Complex crown-root fractures in the esthetic zone refer to a type of dental trauma occurring in the anterior region, characterized by concurrent fractures involving both the crown and the root, with associated pulp exposure and periodontal tissue injury. These injuries consistently exhibit critical anatomical features, including a fixed palatal fracture location below the alveolar crest, compromised residual tooth structure, and frequent encroachment of the biological width. To predict treatment outcomes, a risk assessment framework based on the restoration-tooth-periodontium interface was developed. Resistance risk was evaluated by assessing the type of residual dentin ferrule and the length of the root within the alveolar bone, while periodontal risk was assessed according to gingival phenotype and alveolar bone morphology. Based on these risk dimensions and the principles of aesthetics, stability, and minimally invasive treatment, a diagnostic classification system was established to categorize fractures into three types: favorable, intervention and high-risk. Type-specific management strategies were proposed: for favorable cases, crown lengthening combined with deep margin elevation to reduce periodontal risk is recommended; for intervention cases, orthodontic extrusion or surgical extrusion is applied to simultaneously address both ferrule deficiency and biological width violation; for high-risk cases, extraction followed by implant restoration is advised due to limited root preservation value. The presented classification enables clinicians to adopt a scientific and structured approach to treatment planning for these complex crown-root fractures in the aesthetic zone.
Humans ; Tooth Fractures/therapy* ; Tooth Root/injuries* ; Risk Assessment ; Tooth Crown/injuries* ; Periodontium ; Esthetics, Dental ; Dental Restoration, Permanent/methods*

Periodontal bone defects, primarily caused by periodontitis, are highly prevalent in clinical settings and manifest as bone fenestration, dehiscence, or attachment loss, presenting a significant challenge to oral health. In regenerative medicine, harnessing developmental principles for tissue repair offers promising therapeutic potential. Of particular interest is the condensation of progenitor cells, an essential event in organogenesis that has inspired clinically effective cell aggregation approaches in dental regeneration. However, the precise cellular coordination mechanisms during condensation and regeneration remain elusive. Here, taking the tooth as a model organ, we employed single-cell RNA sequencing to dissect the cellular composition and heterogeneity of human dental follicle and dental papilla, revealing a distinct Platelet-derived growth factor receptor alpha (PDGFRA) mesenchymal stem/stromal cell (MSC) population with remarkable odontogenic potential. Interestingly, a reciprocal paracrine interaction between PDGFRA⁺ dental follicle stem cells (DFSCs) and CD31⁺ Endomucin⁺ endothelial cells (ECs) was mediated by Vascular endothelial growth factor A (VEGFA) and Platelet-derived growth factor subunit BB (PDGFBB). This crosstalk not only maintains the functionality of PDGFRA⁺ DFSCs but also drives specialized angiogenesis. In vivo periodontal bone regeneration experiments further reveal that communication between PDGFRA⁺ DFSC aggregates and recipient ECs is essential for effective angiogenic-osteogenic coupling and rapid tissue repair. Collectively, our results unravel the importance of MSC-EC crosstalk mediated by the VEGFA and PDGFBB-PDGFRA reciprocal signaling in orchestrating angiogenesis and osteogenesis. These findings not only establish a framework for deciphering and promoting periodontal bone regeneration in potential clinical applications but also offer insights for future therapeutic strategies in dental or broader regenerative medicine.
Receptor, Platelet-Derived Growth Factor alpha/metabolism* ; Humans ; Neovascularization, Physiologic/physiology* ; Dental Sac/cytology* ; Single-Cell Analysis ; Transcriptome ; Mesenchymal Stem Cells/metabolism* ; Bone Regeneration ; Animals ; Dental Papilla/cytology* ; Periodontium/physiology* ; Stem Cells/metabolism* ; Regeneration ; Angiogenesis

Periodontal diseases are inflammatory diseases caused by oral pathogens around the periodontal supporting tissues, leading to systemic and chronic inflammatory conditions. The continuous chronic systemic inflammation may be a trigger of neuroinflammation, which is the prominent feature of a variety of neurological disorders. It implies that there may be a causal link between periodontal diseases and neurological disorders. This article presents epidemiological and biological evidences that periodontal diseases can induce or exacerbate neurological disorders, including Alzheimer's disease, Parkinson's disease, multiple sclerosis and major depressive disorder, and analyzes the possible mechanisms. The importance of maintaining oral health as well as preventing and treating periodontal diseases are emphasized. At the same time, this may provide novel approaches to study the relationship between periodontal diseases and neurological disorders in the prevention and treatment strategies of neurological disorders.
Alzheimer Disease ; Depressive Disorder, Major/complications* ; Humans ; Inflammation/complications* ; Periodontal Diseases/complications* ; Periodontium

