The oral-brain axis: can periodontal pathogens trigger the onset and progression of Alzheimer's disease?

Alzheimer's disease (AD) is the most prevalent form of dementia, characterized by a progressive cognitive decline. Sporadic AD, accounting for more than 95% of cases, may arise due to the influence of environmental factors. It was reported that periodontitis, a common oral ailment, shares several risk factors with AD, including advanced age, smoking, diabetes, and hypertension, among others. Periodontitis is an inflammatory disease triggered by dysbiosis of oral microorganisms, whereas Alzheimer's disease is characterized by neuroinflammation. Many studies have indicated that chronic inflammation can instigate brain AD-related pathologies, including amyloid-ß plaques, Tau protein hyperphosphorylation, neuroinflammation, and neurodegeneration. The potential involvement of periodontal pathogens and/or their virulence factors in the onset and progression of AD by the oral-brain axis has garnered significant attention among researchers with ongoing investigations. This review has updated the periodontal pathogens potentially associated with AD, elucidating their impact on the central nervous system, immune response, and related pathological processes in the brain to provide valuable insights for future research on the oral-brain axis.

Photosensitive Hydrogels Encapsulating DPSCs and AgNPs for Dental Pulp Regeneration.

OBJECTIVE: Pulp regeneration with bioactive dentin-pulp complex has been a research hotspot in recent years. Stem cell therapy provided an interest strategy to regenerate the dental-pulp complex. Hence, this study aimed to evaluate the effects of photosensitive gelatin methacrylate (GelMA) hydrogel encapsulating dental pulp stem cells (DPSCs) and silver nanoparticles (AgNPs) for dental pulp regeneration in vitro. METHODS: First, the AgNPs@GelMA hydrogels were prepared by lithium phenyl-2,4,6-trimethyl-benzoyl phosphinate (LAP) initiation via blue-light emitting diode light. The physical and chemical properties of AgNPs@GelMA hydrogels were comprehensively analysed via scanning electron microscopy (SEM), and mechanical characterisation, such as swelling ability, degradation properties, and AgNP release profile. Then, AgNPs@GelMA hydrogels encapsulated DPSCs were used to establish an AgNPs@GelMA biomimetic complex, further analysing its biocompatibility, antibacterial properties, and angiogenic capacity in vitro. RESULTS: The results indicated that GelMA hydrogels demontrated optimal characteristics with a monomer:LAP ratio of 16:1. The physico-chemical properties of AgNPs@GelMA hydrogels did not change significantly after loading with AgNPs. There was no significant difference in AgNP release rate amongst different concentrations of AgNPs@GelMA hydrogels. Fifty to 200 µg/mL AgNPs@GelMA hydrogels could disperse E faecalis biofilm and reduce its metabolic activity . Furthermore, cell proliferation was arrested in 100 and 200 µg/mL AgNPs@GelMA hydrogels. The inhibition of 50 µg/mL AgNPs@GelMA hydrogels on E faecalis biofilm was above 50%, and the cell viability of the hydrogels was higher than 90%. The angiogenesis assay indicated that AgNPs@GelMA hydrogels encapsulating DPSCs could induce the formation of capillary-like structures and express angiogenic markers CD31, vascular endothelial growth factor , and von willebrand factor (vWF) in vitro. CONCLUSIONS: Results of this study indicate that 50 µg/mL AgNPs@GelMA hydrogels encapsulating DPSCs had significant antibacterial properties and angiogenic capacity, which could provide a significant experimental basis for the regeneration of the dentin-pulp complex.

A study on related factors affecting dental fear in preschool children.

