Objective To investigate whether ursolic acid （UA） can ameliorate osteoporosis-related jaw bone injuries by alleviating the senescence of bone marrow mesenchymal stem cells （BMMSCs）. Methods An ovariectomized osteoporotic mouse model was established. After UA intervention，Micro-CT was used to evaluate the trabecular microstructure of the femur and jaw bone. Integrated multidatabase analysis，KEGG pathway enrichment，the CellAge database，and machine learning methods were employed to screen key senescence-related genes through which UA exerts its effects on osteoporosis. Based on single cell transcriptomic data from osteoporotic bone，the expression profiles of these key genes across different cell types were analyzed，and senescence scores for distinct cell populations were calculated using the SenMayo senescence-associated gene set. In vitro，BMMSCs were induced to senesce by H₂O₂ and then treated with UA. Senescence phenotypes and osteogenic capacity were assessed through SA-β-gal staining，ALP/ARS staining，and RT-PCR. Results Micro-CT analysis demonstrated that UA significantly improved trabecular bone micro-architecture in both the femur and jaw of osteoporotic mice. Bioinformatics analyses revealed that the potential targets of UA in osteoporosis were significantly enriched in the p53 signaling pathway and cellular senescence-related pathways. Single-cell transcriptomic analysis showed that multiple key senescence-related genes were expressed in BMMSCs，and senescence scoring based on the SenMayo gene set consistently indicated a higher level of senescence in BMMSCs from osteoporotic samples. Experiments further demonstrated that UA significantly alleviated hydrogen peroxide-induced senescent phenotypes in BMMSCs. Conclusion UA can ameliorate osteoporosis-associated bone injuries by alleviating senescence in BMMSCs，thereby exhibiting a potential bone-protective effect on the jaw.

Objective To investigate the spatiotemporal expression characteristics and biological functions of CD44 during the development of the mandibular first molar crown in mice. Methods Immunohistochemical staining was performed to examine CD44 protein localization and expression in the mandibular first molar tooth germs at different developmental stages from E11.5 （embryonic day 11.5） to PN7 （postnatal day 7）. Real-time quantitative PCR was used to analyze the mRNA expression level of CD44. To further explore the function of CD44，mouse mandibular first molar dental germs at E16.5 were isolated for organ culture and transfected with small interfering RNA to knock down CD44 expression. The overall morphology of the dental germs，their width and height，as well as the differentiation status of ameloblasts and odontoblasts，collagen secretion，and the formation of predentin were evaluated using HE staining，Masson trichrome staining，and immunofluorescence staining techniques. Results At the initiation stage of tooth germ development （E11.5），CD44 was not significantly expressed in the dental plate epithelium and the underlying mesenchyme. In the bud stage （E13.5），CD44 showed weak expression in the dental epithelial cells. From the cap stage （E14.5） to the late bell stage （E18.5），CD44 was expressed in all types of cells in the enamel organ，and was highly expressed in the inner enamel epithelium and stratum intermedium. After birth （PN1 to PN7），CD44 continued to be highly expressed in the ameloblasts and stratum reticulum. From PN3 onwards，positive signals were also detected in the sub-odontoblastic layer near the odontoblasts at the tooth cusps. RT-qPCR results showed that the expression level of CD44 mRNA reached its peak at PN5. The culture experiment of dental germs showed that compared with the control group，the width and height of the dental germ in the siCD44 group were reduced； the differentiation of ameloblasts and odontoblasts was inhibited； collagen secretion was significantly decreased，and the formation of predentin was impaired. Conclusion CD44 exhibits dynamic spatiotemporal expression characteristics during the development of the mandibular first molar crown in mice. Inhibiting its expression can affect the morphology of the dental germ，key cell differentiation，and the formation of predentin，suggesting that CD44 plays an important role in this process.

