With the rapid aging of the global population, the demand for prosthodontic rehabilitation of partial edentulism continues to increase. Among the available treatment options, removable partial dentures remain an essential clinical modality for restoring partially edentulous arches and masticatory function because of their broad indications, minimal invasiveness, and cost-effectiveness. However, unlike fixed prosthodontics, which have undergone substantial digitalization, removable partial denture therapy is characterized by dual tooth-tissue support, complex biomechanics, and highly variable anatomical morphology. As a result, the digital design and fabrication of removable partial dentures have long faced major bottlenecks, including limited standardization, steep learning curves, and heavy dependence on expert experience. In recent years, artificial intelligence (AI) has undergone a paradigm shift from early expert systems to machine learning and deep learning, creating new opportunities to address the complexity and precision demands of removable partial denture design. Based on a comprehensive literature review and our team's clinical experience, this article systematically elaborates on the specific applications and normative standards of AI throughout the entire removable partial denture fabrication workflow. In the data acquisition phase, we emphasize multimodal data fusion and digital pressure impression strategies. In the intelligent diagnosis and planning phase, deep learning is utilized to achieve the automatic identification of edentulous areas and undercuts, while machine learning and expert systems assist in abutment selection and treatment plan generation. Regarding automated design logic, the article analyzes the process from the intelligent planning of the common path of insertion to parametric design based on biomechanical optimization. At the clinical operation level, a standardized human-machine collaborative workflow of “AI generation-clinician review-local fine-tuning” is proposed. In terms of ethics and accountability, the principles of algorithmic transparency and “the clinician as the ultimate responsible subject” are emphasized. Furthermore, integrating clinical practice, this article innovatively proposes a “capability grading system for AI-assisted removable partial denture design (comprising the auxiliary analysis level, the rule-based design level, and the intelligent adaptive level)”. The aim is to offer practical recommendations for dental clinicians, dental technicians, and researchers, thereby facilitating the transition of removable partial denture prosthodontics toward greater precision, intelligence, and standardization.
Objective To investigate the impact of activin receptor type-1 (ACVR1) on odontoblastic differentiation and dentin formation based on single-cell RNA sequencing. Methods A correlation analysis of ACVR1 with odontogenesis-related transcription factors was performed using single-cell data from healthy wild-type adult mouse incisors obtained from the Gene Expression Omnibus database (GSE146123). This experiment was approved by the Institutional Animal Care and Use Committee of the affiliated institution. Conditional knockout mice with ACVR1 deleted in the dental mesenchyme were generated using the Cre-LoxP system (experimental group: Osterix-Cre; ACVR1fx/-, control group: Osterix-Cre; ACVR1fx/+). Dental pulp tissue was extracted from the incisors of 3-week-old mice to prepare single-cell suspensions for 10 × Genomics single-cell transcriptome sequencing. Quality control, normalization, dimensionality reduction, and Harmony batch effect correction were performed using the Seurat pipeline, followed by UMAP dimensionality reduction visualization and cell subpopulation identification. Monocle was used for pseudotime analysis to infer cell differentiation trajectories, and changes in transcription factors positively correlated with ACVR1 were analyzed at the single-cell data level. Immunofluorescence staining was employed to validate the localization and expression changes of the key transcription factor Osterix and the odontoblast-specific protein DSPP. Results Sp7/Osterix is widely expressed in the incisor mesenchyme of mice (GSE146123). Using Osterix-Cre, ACVR1 was effectively knocked out in the mesenchyme. Gene correlation analysis between ACVR1 and key odontogenic genes showed positive correlations between ACVR1 and genes such as Msx1, Msx2, and Sp7. Single-cell atlases of incisor dental pulp tissue from “Osterix-Cre; ACVR1fx/-” and “Osterix-Cre; ACVR1fx/+” mice were then constructed. The most significant increase in the proportion of pre-odontoblasts was in the experimental group, along with downregulated expression of key genes related to odontoblastic differentiation and polarization in this subpopulation. Differential gene enrichment analysis across all mesenchymal subpopulations indicated downregulated expression of most genes associated with dentin formation. Finally, as observed through single-cell differential gene analysis, pseudotime expression analysis, and immunofluorescence validation, the expression of Sp7 and DSPP were significantly downregulated in the experimental group. Conclusion The ACVR1 gene may promote odontoblastic differentiation and subsequently affect dentin formation through transcription factors such as Sp7, Msx1, and Msx2.