This study aims to examine the manifestations of dental anxiety (DA) and its influencing factors during dental visits among preschool children. The data of 166 preschool children who visited the Department of Dentistry of our hospital from April 2021 to April 2023 with oral problems were retrieved. Their DA performance was investigated using the Children's Fear Survey Schedule-Dental Subscale (CFSS-DS). In addition, based on their general data and potential risk factor information, we performed logistic regression analysis to identify the factors influencing DA. Of the 166 questionnaires distributed, a total of 160 valid questionnaires were retrieved. The average CFSS-DS score was 35.57 ± 3.51 points. Sixty-six children had DA, resulting in an incidence rate of 41.25%. The top 5 items with the highest CFSS-DS scores were fear of needles, dentists, tooth extraction, drilling and oral anesthesia. When the 66 children with DA were classified into a DA group and a non-DA group, we observed significant differences in age distribution, dental experience, only child status, general anxiety symptoms, dental condition, family income and specific dental treatment procedures, particularly tooth extraction, between them (p < 0.05). Multivariate logistic regression analysis revealed that preschool children aged ≤4 years, those with prior dental experiences, single-child status, general anxiety symptoms, suboptimal dental health, family incomes below 100,000 yuan/year, and those undergoing specific dental procedures, such as tooth extractions, were independently associated with a higher risk of DA (p < 0.05). The incidence of DA in preschool children is high, and they exhibit substantial fear of needles, dentists, tooth extraction, drilling and oral anesthesia. Preschool children aged ≤4 years, with prior dental experiences, single-child status, the presence of general anxiety symptoms, suboptimal dental health, family incomes below 100,000 yuan/year, and those undergoing dental procedures, particularly tooth extraction, could be more predisposed to DA.

Local Spinal Cord Injury Treatment Using a Dental Pulp Stem Cell Encapsulated H2S Releasing Multifunctional Injectable Hydrogel.

Spinal cord injury (SCI) commonly induces nerve damage and nerve cell degeneration. In this work, a novel dental pulp stem cells (DPSCs) encapsulated thermoresponsive injectable hydrogel with sustained hydrogen sulfide (H2S) delivery is demonstrated for SCI repair. For controlled and sustained H2S gas therapy, a clinically tested H2S donor (JK) loaded octysilane functionalized mesoporous silica nanoparticles (OMSNs) are incorporated into the thermosensitive hydrogel made from Pluronic F127 (PF-127). The JK-loaded functionalized MSNs (OMSF@JK) promote preferential M2-like polarization of macrophages and neuronal differentiation of DPSCs in vitro. OMSF@JK incorporated PF-127 injectable hydrogel (PF-OMSF@JK) has a soft consistency similar to that of the human spinal cord and thus, shows a high cytocompatibility with DPSCs. The cross-sectional micromorphology of the hydrogel shows a continuous porous structure. Last, the PF-OMSF@JK composite hydrogel considerably improves the in vivo SCI regeneration in Sprague-Dawley rats through a reduction in inflammation and neuronal differentiation of the incorporated stem cells as confirmed using western blotting and immunohistochemistry. The highly encouraging in vivo results prove that this novel design on hydrogel is a promising therapy for SCI regeneration with the potential for clinical translation.

Metal-organic framework materials promote neural differentiation of dental pulp stem cells in spinal cord injury.

Spinal cord injury (SCI) is accompanied by loss of Zn2+, which is an important cause of glutamate excitotoxicity and death of local neurons as well as transplanted stem cells. Dental pulp stem cells (DPSCs) have the potential for neural differentiation and play an immunomodulatory role in the microenvironment, making them an ideal cell source for the repair of central nerve injury, including SCI. The zeolitic imidazolate framework 8 (ZIF-8) is usually used as a drug and gene delivery carrier, which can release Zn2+ sustainedly in acidic environment. However, the roles of ZIF-8 on neural differentiation of DPSCs and the effect of combined treatment on SCI have not been explored. ZIF-8-introduced DPSCs were loaded into gelatin methacryloyl (GelMA) hydrogel and in situ injected into the injured site of SCI rats. Under the effect of ZIF-8, axon number and axon length of DPSCs-differentiated neuro-like cells were significantly increased. In addition, ZIF-8 protected transplanted DPSCs from apoptosis in the damaged microenvironment. ZIF-8 promotes neural differentiation and angiogenesis of DPSCs by activating the Mitogen-activated protein kinase (MAPK) signaling pathway, which is a promising transport nanomaterial for nerve repair.