Objective To investigate the effect of coffee on the osteogenic differentiation of rat bone marrow mesenchymal stem cells （BMMSCs） and preliminarily elucidate its relationship with the Wnt/β-catenin signaling pathway. Methods Rat BMMSCs were isolated and cultured using the whole bone marrow adherence method. Coffee-conditioned medium was prepared at different concentrations，and the optimal concentration was selected based on alkaline phosphatase （ALP） staining. Changes in osteogenesis-related markers were observed via qRT-PCR and Western blot，and alterations in the gene and protein expression levels of β-catenin were detected. Results Rat BMMSCs were successfully isolated and cultured. ALP activity assay identified 0.1 mg/mL as the optimal concentration of coffee-conditioned medium. Further experiments showed that this concentration had no significant effect on the proliferation of rat BMMSCs during the first 3 days but inhibited their proliferation from Day 5 to 9. Coffee-conditioned medium suppressed the expression of osteogenic markers in rat BMMSCs and concurrently downregulated the expression of proteins related to the Wnt/β-catenin signaling pathway. Conclusion Coffee-conditioned medium can inhibit the osteogenic differentiation of rat BMMSCs，and its mechanism may be associated with the suppression of the Wnt/β-catenin signaling pathway.

Objective To evaluate the biomechanical response of anterior implant-supported restorations under traumatic impact loading with different palatal cervical bone plate thicknesses. Methods A three-dimensional finite element model of an anterior implant-supported restoration was established based on CBCT data from a healthy adult male. The palatal cervical bone plate thickness was set to 0，0.5，and 1.0 mm，while buccal and incisal impact loads were applied，resulting in six models using a two-factor design. Transient dynamic finite element analysis was conducted to determine the peak time-history responses of implant von Mises stress and the maximum and minimum principal stresses in the surrounding cortical bone. Results Peak implant von Mises stress was concentrated at the implant-abutment junction and remained below the yield strength of titanium. In contrast，the maximum and minimum principal stresses of the cortical bone exceeded their strength thresholds at the moment of impact. Increasing palatal cervical bone plate thickness led to reduced implant and cortical bone stress peaks under both impact conditions，with a greater reduction observed under incisal impact. Overall，buccal impact generated higher stress levels than incisal impact. Conclusion Both palatal cervical bone plate thickness and impact direction significantly affect the traumatic biomechanical behavior of anterior implant-supported restorations. Traumatic impact loading may increase the risk of mechanical overload in peri-implant bone and should be considered in clinical planning and risk assessment for anterior esthetic implant restorations.

Objective To investigate the effect of inhibiting macrophage migration inhibitory factor（MIF） activity on bone resorption in rat peri-implantitis. Methods Twenty male Sprague-Dawley（SD） rats were randomly divided into four groups： blank control group，inflammation control group，inflammation treatment group，and inflammation solvent group. After extracting the bilateral first molars of each rat，titanium alloy cortical bone screws were immediately implanted. In all inflammation groups，peri-implantitis models were constructed by ligating the implants with silk thread. Subsequently，the peri-implant gingiva of rats in the blank control group and inflammation control group was injected with normal saline； the inflammation treatment group was injected with MIF inhibition ISO-1，and the inflammation solvent group was injected with dimethyl sulfoxide（DMSO） solution. Micro-CT scanning was used to observe the peri-implant bone resorption，and analyze bone mineral density（BMD） and bone volume fraction（BV/TV）. HE staining was performed to observe the histological manifestations of peri-implant tissues. Immunohistochemical analysis was used to detect the protein expression levels of IL-6 and IL-10. Results Compared with the blank control group，the BMD and BV/TV in the three inflammation groups were significantly decreased（P<0.05）； HE staining showed inflammatory cell infiltration and fibrous connective tissue formation； the expression levels of IL-6 and IL-10 were increased（P<0.05）. After local inhibition of MIF activity，compared with the inflammation control group and inflammation solvent group，the inflammation treatment group showed increased BMD and BV/TV，decreased IL-6 expression，and increased IL-10 expression（P<0.05）. Conclusion Inhibition of MIF activity can alleviate bone loss in peri-implantitis，and the mechanism may be related to the decrease in IL-6 expression and the increase in IL-10 expression.