Objective To investigate the effect of specific deletion of SET-domain-containing 2 (Setd2) in dental germ mesenchymal cells on early tooth development and provide a research basis for exploring the etiology of dental developmental disorders. Methods This study was approved by the Animal Care and Ethical Committee of Wuhan University. Wnt1Cre mice with a C57BL/6J background were crossed with Setd2flox/flox mice to generate the Setd2 knockout experimental group (Wnt1Cre; Setd2flox/flox) and the control group (Setd2flox/flox). Tail tissues of mouse embryos were collected at embryonic day (E) 13.5, E15.5, and E18.5 for polymerase chain reaction (PCR)-based genotyping, and embryonic heads were collected for paraffin sectioning to observe the development of the first mandibular molar germs. Immunohistochemical (IHC) staining was performed to verify the specific knockout of Setd2 in dental germ mesenchymal cells; hematoxylin and eosin (HE) staining and subrenal culture were used to evaluate the effect of Setd2 knockout in dental germ mesenchymal cells on tooth development; Ki67 staining and a terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay were employed to evaluate the effects of specific Setd2 knockout on the proliferation and apoptosis of dental germ mesenchymal cells; immunofluorescence (IF) staining was conducted to observe the impact of Setd2 knockout on the trimethylation of lysine 36 on histone 3 (H3K36me3). Results PCR-based genotyping showed that the experimental group presented a single band (266 bp) for the Setd2flox/flox homozygote and a characteristic band for Wnt1Cre, while the control group only showed a single band (266 bp) for the Setd2flox/flox homozygote. IHC staining confirmed the successful knockout of Setd2 in dental germ mesenchymal cells of the experimental group; HE staining and subrenal culture demonstrated that specific knockout of Setd2 in the experimental group led to reduced size of tooth germs and increased condensation of mesenchymal cells at E15.5 and E18.5 (E15.5, P < 0.05; E18.5, P < 0.01); Ki67 staining showed no statistically significant effect on the proportion of division of dental germ mesenchymal cells between the experimental and control groups at E13.5 and E15.5 (E13.5, P = 0.694; E15.5, P = 0.503); the TUNEL assay demonstrated increased apoptosis of dental germ mesenchymal cells in the experimental group at both E13.5 and E15.5 (P < 0.001); IF staining revealed the absence of H3K36me3 modification in the dental germ mesenchymal cells of the experimental group across E13.5, E15.5, and E18.5 (P < 0.000 1). Conclusion Specific knockout of Setd2 in dental germ mesenchymal cells leads to increased cell apoptosis by impairing H3K36me3 modification, resulting in early developmental defects in mouse teeth characterized by reduced tooth germ volume.
Objective To investigate the ability of different concentrations of piceatannol (PIC) solution to biomodify decalcified dentin matrices in primary teeth, thereby providing a theoretical basis for improving the durability of resin-dentin bonding. Methods This study was approved by the Medical Ethics Committee of the institution. Molecular docking was performed to predict the interaction effects of PIC with type I collagen and matrix metalloproteinases (MMPs) in dentin. A total of 124 clinically extracted intact primary molars were selected due to retention; of these, 76 were prepared into 60 completely decalcified dentin beams and 24 dentin slices. The 60 beams were equally allocated for dry mass loss and swelling ratio testing (30 beams each). For both experiments, the beams were randomly divided into five groups (n = 6): a control group, 5% glutaraldehyde group, and 2.5, 5, and 10 mg/mL PIC solution groups. This was to evaluate the anti-enzymatic hydrolytic properties and mechanical performance of type I collagen. Of the 24 slices, 15 were assigned to the aforementioned five groups (n = 3) for Fourier-transform infrared spectroscopy (FTIR) to explore the cross-linking mechanism. The remaining nine slices were randomly divided into three groups (n = 3): distilled water group A (SEM examination prior to enzymatic hydrolysis), distilled water group B (SEM examination after enzymatic hydrolysis), and a 10 mg/mL PIC solution group (SEM examination after treatment with 10 mg/mL PIC and subsequent enzymatic hydrolysis). This was to evaluate the cross-linking effect on demineralized dentin collagen. The remaining 48 molars were fabricated into bonding specimens and randomly divided into four groups (n = 12): a control group (distilled