fibre-guiding features in the periodontal ligament component comprising of 100 µm spaced channels (100CH), a pore size gradient in the bone component and maintained a highly porous and fully interconnected interface between the compartments. The efficacy of the fibre-guiding channels was assessed in an ectopic periodontal attachment model in immunocompromised rats. This demonstrated an unprecedented and systematic tissue alignment perpendicular to the dentin in the 100CH group, resulting in the close mimicry of native periodontal ligament architecture. In addition, the histology revealed high levels of tissue integration between the two compartments as observed by the perpendicular collagen attachment on the dentin surface, which also extended and infiltrated the scaffold's bone compartment. In conclusion, the 100 µm fibre-guiding scaffold induced a systematic tissue orientation at the dentin-ligament interface, resembling the native periodontium and thus resulting in enhanced alignment mimicking periodontal ligament regeneration. STATEMENT OF SIGNIFICANCE: Periodontitis is a prevalent inflammatory disease affecting a large portion of the adult population and leading to the destruction of the tooth-supporting structures (alveolar bone, periodontal ligament, and cementum). Current surgical treatments are unpredictable and generally result in repair rather than functional regeneration. A key feature of functional regeneration is the re-insertion of the oblique or perpendicularly orientated periodontal ligament fibre in both the alveolar bone and root surface. This study demonstrates that a highly porous scaffold featuring 100 µm width channels manufactured by the stacking of melt electrospun fibres, induced perpendicular alignment and attachment of the neo-ligament onto a dentine surface. The fibre guiding micro-architecture may pave the way for enhanced and more functional regeneration of the periodontium.
Topics: Animals; Collagen; Dental Cementum; Ligaments; Periodontal Ligament; Periodontium; Rats; Tissue Engineering
PubMed: 35853598
DOI: 10.1016/j.actbio.2022.07.023 -
American Journal of Orthodontics and... Feb 2022This research aimed to assess qualitatively and quantitatively the overall stress in the periodontal ligament during gradual periodontal breakdown (0-8 mm) under...
INTRODUCTION
This research aimed to assess qualitatively and quantitatively the overall stress in the periodontal ligament during gradual periodontal breakdown (0-8 mm) under orthodontic movements. Correlations between the applied forces, the level of bone loss, the decrease of force magnitude, and the increase of stress were also assessed.
METHODS
On the basis of cone-beam computed tomography examinations (voxel size, 0.075 mm), nine 3-dimensional models of a mandibular second premolar with intact periodontium were created and then individually subjected to various levels of horizontal bone loss. Orthodontic forces (intrusion at 0.2 N; extrusion, rotation, and tipping at 0.6 N; translation at 1.2 N) were applied on the brackets. Finite elements analysis was performed, and von Mises (VM) stresses were quantitatively and qualitatively determined.
RESULTS
Rotation and translation induced the highest stress apically and cervically, whereas intrusion determined the lowest. Apical stress was lower than cervical stress. In intact periodontium, VM stress was under maximum hydrostatic pressure (MHP) and maximum tolerable stress (MTS). In reduced periodontium, VM stress was lower apically than MHP, whereas cervically, the rotation, translation, and tipping exceeded MHP.
CONCLUSIONS
A force of 1.2 N seemed safe to be used in the intact periodontium. Forces higher than 0.6 N could produce stresses exceeding MHP and MTS endangering the reduced periodontium. VM stress failure criterion (despite its limited use) seemed to be more adequate for accurate quantitative results. An overall correlation between the applied force, VM stress increase, and periodontal breakdown applicable to all 5 movements could not be established. This was possible only for individual movements.
Topics: Computer Simulation; Finite Element Analysis; Humans; Models, Biological; Periodontal Ligament; Stress, Mechanical; Tooth Movement Techniques
PubMed: 34563425
DOI: 10.1016/j.ajodo.2021.06.014 -
Journal of Dental Research Nov 2022Successful periodontal repair and regeneration requires the coordinated responses from soft and hard tissues as well as the soft tissue-to-bone interfaces. Inspired by...