Objective To investigate the effect of an injectable photo-crosslinking hydrogel loaded with strontium ions （PLSr²⁺@HAMA） on osteogenic differentiation-related phenotypes of human periodontal ligament stem cells （hPDLSCs） and to analyze its potential molecular regulatory features through transcriptomic analysis. Methods Cell viability of hPDLSCs was evaluated using the CCK-8 assay. Alizarin Red S （ARS） staining，real-time quantitative PCR （RT-qPCR），and Western blot （WB） were used to detect changes in osteogenic-related markers. RNA-seq was performed，and bioinformatic analysis tools were used to conduct functional enrichment and protein-protein interaction network analysis of differentially expressed genes. Results PLSr²⁺@HAMA hydrogel did not significantly affect cell proliferation. ARS staining showed enhanced mineralization nodule formation. RT-qPCR and WB results indicated increased expression of alkaline phosphatase （ALP） and bone morphogenetic protein 2 （BMP2）. Transcriptomic analysis revealed that differentially expressed genes were mainly associated with extracellular matrix regulation，signal transduction，and cellular responses. Several hub genes related to osteogenesis and matrix regulation were identified. Conclusion PLSr²⁺@HAMA hydrogel promotes osteogenic differentiation of hPDLSCs and induces changes in osteogenic-related transcriptional responses，providing experimental support for its application in periodontal tissue regeneration.

Objective To compare mandibular incisor root resorption and alveolar bone remodeling in adults with skeletal Class Ⅲ malocclusion treated by orthodontic camouflage versus combined orthodontic-orthognathic therapy. Methods Thirty adults were enrolled and allocated to a camouflage group （CA，n=15） or a combined treatment group （CO，n=15）. Cone-beam CT （CBCT） was used to measure root length，labial/lingual vertical bone level （La-/L-VBL），and alveolar bone thickness （ABT） at multiple levels before and after treatment； in the CO group，an additional presurgical decompensation time point was assessed. Within-group changes were tested with paired t tests or repeated-measures ANOVA，between-group differences with independent-samples t tests. Results Both groups showed mild root shortening，with significant increases in L-VBL. La-VBL changed little in the CA group but increased markedly after decompensation in the CO group and then stabilized postoperatively. Lingual ABT decreased significantly in both groups； labial changes were minimal in CA. In CO，labial cervical thinning with apical thickening was observed during decompensation，with the same direction of change but smaller magnitude after surgery. Overall，the reduction in lingual ABT was greater in CA，whereas labial mid-apical thickness recovered more readily in CO. Conclusion The magnitude of root resorption was similar between approaches. The lingual plate is the principal site of bone loss； camouflage more readily induces widespread thinning and crestal apicalization，while the combined approach shows better postoperative recovery of labial mid-apical bone.

Objective To investigate the impact of bilateral temporomandibular joint disc repositioning on mandibular morphology and position，and to analyze the relationship between postoperative changes in condylar position and condylar bone regeneration. Methods A retrospective study was conducted，including patients who underwent bilateral temporomandibular joint anterior disc displacement without reduction（ADDWoR） and disc repositioning surgery from April 2020 to December 2024. Preoperative（T0），1-month postoperative（T1），and more than 6-month postoperative（T2） cone beam computed tomography（CBCT） and magnetic resonance imaging（MRI） were measured using Materialise ProPlan CMF3.0 software. The evaluation indicators included the positional relationship of the mandible relative to the cranial base（e.g.，SNB，ANB），mandibular morphology（e.g.，mandibular ramus height，body length），condylar position（e.g.，anterior，superior，and posterior joint spaces），and condylar bone regeneration. The measurement results were analyzed using the Friedman test，Chi-square test，Fisher’s exact test，and Mann-Whitney U test. A P value<0.05 was considered statistically significant. Results Compared with T0，SNB increased significantly at both T1 and T2 （P<0.001），with no significant difference between T1 and T2 （P>0.05）. ANB，overjet，and the Pog-G' distance decreased significantly at T1 and T2 （P<0.001）. No significant differences were observed between T1 and T2 for ANB and Pog-G' （P>0.05）. The superior and posterior joint spaces increased significantly at T1 （P<0.001），then decreased significantly at T2 compared with T1 （P<0.001），but remained greater than at T0 （P<0.01）. Compared with T0，ramus height and mandibular body length increased significantly at T2 （P<0.05）. The proportion of condylar bone regeneration at T2 was 67.44% （58/86），distributed predominantly along the posterior slope，followed by the superior surface and the anterior slope.The highest regeneration rate occurred when the posterior-to-anterior joint space ratio was ≥1.5（P<0.05）. Conclusion Bilateral temporoman-dibular joint disc repositioning surgery effectively improves the disc-condyle relationship and induces adaptive changes in the morphology and position of the mandible and condyle. Postoperative condylar position reconstruction is associated with condylar bone regeneration，with an increased posterior-superior joint gap promoting condylar bone regeneration.