water group) and 2.5, 5, and 10 mg/mL PIC groups. Immediate and aged shear bond strength (SBS) were measured, and failure modes were observed under a stereomicroscope to investigate the impact of different PIC concentrations on the bonding durability of primary tooth dentin. Results Molecular docking revealed strong binding activity between PIC and type I collagen/MMPs via hydrogen bonds, electrostatic potential, and hydrophobic forces; the FTIR results confirmed hydrogen bond formation. In the dry mass loss test, mass loss rates in the 2.5, 5, and 10 mg/mL PIC groups were significantly lower than that in the control group (P < 0.05), with the 10 mg/mL PIC group showing the most optimized cross-linking effect. Swelling tests indicated that all three PIC concentrations reduced the swelling ratio of the demineralized matrix, effectively improving its mechanical properties. SEM showed that collagen from the 10 mg/mL PIC group retained its natural three-dimensional network post-enzymolysis, contrasting sharply with the disintegrated collagen in the enzymolyzed distilled water group B but resembling the morphology of the non-enzymolyzed distilled water group A. SBS results demonstrated that the 10 mg/mL PIC group exhibited significantly higher bond strengths than the control group in both the immediate and aged tests (P < 0.05); immediate SBS in the 10 mg/mL PIC group was also significantly greater than that in the 2.5 mg/mL PIC group (P < 0.05), while no other intergroup differences were found (P > 0.05). Failure mode analysis indicated predominantly mixed fractures, with the proportion of interfacial fractures decreasing as PIC concentration increased compared with the control group. Conclusion A 10 mg/mL PIC solution can effectively cross-link decalcified dentin matrices in primary teeth, enhancing the anti-enzymatic hydrolytic capacity and mechanical properties during clinical operation, thereby promoting bond strength and interface stability, which promises to improve the long-term durability of resin-dentin bonding.
Objective To compare the effects of immediate versus delayed post-space preparation on the bond strength of fiber posts and the fracture resistance of roots after root canal obturation using iRoot SP and the single-cone technique, and to provide an experimental basis for the selection of the timing of clinical post-space preparation. Methods This study was approved by the Medical Ethics Committee of the institution, and written informed consent was obtained from all participants. Seventy-two extracted human single-rooted premolars were randomly divided into two groups (n = 36 each): the immediate post-space preparation group (post-space preparation performed immediately after root canal obturation) and the delayed post-space preparation group (post-space preparation performed 1 week after root canal obturation). Cleanliness of the root canal walls was assessed with a dental microscope after preparation in both groups; the ultrastructural characteristics of the dentinal surface were examined via scanning electron microscopy; the fracture resistance of roots was measured with root fracture resistance tests; the bond strength of the fiber posts was measured with the thin-slice push-out test; and the bond failure modes were observed and analyzed under a stereomicroscope. Results Under dental microscopy, the dentin surface of the immediate post-space preparation group appeared cleaner than that of the delayed post-space preparation group. Scanning electron microscopy revealed that most dentinal tubules remained open in the immediate post-space preparation group, while the tubules in the delayed post-space preparation group showed incomplete patency. The fracture resistance of the immediate post-space preparation group was (2 872 ± 241.5) N and that of the delayed post-space preparation group was (2 934 ± 353.1) N, with no statistically significant difference (t = -0.328, P = 0.751). The push-out bond strength of the immediate post-space preparation group (10.310 ± 2.907) MPa was significantly higher than that of the delayed post-space preparation group (7.917 ± 2.429) MPa, with a statistically significant difference (t = 4.457, P < 0.001). Analysis of failure modes showed that adhesive-to-dental interface failure was the predominant mode in both groups. Conclusion Following root canal obturation with iRoot SP using the single-cone technique, immediate post-space preparation yields superior fiber post bond strength compared to delayed post-space preparation, without compromising root fracture resistance.