Although mesenchymal stem cell-derived exosomes (MSC-exos) have been shown to have therapeutic effects in experimental periodontitis, their drawbacks, such as low yield and limited efficacy, have hampered their clinical application. These drawbacks can be largely reduced by replacing the traditional 2D culture system with a 3D system. However, the potential function of MSC-exos produced by 3D culture (3D-exos) in periodontitis remains elusive. This study showed that compared with MSC-exos generated via 2D culture (2D-exos), 3D-exos showed enhanced anti-inflammatory effects in a ligature-induced model of periodontitis by restoring the reactive T helper 17 (Th17) cell/Treg balance in inflamed periodontal tissues. Mechanistically, 3D-exos exhibited greater enrichment of miR-1246, which can suppress the expression of Nfat5, a key factor that mediates Th17 cell polarization in a sequence-dependent manner. Furthermore, we found that recovery of the Th17 cell/Treg balance in the inflamed periodontium by the local injection of 3D-exos attenuated experimental colitis. Our study not only showed that by restoring the Th17 cell/Treg balance through the miR-1246/Nfat5 axis, the 3D culture system improved the function of MSC-exos in the treatment of periodontitis, but also it provided a basis for treating inflammatory bowel disease (IBD) by restoring immune responses in the inflamed periodontium.
Colitis ; Exosomes ; Humans ; Periodontitis/therapy* ; Periodontium ; T-Lymphocytes, Regulatory ; Th17 Cells

Eosinophilic granuloma, a rare disease, has various clinical manifestations and no specific X-rays features and is thus easily misdiagnosed. This paper reports a case of multifocal eosinophilic granuloma of jaw with long-term follow-up. The patient initially presented with periodontal tissue destruction.The diagnosis, treatment and prognosis of multifocal eosinophilic granuloma of jaw were discussed in combination with the literature to alert this disease in clinical practice.
Diagnosis, Differential ; Eosinophilic Granuloma/diagnostic imaging* ; Humans ; Jaw ; Periodontium ; Radiography

OBJECTIVES: The safety of root canal filling with 200 °C hot gutta-percha was investigated to study the effect of continuous wave technique combined with high-temperature injectable gutta-percha condensation technique on the surface temperature of periodontal tissue. METHODS: CT technique and Mimics, Geomagic, and Solidworks software were utilized to build the entity models of alveolar bone, dentin and root canal, periodontal ligament, and blood flow, respectively, which were then assembled in Solidworks into a finite element model of tooth with blood flow. By utilizing ABAQUS collaborative simulation platform, fluid-structure coupling was analyzed on the whole process of root canal filling. Consequently, the surface temperature of the periodontal tissue was obtained. RESULTS: In the absence of blood flow, the temperature of the periodontal ligament surface reached 50.048 ℃ during root canal filling with 200 ℃ gutta-percha. Considering blood flow, the temperature of periodontal ligament surface was 39.570 ℃. CONCLUSIONS The temperature of the periodontal ligament surface increased when the continuous wave root canal was filled with 200 ℃ gutta-percha, and the periodontal tissue was not damaged.
Dental Pulp Cavity ; Finite Element Analysis ; Gutta-Percha ; Hot Temperature ; Humans ; Periodontium ; Root Canal Filling Materials ; Root Canal Obturation ; Temperature

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.
Humans ; Osteoblasts ; Osteoclasts ; Periodontal Ligament ; Periodontium ; Root Resorption ; Tooth Movement Techniques

