Adenoid hypertrophy is one of the most common causes of upper airway obstruction in children, often presenting with nasal congestion as the initial symptom and accompanied by a series of related manifestations. Due to impaired nasal ventilation, affected children are forced into compensatory mouth breathing. This altered breathing pattern modifies the upper airway fluid environment, leading to abnormal changes in airflow velocity, pressure distribution, and flow patterns. Prolonged mouth breathing disrupts the dynamic equilibrium of perioral musculature, thereby interfering with normal maxillofacial growth and development and contributing to the occurrence of malocclusion. Upper airway fluid mechanics, developed through the integration of computational fluid dynamics (CFD) technology and medical imaging, serves as a quantitative analytical tool capable of precisely characterizing airflow velocity, pressure distribution, and flow patterns within anatomically complex structures such as the nasal cavity and pharynx. By leveraging multidimensional fluid mechanical parameters, this approach can accurately depict the flow field characteristics of the upper airway in patients with adenoid hypertrophy, clearly illustrating the relationship between airway anatomy and ventilatory function, and providing objective quantitative evidence for disease assessment. In clinical practice, CFD enables the evaluation of how different interventions improve airway ventilation, allowing scientific prediction and objective assessment of therapeutic outcomes. Nevertheless, several critical challenges remain, including the lack of standardized protocols for upper airway modeling and boundary condition definition, insufficient understanding of the dynamic relationship between fluid mechanical parameters and the progression of malocclusion severity, and the predominance of cross-sectional study designs with limited longitudinal data on pre- and post-intervention flow field changes, which restricts the translation of simulation results into actionable clinical indicators. In the future, with the establishment of standardized simulation workflows and the conduct of large-scale prospective cohort studies, upper airway fluid mechanics is expected to integrate with artificial intelligence and multimodal imaging technologies to develop intelligent decision-support systems, thereby advancing the scientific rigor and personalization of diagnosis and treatment for adenoid hypertrophy and associated malocclusion.
Mandibular condylar fractures are common injuries in oral and maxillofacial surgery. The unique anatomical structure and mechanical environment of the condyle render its fracture healing process distinct from that of long bones. Parathyroid hormone (PTH) and its active fragment PTH(1-34) (such as the drug teriparatide) are among the few clinically available agents with bone-anabolic properties, and have shown promise in fracture repair. However, the anatomical and mechanical discrepancies between the condyle and long bones raise doubts as to whether the efficacy of PTH observed in long bones can be directly extrapolated to condylar fractures. Elucidating how mechanical loading modulates the bone remodeling effects of PTH within the specific mechanical environment of the mandibular condyle thus constitutes a critical entry point for addressing this question. This review summarizes recent advances regarding how mechanical loading influences PTH-promoted healing of mandibular condylar fractures from three perspectives: the mechanical sensitivity of condylar fracture healing, the molecular mechanisms by which PTH regulates bone remodeling, and the synergy between mechanical and pharmacological interventions, with the aim of clarifying the existing molecular evidence for mechanical-PTH synergy derived from long-bone and in vitro models, and critically evaluating the feasibility and limitations of extrapolating these findings to condylar fractures. Evidence from long-bone fracture models and in vitro mechanical loading systems indicates that mechanical loading modulates the direction of PTH-mediated bone remodeling through the receptor activator of the nuclear factor-κB ligand (RANKL)/osteoprotegerin (OPG) axis and the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/glycogen synthase kinase-3β (GSK3β)/nuclear factor of the activated T-cells c1 (NFATc1) pathway, an effect that exhibits marked intensity- and time-dependent characteristics. Nevertheless, critical challenges remain in this field, including the standardization of quantitative mechanical loading parameters, the accumulation of direct evidence from condyle-specific fracture models, and the in-depth elucidation of the regulatory mechanisms governing mechanical-drug synergy. Future research should integrate finite element analysis, standardized mechanical loading techniques, and single-cell omics to establish a quantitative relationship between mechanical parameters, cellular responses, and PTH effects, thereby providing a theoretical basis for optimizing postoperative masticatory load management and PTH administration strategies in condylar fractures.