Successful periodontal repair and regeneration requires the coordinated responses from soft and hard tissues as well as the soft tissue-to-bone interfaces. Inspired by the hierarchical structure of native periodontal tissues, tissue engineering technology provides unique opportunities to coordinate multiple cell types into scaffolds that mimic the natural periodontal structure in vitro. In this study, we designed and fabricated highly ordered multicompartmental scaffolds by melt electrowriting, an advanced 3-dimensional (3D) printing technique. This strategy attempted to mimic the characteristic periodontal microenvironment through multicompartmental constructs comprising 3 tissue-specific regions: 1) a bone compartment with dense mesh structure, 2) a ligament compartment mimicking the highly aligned periodontal ligaments (PDLs), and 3) a transition region that bridges the bone and ligament, a critical feature that differentiates this system from mono- or bicompartmental alternatives. The multicompartmental constructs successfully achieved coordinated proliferation and differentiation of multiple cell types in vitro within short time, including both ligamentous- and bone-derived cells. Long-term 3D coculture of primary human osteoblasts and PDL fibroblasts led to a mineral gradient from calcified to uncalcified regions with PDL-like insertions within the transition region, an effect that is challenging to achieve with mono- or bicompartmental platforms. This process effectively recapitulates the key feature of interfacial tissues in periodontium. Collectively, this tissue-engineered approach offers a fundament for engineering periodontal tissue constructs with characteristic 3D microenvironments similar to native tissues. This multicompartmental 3D printing approach is also highly compatible with the design of next-generation scaffolds, with both highly adjustable compartmentalization properties and patient-specific shapes, for multitissue engineering in complex periodontal defects.
Topics: Humans; Tissue Engineering; Tissue Scaffolds; Periodontium; Printing, Three-Dimensional; Periodontal Ligament
PubMed: 35689382
DOI: 10.1177/00220345221099823 -
Molecules (Basel, Switzerland) Oct 2020The mineralized tissues (alveolar bone and cementum) are the major components of periodontal tissues and play a critical role to anchor periodontal ligament (PDL) to... (Review)
Review
The mineralized tissues (alveolar bone and cementum) are the major components of periodontal tissues and play a critical role to anchor periodontal ligament (PDL) to tooth-root surfaces. The integrated multiple tissues could generate biological or physiological responses to transmitted biomechanical forces by mastication or occlusion. However, due to periodontitis or traumatic injuries, affect destruction or progressive damage of periodontal hard tissues including PDL could be affected and consequently lead to tooth loss. Conventional tissue engineering approaches have been developed to regenerate or repair periodontium but, engineered periodontal tissue formation is still challenging because there are still limitations to control spatial compartmentalization for individual tissues and provide optimal 3D constructs for tooth-supporting tissue regeneration and maturation. Here, we present the recently developed strategies to induce osteogenesis and cementogenesis by the fabrication of 3D architectures or the chemical modifications of biopolymeric materials. These techniques in tooth-supporting hard tissue engineering are highly promising to promote the periodontal regeneration and advance the interfacial tissue formation for tissue integrations of PDL fibrous connective tissue bundles (alveolar bone-to-PDL or PDL-to-cementum) for functioning restorations of the periodontal complex.
Topics: Animals; Biopolymers; Humans; Osteogenesis; Periodontal Ligament; Periodontitis; Periodontium; Regeneration; Tissue Engineering; Tooth; Wound Healing
PubMed: 33086674
DOI: 10.3390/molecules25204802 -
Journal of Periodontal Research Aug 2023Teeth are subject to a variety of mechanical forces and vectors. The periodontal ligament (PDL), fibrous tissue that connects the cementum of the tooth to the bony... (Review)
Review
Teeth are subject to a variety of mechanical forces and vectors. The periodontal ligament (PDL), fibrous tissue that connects the cementum of the tooth to the bony socket, plays a decisive role in transmitting force to alveolar bone via Sharpey fibers, transforming and converting these forces into biological signals. This interaction effects significant osteoblastic and osteoclastic responses via autocrine proliferative and paracrine responses. Recent discoveries of receptors for temperature and touch by the Nobel laureates David Julius and Ardem Patapoutian, respectively have a profound impact on orthodontics. Transient receptor vanilloid channel 1 (TRPV1), initially described as a receptor for temperature, has been proposed to participate in the sensing of force. TRPV4, another ion channel receptor, perceives tensile forces as well as thermal and chemical stimuli. Piezo1 and 2, the classic receptors for touch, in addition to the aforementioned receptors, have similarly been described on PDL-derived cells. In this text, we review the role of the temperature-sensitive ion channels and mechanosensitive ion channels on their biological function and influence in orthodontic treatment.
Topics: Periodontal Ligament; Temperature; Ion Channels; Dental Cementum; Mechanotransduction, Cellular
PubMed: 37291724
DOI: 10.1111/jre.13137 -
Zhonghua Kou Qiang Yi Xue Za Zhi =... Aug 2020Tooth loss caused by trauma, periodontitis or inherited disorders severely affects human physical and mental health. As an essential part of the tooth, tooth root is... (Review)
Review
Tooth loss caused by trauma, periodontitis or inherited disorders severely affects human physical and mental health. As an essential part of the tooth, tooth root is connected to periodontal tissues to maintain the tooth in the alveolar socket. To figure out the molecular mechanisms regulating tooth root development will contribute to the discovery of new approaches in tooth root regeneration. The development of tooth root is a complicated process involving communication between the epithelial and mesenchymal tissues and the regulation of multiple signaling pathways. The present article reviewed the research progress of the signaling pathways in tooth root development.