Identifying the key genes of Epstein-Barr virus-regulated tumour immune microenvironment of gastric carcinomas.

The Epstein-Barr virus (EBV) is involved in the carcinogenesis of gastric cancer (GC) upon infection of normal cell and induces a highly variable composition of the tumour microenvironment (TME). However, systematic bioinformatics analysis of key genes associated with EBV regulation of immune infiltration is still lacking. In the present study, the TCGA and GEO databases were recruited to analyse the association between EBV infection and the profile of immune infiltration in GC. The weighted gene co-expression analysis (WGCNA) was applied to shed light on the key gene modules associated with EBV-associated immune infiltration in GC. 204 GC tissues were used to analysed the expression of key hub genes by using the immunohistochemical method. Real-time PCR was used to evaluate the association between the expression of EBV latent/lytic genes and key immune infiltration genes. Our results suggested that EBV infection changed the TME of GC mainly regulates the TIICs. The top three hub genes of blue (GBP1, IRF1, and LAP3) and brown (BIN2, ITGAL, and LILRB1) modules as representative genes were associated with EBV infection and GC immune infiltration. Furthermore, EBV-encoded LMP1 expression is account for the overexpression of GBP1 and IRF1. EBV infection significantly changes the TME of GC, and the activation of key immune genes was more dependent on the invasiveness of the whole EBV virion instead of single EBV latent/lytic gene expression.

MSC based gene delivery methods and strategies improve the therapeutic efficacy of neurological diseases.

Mesenchymal stem cells (MSCs) are promising seed cells for neural regeneration therapy owing to their plasticity and accessibility. They possess several inherent characteristics advantageous for the transplantation-based treatment of neurological disorders, including neural differentiation, immunosuppression, neurotrophy, and safety. However, the therapeutic efficacy of MSCs alone remains unsatisfactory in most cases. To improve some of their abilities, many studies have employed genetic engineering to transfer key genes into MSCs. Both viral and nonviral methods can be used to overexpress therapeutic proteins that complement the inherent properties. However, to date, different modes of gene transfer have specific drawbacks and advantages. In addition, MSCs can be functionalized through targeted gene modification to facilitate neural repair by promoting neural differentiation, enhancing neurotrophic and neuroprotective functions, and increasing survival and homing abilities. The methods of gene transfer and selection of delivered genes still need to be optimized for improved therapeutic and targeting efficacies while minimizing the loss of MSC function. In this review, we focus on gene transport technologies for engineering MSCs and the application of strategies for selecting optimal delivery genes. Further, we describe the prospects and challenges of their application in animal models of different neurological lesions to broaden treatment alternatives for neurological diseases.

Progress on the cell therapy strategy of mesenchymal stem cells / 口腔疾病防治

@#Cell therapy based on mesenchymal stem cells (MSCs) has been a hot research topic in recent years, including the traditional cell therapy strategy based on living cells and the new cell-free therapy strategy based on soluble proteins or bioactive molecules such as extracellular vesicles (EVs). At present, MSC-induced cells have mature functions and specific structures, and insitu transplantation combined with biomaterials or organic technology has greatly improved the settlement rate and function. On the other hand, as the large-scale culture technique and EVs separation technique evolve, it is possible to obtain a large number of pure EVs, and EVs are gradually becoming a hot spot of current research. An increasing number of studies have shown that the therapeutic effect of MSCs not only occurs by implantation and differentiation but also manifests as the paracrine effect of MSCs. In this review, we discuss the emerging outcomes of cell therapies and acellular therapies to alleviate these pathological conditions.

Orthodontic treatment with clear aligners for a patient with chronic periodontitis.