Objective To explore new therapeutic strategies for periodontitis, this study prepared extracellular vesicles (EVs) derived from human umbilical cord mesenchymal stem cells (hUC-MSCs) loaded with saikosaponin D (SSD) and evaluated their efficacy in a mouse model of periodontitis. Methods This study was approved by the Medical Ethics Committee and the Laboratory Animal Ethics Committee of the unit. hUC-MSCs at logarithmic growth phase were seeded into 96 well plates and then treated with various concentrations of SSD for 24 hours. The CCK-8 assay was used to determine the SSD concentration that preserves hUC-MSC viability. Flow cytometry (FCM) assessed SSD-induced apoptosis in hUC-MSCs and determined drug loading and loading efficiency. Nanoparticle tracking analysis (NTA) and transmission electron microscopy (TEM) characterized the morphology and size of hUC-MSCs-EVs and hUC-MSCs-SSD-EVs. C57BL/6J mice were divided into five groups with six mice per group: control group, periodontitis model group (PD), PD+SSD group (2 mg/kg), PD+hUC-MSCs-EVs group (10 μg/μL) and PD+hUC-MSCs-SSD-EVs group (10 μg/μL). Administration was performed 3 times a week for 4 consecutive weeks. Micro-CT and hematoxylin-eosin (HE) staining evaluated alveolar bone resorption in periodontal tissues of a mouse model of periodontitis. RT-qPCR measured inflammatory cytokine expression in periodontal tissues of a mouse model of periodontitis. Immunofluorescence analyzed macrophage M1/M2 polarization and runt-related transcription factor 2 (RUNX2) protein expression in periodontal tissues of a mouse model of periodontitis. Results The CCK-8 assay showed that 10 μmol/L SSD had little effect on hUC-MSCs viability (P>0.05). FCM confirmed the successful loading of SSD into EVs with a loading efficiency of 11.40%. TEM and NTA revealed that hUC-MSCs-SSD-EVs presented round or oval membranous structures with diameters ranging from 200 to 300 nm. Micro CT and HE staining showed that, compared with the PD group, the distance from cementoenamel junction to alveolar bone crest (CEJ-ABC) was markedly shortened (P<0.01）.The alveolar bone of periodontitis‑model bone volume fraction (BV/TV) and trabecular number (Tb.N) were significantly elevated in the PD+hUC-MSCs-SSD-EVs group (P<0.01). RT-qPCR and IF results showed that hUC-MSCs-SSD-EVs in periodontal tissues markedly downregulated the expression of pro-inflammatory cytokines including interleukin-1β, interleukin-6, tumor necrosis factor-α, interleukin-12 and interleukin-22 (P<0.01), upregulated the expression of the anti-inflammatory factor interleukin-10 (P<0.01), promoted the polarization of macrophages from the M1 phenotype to the M2 phenotype, and elevated the protein expression level of RUNX2 (P<0.01). Conclusion hUC-MSC-SSD-EVs effectively alleviated inflammatory responses in a mouse model of maxillary periodontitis and reduced alveolar bone loss, providing a new idea for the treatment of periodontitis.