This study presents a complex clinical case of minimally invasive esthetic restoration for mandibular anterior diastema using digital double-guide technology-assisted composite resin direct bonding. The patient exhibited abnormally proportioned dental crowns leading to wide diastema. Digital technology was employed to reconstruct optimal tooth morphology，complemented by 3D-printed lingual morphological guides and labial contour guides. The double-guide system enabled precise control of composite resin layering and morphological construction，achieving minimally invasive esthetic rehabilitation. This case establishes a standardized protocol for diastema restoration，demonstrating particular clinical significance for morphological and functional reconstruction in wide interdental spacing cases.

Dental caries，as a globally prevalent oral disease，its prevention and treatment critically depends on effectively inhibiting the formation of cariogenic bacterial biofilms and promoting the remineralization of demineralized dental hard tissues. Antibacterial-remineralizing materials，combining the dual functions of combating pathogenic microorganisms and repairing dental hard tissues，have become a current research hotspot. This article systematically reviews the latest research progress of antibacterial-remineralizing materials for the prevention and treatment of dental caries. It focuses on discussing the research status and existing challenges of four material systems： inorganic composite systems，organic polymer composite systems，bioactive molecule-based materials，and smart responsive materials，to provide new material strategies for effectively preventing and managing tooth decay.

Early childhood caries（ECC） is one of the most prevalent chronic pediatric diseases worldwide，posing significant challenges to children’s health. Recent advances in multi-omics technologies have provided novel insights into the structural and functional characteristics of ECC-associated oral microbial communities. Research evidence confirms that ECC development is closely linked to oral microbial imbalance，characterized by changes in dominant bacterial species，altered diversity，and shifted functional expression，revealing dynamic microbial changes and host-microbe interactions during disease progression. These findings demonstrate how oral microbiome dysbiosis drives ECC through structural and functional alterations in the microbial community. Machine learning has enhanced high-throughput data analysis，which further advances ECC prediction models with integrated models combining microbiome features and host factors demonstrating superior predictive accuracy. However，current research still faces limitations including insufficient sample sizes and limited model generalizability. Future directions should focus on expanding microbial community profiling to understudied members，optimizing multi-omics data integration through systems biology approaches，and developing ultrasensitive detection methods for low-abundance biomarkers，which are all critical for ECC precise prediction and personalized prevention.

Severe periodontitis leads to periodontal tissue defects，alveolar bone resorption，pulp necrosis，and tooth loosening，so there is an urgent need to find suitable periodontal bone repair materials for treatment. Currently，common methods used to repair bone defects，such as autologous bone and allogeneic bone transplantation，platelet products，and （guided tissue regeneration，GTR） strategies，have many flaws. Hydrogels，with their unique advantages，have stood out and have been a hot topic in research in recent years. This article summarizes the advantages and disadvantages of hydrogels，lists the properties and research progress of several traditional hydrogels and novel hydrogels at present，aiming to provide new ideas for the application of hydrogels in the field of repair and treatment of periodontitis-induced bone defects.