This case report describes the treatment of an adult female patient with a history of periodontal disease, Class I malocclusion with extrusion, dental spaces, and pathologic tooth migration. The patient was treated with clear aligners, which effectively controlled the strength and direction of orthodontic forces after 3 months of systematic periodontal treatment. The Peer Assessment Rating (PAR) index was calculated from study models before and after treatment. The pretreatment PAR score was 24, and the posttreatment PAR score was 4. The PAR score for this patient changed by 83%. Satisfactory appearance and good function were achieved for this patient.

Characteristics of culture-condition stimulated exosomes or their loaded hydrogels in comparison with other extracellular vesicles or MSC lysates.

Recently, it has become popular to study the use of extracellular vesicles (EVs) secreted by stem cells to repair damaged tissues or lost cells. Various cell types and physiological fluids release EVs, and they play an important role in cell-to-cell communication. Moreover, EVs have been implicated in important processes, such as immune responses, homeostasis maintenance, coagulation, inflammation, cancer progression, angiogenesis, and antigen presentation. Thus, EVs participate in both physiological and pathological progression. The main classes of EVs include exosomes, microvesicles (MVs), and apoptotic bodies (ApoBDs). Exosomes, which carry a mass of signal molecules such as RNA, DNA, proteins, and lipids, are the most important of these EVs subsets. Currently, exosomes are generating substantial interest in the scientific community. Exosomes loaded hydrogels or under different cultural environments exhibit different properties and functions. Therefore, the exosomes obtained from different sources and conditions are worth reviewing. More importantly, no review article has compared the different EVs, such as exosomes, MVs, ApoBDs, and mesenchymal stem cell (MSC) lysates, which are special soluble substances. The differentiation between EVs and MSC lysates is a logical approach. Accordingly, this review provides an update on the latest progress in studying the roles of culture-condition stimulated exosomes or their loaded hydrogels and the differentiation between exosomes, MVs, ApoBDs, and MSC lysates. Published studies were retrieved from the PubMed® database for review.

AM1241-Loaded Poly(ethylene glycol)-Dithiothreitol Hydrogel Repairs Cranial Bone Defects by Promoting Vascular Endothelial Growth Factor and COL-1 Expression.

Objective: To explore the repair effect of the prepared drug-loaded AM1241 poly(ethylene glycol)-dithiothreitol (PEG-DTT) hydrogel on cranial bone defects in SD rats. Methods: The PEG-DTT hydrogel under borax catalysis was quickly prepared, and the characterization of the material was observed by a scanning electron microscope. The effect of AM1241 on cell activity and bone tissue differentiation was tested. The SD rat model of cranial bone defect was established, and the defect was repaired by injecting the prepared hydrogel into the defect. The defect was divided into four groups, namely, sham group, blank group, PEG-DTT group, and PEG-DTT + AM1241 group. The rats were euthanized, and whole cranial bone was taken out for micro-CT and histological observation. Results: The prepared hydrogel is porous; it is liquid when heated to 80°C and a hydrogel when cooled to 25°C. 5-10 µM AM1241 increased osteoblast activity. A moderate amount of AM1241 can promote osteogenic differentiation. Both the PEG-DTT group and PEG-DTT + AM1241 group showed obvious new bone tissue formation, but the PEG-DTT + AM1241 group had a better effect. In addition, the new bone tissue in the PEG-DTT + AM1241 group was significantly more than that in the other groups. Conclusion: The prepared AM1241-loaded PEG-DTT hydrogel showed a good repair effect on SD rats with cranial bone defects. It can be used as materials for cranial bone repair in SD rats with cranial bone defects, but the repair effect is weaker than that of normal bone. These results provide a theoretical and practical basis for its further clinical application.

Influence of Fluoride-Resistant Streptococcus mutans Within Antagonistic Dual-Species Biofilms Under Fluoride In Vitro.