Objective The present study aimed to evaluate the clinical efficacy of hydraulic sinus floor elevation for the treatment of insufficient bone height in the posterior maxilla through a systematic review and Meta-analysis, so as to provide evidence for clinical practice. Methods Databases including PubMed, Embase, Cochrane Library, and Clinical Trials.gov were searched up to May 2025. Randomized controlled trials, non-randomized controlled trials, cohort studies, cross-sectional studies, and case-control studies that involved patients receiving hydraulic sinus floor elevation with simultaneous or delayed implant placement were included. Exclusion criteria comprised in vitro studies, animal experiments, narrative reviews, unpublished data, commentaries or expert opinions, studies with unclear sample sizes, and publications without full-text access or unavailable outcome data. Three investigators independently performed literature screening and quality assessment. A single-arm Meta-analysis was conducted using Stata 18.0 for studies meeting the inclusion criteria. The outcome measures were the incidence of sinus membrane perforation, implant survival rate, and endo-sinus bone gain. The Cochrane Risk of Bias 2 (RoB2) tool and the Joanna Briggs Institute (JBI) critical appraisal checklist were used to assess the methodological quality of randomized controlled trials and non-randomized controlled trials, respectively. The overall certainty of evidence was assessed using the GRADE（Grading of Recommendations Assessment, Development and Evaluation）system. Results Nineteen studies with 982 patients, 1 151 elevated sites, and 1 263 implants were finally included. The Meta-analysis showed that the intraoperative sinus membrane perforation rate of hydraulic sinus floor elevation was 2.0% [ES = 0.02, 95% CI (0.00, 0.04)] (18 studies, 1 061 sites); the implant survival rate was 99.0% [ES = 0.99, 95% CI (0.97, 1.00)] (17 studies, 1 253 implants); and the mean vertical bone gain was 7.80 mm. For this outcome, heterogeneity among studies was extremely high (I2 = 98.6%), thus only descriptive analysis was performed. Egger's test revealed no significant publication bias for the three outcomes. GRADE grading indicated very low certainty of evidence for mucosal perforation, implant survival rate, and endo sinus bone gain. Conclusion Current preliminary evidence suggests that hydraulic sinus lift may be a safe minimally invasive technique, but the evidence is very low, and more high quality, long term follow up randomized controlled clinical trials are still needed for further verification.
Objective To investigate the bactericidal efficacy and impact on oral mixed biofilm microbial structure of commonly used clinical root canal irrigants under dynamic oxygen conditions, and to provide experimental evidence for clinical root canal irrigant selection. Methods This study has been reviewed and approved by the Medical Ethics Committee, and written informed consent has been obtained from all of the participants. Two healthy oral volunteers from Beijing Stomatological Hospital, Capital Medical University were selected, and subgingival and supragingival plaque from their mandibular premolars and molars were extracted to construct an oral mixed microbial biofilm model. The plaque was cultivated on hydroxyapatite slices for 1 week (anaerobic conditions for 3 days + aerobic conditions for 4 days) to construct a young oral mixed bacterial biofilm model, and cultivated for 3 weeks (anaerobic conditions for 3 days + aerobic conditions for 18 days) to construct a mature oral mixed bacterial biofilm model. Three root canal irrigating solutions were used: sterile water (control), 2% chlorhexidine (CHX), and 1% sodium hypochlorite (NaOCl). The bacterial biofilms were treated for 1 week and 3 weeks, respectively, and the overall bactericidal rate was assessed using live/dead bacterial staining and laser confocal microscopy. Concurrently, high-throughput 16S rRNA sequencing was performed to analyze the microbial community structure and to evaluate the antibacterial effects of irrigation solution, on common dominant pathogens. Results The proportion of dead bacteria in the biofilm treated with three types of root canal irrigation drugs at 1 week and 3 weeks, from high to low, were as follows: 1% NaOCl >2% CHX >control group (P < 0.001). The bactericidal rate of 1% NaOCl on mature biofilms at 3 weeks was significantly lower than that of light biofilms at 1 year (P < 0.001). High-throughput sequencing revealed minimal effects of 2% CHX and 1% NaOCl on biofilm community structure but demonstrated poor bactericidal activity against dominant root canal pathogens, such as Streptococcus and Fusobacterium. Conclusion Under the initial anaerobic and subsequent aerobic culture conditions, 1% NaOCl exhibits potent bactericidal effects on young bacterial biofilms, but demonstrates limited efficacy against mature biofilms and certain root canal dominant bacteria (Streptococcus and Fusobacterium).