OBJECTIVE: Calprotectin, the heterdimer of S100A8 and S100A9, is the major cytoplasmic protein of neutrophils, which is also expressed or induced in gingival epithelial cells, activated mononuclear macrophages and vascular endothelial cells. Calprotectin is intimately associated with the initiation and progression of periodontitis, but the in vivo expression patterns of calprotectin in healthy and inflamed periodontal tissue are not fully understood. To observe the expression, distribution and cellular localization of calprotectin in the samples of healthy periodontal tissues and experimental periodontitis tissues of Beagles and to explore their relationship with periodontal inflammation and possible effect. METHODS: Experimental periodontitis model was established by ligation around the mandibular second molar of the Beagle dogs, while the contralateral teeth were healthy controls. Induction duration was 12 weeks, before the dogs were executed. Tissue specimens were demineralized and serial sections were made conventionally. The in vivo expression of calprotectin in the healthy and inflamed periodontal tissues were examined by immunohistochemistry. The in vitro expression of calprotectin in human primary gingival fibroblasts (GFs) and periodontal ligament (PDL) cells were detected by immunocytochemistry. RESULTS: Immunohistochemistry analysis indicated that calprotectin was expressed in gingival epithelial cells and infiltrated neutrophils in the healthy periodontium within the gingival epithelium, S100A8/A9 was most strongly expressed in the junctional epithelium, followed by surface epithelium, and least expressed in the sulcular epithelium. The S100A8/A9 expression levels were sharply defined at the junction between the junctional epithelium and the sulcular epithelium. In periodontal inflammatory lesions, the expression level of calprotectin in sulcular epithelium and junctional epithelium was up-regulated than that in the healthy gingival epithelium. Calprotectin was inducibly expressed in fibroblast-like cells in gingival connective tissue and periodontal ligament tissue, microvascular endothelial cells (ECs) and bone marrow fibroblasts under inflammatory conditions. Additionally, the expression of calprotectin in primary human GFs and PDL cells was confirmed by immunnocytochemistry staining. CONCLUSION Constitutively expressed in neutrophils and gingival epithelial cells, and calprotectin might maintain the homeostasis and integrity of periodontium. Inflammation-induced expression of calprotectin in GFs, PDL cells, microvascular ECs and bone marrow fibroblasts might process anti-microbial function and promote leukocytes transmigration to defend the host against the microorganisms.
Animals ; Dogs ; Endothelial Cells ; Epithelial Attachment ; Gingiva ; Humans ; Leukocyte L1 Antigen Complex ; Periodontium

Periodontal procedures require adequate anesthesia not only to ensure the patient's comfort but also to enhance the operator's performance and minimize chair time. In the maxilla, anesthesia is often achieved using highly traumatic nerve blocks, apart from multiple local infiltrations through the buccal vestibule. In recent years, anterior middle superior alveolar (AMSA) field block has been claimed to be a less traumatic alternative to several of these conventional injections, and it has many other advantages. This critical review of the existing literature aimed to discuss the rationale, mechanism, effectiveness, extent, and duration of AMSA injections for periodontal surgical and non-surgical procedures in the maxilla. It also focused on future prospects, particularly in relation to computer-controlled local anesthetic delivery systems, which aim to achieve the goal of pain-free anesthesia. A literature search of different databases was performed to retrieve relevant articles related to AMSA injections. After analyzing the existing data, it can be concluded that this anesthetic technique may be used as a predictable method of effective palatal anesthesia with adequate duration for different periodontal procedures. It has additional advantages of being less traumatic, requiring lesser amounts of local anesthetics and vasoconstrictors, as well as achieving good hemostasis. However, its effect on the buccal periodontium appears highly unpredictable.
Amsacrine ; Anesthesia ; Anesthetics, Local ; Hemostasis ; Maxilla ; Methods ; Nerve Block ; Palate ; Periodontal Debridement ; Periodontium ; Vasoconstrictor Agents

Periodontitis is a chronic inflammatory disease of periodontal tissues initiated by oral biofilm. Cellular autophagy is an effective weapon against bacterial infection. Recent studies have shown that autophagy not only promotes the removal of bacteria and toxins from infected cells, but also helps to suppress the inflammatory response to maintain the homeostasis of intracellular environment, which is closely related to the development of periodontitis. Here, we reviewed the relationship between autophagy and periodontitis from three aspects: the interactions between autophagy and periodontal pathogen infection, the regulation of autophagy and immune inflammatory responses, and the relationship between autophagy and alveolar bone metabolism. We aim to provide ideas for further study on the mechanisms of autophagy and periodontitis, and ultimately contribute to a better prevention and treatment of periodontitis.
Autophagy ; Bacteria ; Biofilms ; Humans ; Periodontitis ; Periodontium