The widespread application of fluoride, an extremely effective caries prevention agent, induces the generation of fluoride-resistant strains of opportunistic cariogenic bacteria such as fluoride-resistant Streptococcus mutans (S. mutans). However, the influence of this fluoride-resistant strain on oral microecological homeostasis under fluoride remains unknown. In this study, an antagonistic dual-species biofilm model composed of S. mutans and Streptococcus sanguinis (S. sanguinis) was used to investigate the influence of fluoride-resistant S. mutans on dual-species biofilm formation and pre-formed biofilms under fluoride to further elucidate whether fluoride-resistant strains would influence the anti-caries effect of fluoride from the point of biofilm control. The ratio of bacteria within dual-species biofilms was investigated using quantitative real-time PCR and fluorescence in situ hybridization. Cristal violet staining, scanning electron microscopy imaging, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide assay were used to evaluate biofilm biomass, biofilm structure, and metabolic activity, respectively. Biofilm acidogenicity was determined using lactic acid and pH measurements. The anthrone method and exopolysaccharide (EPS) staining were used to study the EPS production of biofilms. We found that, in biofilm formation, fluoride-resistant S. mutans occupied an overwhelming advantage in dual-species biofilms under fluoride, thus showing more biofilm biomass, more robust biofilm structure, and stronger metabolic activity (except for 0.275 g/L sodium fluoride [NaF]), EPS production, and acidogenicity within dual-species biofilms. However, in pre-formed biofilms, the advantage of fluoride-resistant S. mutans could not be fully highlighted for biofilm formation. Therefore, fluoride-resistant S. mutans could influence the anti-caries effect of fluoride on antagonistic dual-species biofilm formation while being heavily discounted in pre-formed biofilms from the perspective of biofilm control.

Hsa_circRNA_0001971 contributes to oral squamous cell carcinoma progression via miR-186-5p/Fibronectin type III domain containing 3B axis.

BACKGROUND: Circular RNAs (circRNAs) are closely associated with the progression of oral squamous cell carcinoma (OSCC). circRNA_0001971 has been proved to accelerate the OSCC development. Here, we aim to identify the new molecular mechanism of hsa_circRNA_0001971 (circRNA_0001971) in OSCC. METHODS: The levels of circRNA_0001971, miR-186-5p, and fibronectin type III domain containing 3B (FNDC3B) in tissues and cells were verified by qRT-PCR or Western blotting. The interaction between circRNA_0001971, miR-186-5p, and FNDC3B was identified by bioinformatics analysis, luciferase assay, and RIP assay. The effect of circRNA_0001971/miR-186-5p/FNDC3B axis on OSCC cell proliferation, migration, and invasion by cell functional experiments including CCK8, wound healing, and transwell assays. RESULTS: Our study displayed that circRNA_0001971 and FNDC3B were elevated in OSCC, whereas miR-186-5p was declined in OSCC. Silencing circRNA_0001971 attenuated the malignancy of OSCC cells by suppressing proliferation, migration, and invasion. In OSCC cells, circRNA_0001971 sponged miR-186-5p to enhance FNDC3B. Due to the interaction between circRNA_0001971, miR-186-5p, and FNDC3B, FNDC3B overexpression relieved the negative function of silencing circRNA_0001971 in OSCC cells. CONCLUSION: Overall, our study discovered that circRNA_0001971 was a tumor promoter in OSCC progression by targeting miR-186-5p/FNDC3B axis.

The optimal activation of plastic aligner for canine distal movement: a three-dimensional finite element analysis.