Topics: Humans; Odontogenesis; Periodontal Ligament; Periodontium; Tooth; Tooth Root
PubMed: 32842352
DOI: 10.3760/cma.j.cn112144-20191226-00466 -
Journal of Advanced Research Jun 2024Periodontal regeneration, specifically the restoration of the cementum-periodontal ligament (PDL)-alveolar bone complex, remains a formidable challenge in the field of...
INTRODUCTION
Periodontal regeneration, specifically the restoration of the cementum-periodontal ligament (PDL)-alveolar bone complex, remains a formidable challenge in the field of regenerative dentistry. In light of periodontal development, harnessing the multi-tissue developmental capabilities of periodontal ligament cells (PDLCs) and reinitiating the periodontal developmental process hold great promise as an effective strategy to foster the regeneration of the periodontal complex.
OBJECTIVES
This study aims to delve into the potential effects of the macrophage-mediated immune microenvironment on the "developmental engineering" regeneration strategy and its underlying molecular mechanisms.
METHODS
In this study, we conducted a comprehensive examination of the periodontium developmental process in the rat mandibular first molar using histological staining. Through the induction of diverse immune microenvironments in macrophages, we evaluated their potential effects on periodontal re-development events using a cytokine array. Additionally, we investigated PDLC-mediated periodontal re-development events under these distinct immune microenvironments through transcriptome sequencing and relevant functional assays. Furthermore, the underlying molecular mechanism was also performed.
RESULTS
The activation of development-related functions in PDLCs proved challenging due to their declined activity. However, our findings suggest that modulating the macrophage immune response can effectively regulate PDLCs-mediated periodontium development-related events. The M1 type macrophage immune microenvironment was found to promote PDLC activities associated with epithelial-mesenchymal transition, fiber degradation, osteoclastogenesis, and inflammation through the Wnt, IL-17, and TNF signaling pathways. Conversely, the M2 type macrophage immune microenvironment demonstrated superiority in inducing epithelium induction, fibers formation, and mineralization performance of PDLCs by upregulating the TGFβ and PI3K-Akt signaling pathway.
CONCLUSION
The results of this study could provide some favorable theoretical bases for applying periodontal development engineering strategy in resolving the difficulties in periodontal multi-tissue regeneration.
Topics: Periodontal Ligament; Animals; Macrophages; Rats; Male; Regeneration; Cellular Microenvironment; Cells, Cultured; Rats, Sprague-Dawley; Cell Differentiation; Cytokines; Signal Transduction; Molar
PubMed: 37597747
DOI: 10.1016/j.jare.2023.08.009 -
Journal of Clinical Periodontology Apr 2016
Topics: Dental Cementum; Periodontal Ligament; Periodontium
PubMed: 26878344
DOI: 10.1111/jcpe.12532 -
Current Stem Cell Research & Therapy 2019Periodontitis is an inflammatory disease that can result in destruction of the tooth attachment apparatus. Therefore, periodontal tissue regeneration is currently an... (Review)
Review
BACKGROUND
Periodontitis is an inflammatory disease that can result in destruction of the tooth attachment apparatus. Therefore, periodontal tissue regeneration is currently an important focus of research in the field. Approaches using stem cells and reprogrammed cells, such as induced pluripotent stem cells (iPSCs) or trans-differentiated cells, represent the cutting edge in periodontal regeneration, and have led to many trials for their clinical application. Objectives and Results: In this review, we consider all available stem cell sources, methods to obtain the cells, their capability to differentiate into the desired cells, and the extent of their utilization in periodontal regeneration. In addition, we introduce the new concepts of using iPSCs and transdifferentiated cells for periodontal regeneration. Finally, we discuss the promise of tissue engineering for improving cell therapy outcomes for periodontal regeneration.
CONCLUSIONS
Despite their limitations, iPSCs and trans-differentiated cells may be promising cell sources for periodontal tissue regeneration. Further collaborative investigation is required for the effective and safe application of these cells in combination with tissue engineering elements, like scaffolds and biosignals.
Topics: Cell- and Tissue-Based Therapy; Cellular Reprogramming; Cementogenesis; Dental Pulp; Dental Sac; Epithelial Attachment; Gingiva; Guided Tissue Regeneration, Periodontal; Humans; Induced Pluripotent Stem Cells; Periodontal Ligament; Periodontitis; Periodontium; Regeneration; Regenerative Medicine; Tissue Engineering; Tissue Scaffolds; Tooth, Deciduous
PubMed: 30112999
DOI: 10.2174/1574888X13666180816113456