This study aimed to investigate the optimal activation of plastic aligner for the canine distal movement by combining the stress and strain of periodontal ligament. Computer-aided design models of the upper canine, periodontal ligament, alveolar bone, and plastic aligner were constructed. The stresses and strains of periodontal ligament were acquired by fitting plastic aligner on the canine, which will cause the canine distal-direction movement. The activation of plastic aligner was set into 12 groups, including 0.050, 0.100, 0.125, 0.150, 0.175, 0.200, 0.225, 0.250, 0.275, 0.300, 0.350, and 0.400 mm. Assuming the volume-averaged hydrostatic stress (VAHS) ranging from 4.7 to 16 kPa to be the optimal stress, and an average strain no less than 0.3 to be the optimal strain. The optimal activation of plastic aligner was acquired based on the optimal stress and average strain. As the activation increased, the stress and strain of periodontal ligament increased visibly. The degree of activation of plastic aligner was nonlinearly and positively related to VAHS and average strain. According to the fitted curves, the activation corresponding to the optimal stress was 0.07-0.24 mm and the activation was not less than 0.21 mm based on the optimal strain. The optimal activation of plastic aligner for the canine distal movement was 0.21-0.24 mm in this study. The degree of activation affects the force system of orthodontic tooth movement, and it should be taken into consideration to obtain healthy and efficient tooth movement. The activation with 0.21-0.24 mm seems optimal for orthodontic tooth movement in the plastic aligner system in this study.

Advances in isolation and extraction standardization and clinical translation of exosomes / 口腔疾病防治

@#Exosomes are phospholipid bilayer vesicles secreted by living cells that can carry a variety of signaling molecules, such as RNA, DNA, protein, and lipids. Exosomes play a role in the transmission of signaling molecules between cells, thus regulating many physiological and pathological processes. The methods of extracting exosomes include differential centrifugation, density gradient centrifugation, exclusion chromatography, ultrafiltration, coprecipitation, polymer immune affinity, microfluidic separation technology, etc. Each of these extraction technologies has advantages and disadvantages; however, there is no unified international standard. In addition, the expression of specific proteins and genetic material of exosomes from different cell sources are different; thus, their expression characteristics and functions are also distinctive. Based on this situation, research on exosomes is limited to preclinical studies, and difficulties and challenges still exist in clinical application. This paper summarizes the progress of research in the field of exosomes, to understand the characteristics, modification and application of exosomes from different cell sources, and to summarize their advantages and disadvantages as well as challenges, which can help researchers better understand and master the performance of exosomes. Furthermore, improvement of standard procedures in the extraction and manufacturing of exosomes is important, as it will provide a reference for researchers to carry out exosome-related translational clinical research.

Expression of Dickkopf-related Protein 1 in Patients with Temporomandibular Osteoarthritis after Treatment with Hyaluronic Acid.

We previously reported that the increased expression of Dickkopf-related protein 1 (DKK1) is positively related to vascular endothelial growth factor in the synovial fluid from patients with temporomandibular joint disorders (TMDs). DKK1 is involved in angiogenic activities in the TMD synovium in vitro, but the expression of DKK1 after treatment of TMD-osteoarthritis (TMD-OA) with hyaluronic acid (HA) remains unknown. In this study, we assessed the expression of DKK1 in the synovial fluid of TMD-OA patients before and after treatment with HA via enzyme-linked immunosorbent assay. We also investigated the role of DKK1 in TMD-OA via immunohistochemical staining. The relationship between the expression of DKK1 and the clinicopathological characteristics was determined by Pearson analysis. The results showed that the expression of DKK1 was significantly decreased after treatment with HA. Correlation analyses indicated that the expression of DKK1 in the TMD-OA samples was closely correlated with mouth opening and pain. These findings suggest that DKK1 could play an important role in the pathogenesis and treatment of TMD. Reduction of the pain by HA treatment may be correlated with the decreased expression of DKK1.

Effect of puerarin on osteogenic differentiation of human periodontal ligament stem cells.

OBJECTIVE: To investigate the effects of the flavonoid, puerarin, on osteogenic differentiation of human periodontal ligament stem cells (PDLSCs). METHODS: Human PDLSCs were isolated from patients undergoing orthodontic treatment, and the cell surface markers CD146, CD34, CD45, and STRO-1 were identified by immunofluorescence. Cell proliferation was detected by MTT assay; alkaline phosphatase (ALP) activity was measured, and calcium deposition was detected by alizarin red staining. PCR was then used to detect the distributions of COL-I, OPN, Runx2, and OCN, genes related to osteogenic differentiation. RESULTS: Staining was positive for cytokines CD146, CD34, CD45, and STRO-1 in the experimental group; staining was also positive for silk protein, but negative for keratin. After 7 days of culture, exposure to puerarin significantly promoted the level of intracellular ALP; increased puerarin concentration led to increased intracellular ALP. Red mineralized nodules appeared upon exposure to puerarin and the number of nodules was concentration-dependent. PCR analysis revealed that COL-I, OPN, Runx2, and OCN expression levels increased as puerarin concentration increased. CONCLUSIONS: Exposure to puerarin can promote proliferation and ALP activity in human PDLSCs, thus promoting both molecular and osteogenic differentiation; these findings may provide a theoretical basis for the clinical treatment of periodontal disease with puerarin.

Knockdown RPL29 Gene Can Inhibit the Proliferation, Invasion of Squamous Cell Carcinomas.

OBJECTIVE: Gingival squamous cell carcinoma (GSCC) is one of the most common malignancies. Endogenous ribosomal protein L29 (RPL29) has been previously proven to be up-regulated in cancer tissues. However, RPL29 expression in GSCC has not been described. METHODS: The knockdown of RPL29 gene in GSCC cells was carried out to study the influence of RPL29 silencing on GSCC cells. RESULTS: We investigated the influence on cell proliferation, invasion, and related biomarkers, which led us to confirm that all were repressed by the knockdown of RPL29. CONCLUSION: The role of RPL29 should lead to a better understanding of the development and progression of human GSCC.

CBCT study of three-dimensional morphological characteristics of upper airway in children and adolescents with skeletal class Ⅲ malocclusion / 口腔疾病防治

Objective@#To investigate the three-dimensional morphological characteristics of the upper airway in children and adolescents with skeletal class Ⅲ malformation and to explore the relationship between craniofacial structure and upper airway morphology.@*Methods @#Ninety cases of malocclusion aged 3-18 years were collected. In addition, 45 cases of type I and type Ⅲ were classified into three age groups with 15 cases in each group: 3-6 years old, 7-12 years old and 13-18 years old. CBCT was taken, and the scanning data of CBCT were reconstructed by the third-party software Invivo 5. The volume, minimum cross-sectional area, height and the ratio of sagittal diameter to transverse diameter at the minimum cross-sectional area of each segment of the upper airway were measured. The difference of the upper airway between skeletal class I and skeletal class Ⅲ in each age group was analyzed and compared by group t test.@*Results @# No significant differences in the upper airway indexes were noted between skeletal class I and skeletal class Ⅲ(P > 0.05) in the 3-6 years old group. In the 7-12 years old group, the total volume of skeletal class Ⅲ upper airway (16.25 ± 3.69 cm 3), nasopharyngeal segment (2.39 ± 0.90 cm 3), and palatopharyngeal segment (5.24 ± 1.14 cm 3) were reduced compared with the total volume of the skeletal class I upper airway (20.98 ± 6.25 cm 3) , nasopharyngeal segment (4.21 ± 1.09 cm 3), and palatopharyngeal segment (8.18 ± 2.02 cm 3), respectively, the differences were statistically significant (tVtotal=2.526, tVnose=4.999, tVpalate=4.908, P < 0.05). In the 13-18 years old group, only nasopharyngeal segment volume (3.83 ± 0.90 cm 3) was reduced in skeletal type I (4.69 ± 1.34 cm 3); the difference was statistically significant (t=2.053, P < 0.05).@*Conclusion@# Age is an important factor affecting the morphology and structure of upper airway in skeletal Ⅲ malocclusion.