Objective To analyze the clinical characteristics and management strategies of metronidazole-associated Stevens-Johnson syndrome (SJS), and to provide a clinical basis for medication safety during the oral perioperative period. Methods The study adhered to the tenets of the Declaration of Helsinki and was approved by the Ethics Committee of Stomatological Hospital of Xi'an Jiaotong University. A retrospective analysis was conducted on a case of SJS following mandibular impacted tooth extraction, for which the patient had taken metronidazole. Additionally, a literature review was performed by searching databases including China National Knowledge Infrastructure, Wanfang, PubMed, and Web of Science to identify reported cases of metronidazole-associated SJS. Demographic features, medication regimens, latency periods, clinical signs, interventions, and prognosis were analyzed. Results The patient presented with lip swelling, extensive erosion and ulceration of the oral mucosa, and severe odynophagia. Scattered erythematous macules and bullae were observed on the trunk and extremities, with a positive Nikolsky sign. Additionally, there was erosion of the perineal skin and glans penis mucosa, along with skin desquamation of the scrotum. The patient with SJS was managed in the hospital by discontinuing metronidazole and administering sequential treatments, including glucocorticoids, immunomodulators, intravenous immunoglobulin, and plasma exchange. The condition gradually improved; after a 14-month follow-up, only mild dry eye remained, with no significant scarring of the skin or mucosa. However, delayed recognition of early warning signs resulted in delayed drug withdrawal and intervention. The literature review identified 6 additional cases (3 males, 3 females) with a median age of 45.5 years (range 31-61). Indications for metronidazole included postoperative sepsis prophylaxis after duodenal ulcer perforation repair, digestive system infections, mucosal diseases, pelvic inflammatory disease, septic cellulitis with pneumonia, and gingivitis. Administration routes comprised oral (n = 2), intravenous (n = 3), and topical (n = 1). The latency period from drug administration to onset ranged from 0.25 to 7 days (median 4 days). All of the cases presented with oral mucosal erosion, and a positive Nikolsky’s sign was noted for five patients. Discontinuation of the causative drug was the cornerstone of treatment, supplemented by immunomodulatory therapy, symptomatic support, and multidisciplinary collaboration. Prognoses varied significantly: among the four patients treated with “drug withdrawal + glucocorticoids + supportive care,” three recovered fully and one improved; among the two patients receiving “drug withdrawal + simple supportive care,” one recovered and one died. Conclusion Although metronidazole-associated SJS is rare, it progresses rapidly and frequently involves oral mucosal damage, typically occurring within one week of administering the medication. Early drug withdrawal and prompt initiation of glucocorticoid therapy can improve prognosis. During the oral perioperative period, strict adherence to metronidazole indications, enhanced monitoring for early warning symptoms, and the establishment of a multidisciplinary collaborative diagnosis and treatment model are essential to minimize the risk of severe adverse drug reactions.
Autotransplantation of teeth (ATT) is a surgical technique that involves transplanting a non-functional tooth (donor tooth) within the oral cavity to an edentulous area (recipient site). This procedure not only demonstrates reliable long-term success and survival rates but also possesses unique osteoinductive capacity and soft tissue preservation advantages, making it particularly suitable for the restoration of dental defects in adolescents. However, ATT is highly technique-sensitive, and its successful implementation depends on the operator’s comprehensive mastery of multidisciplinary knowledge, including alveolar surgery, periodontology, endodontics, prosthodontics, and orthodontics, as well as the precise design and execution of personalized surgical plans. Preoperative systematic evaluation is required to assess the root development stage of the donor tooth, the bone volume condition of the recipient site, and the compatibility between the donor tooth and the recipient site. For teeth with an open apex, pulpal healing through revascularization is often achievable with a high success rate, whereas those with a closed apex typically require root canal treatment 2-4 weeks postoperatively to minimize complications. Utilizing cone beam computed tomography, intraoral scanning, and virtual surgical planning enables accurate assessment of donor-recipient matching and the design of the transplantation plan. Intraoperatively, careful attention must be paid to minimizing tissue trauma through precise planning and gentle manipulation, strictly limiting the extra-oral time of the donor tooth to within 15 min, and maintaining the root surface moist at all times to protect the periodontal ligament and improve surgical outcomes. The application of tools, such as 3D-printed personalized surgical guides, donor tooth replicas, and customized osteotomes, has enhanced the precision of socket preparation. Further, emerging technologies, such as dynamic navigation, surgical robotics, and artificial intelligence, have also demonstrated promising potential in the field of ATT.
N-acetylcysteine (NAC) is an acetylated derivative of cysteine that exerts multiple biological activities, including antioxidant, anti-inflammatory, antimicrobial, and mucolytic effects, and has been widely used clinically for the treatment of respiratory diseases. NAC not only directly scavenges reactive oxygen and nitrogen species and strengthens endogenous antioxidant defenses by promoting glutathione synthesis but also modulates immune responses and suppresses inflammatory signaling pathways such as nuclear factor kappa B, thereby attenuating inflammation. In addition, NAC disrupts biofilm architecture by cleaving disulfide bonds, reduces microbial virulence, and enhances the penetration of antimicrobial agents, conferring robust antibacterial and antibiofilm activities. The initiation and progression of oral diseases—including dental caries, periodontal disease, pulpal-periapical disease, and infectious oral mucositis—are closely associated with pathogenic infection, oxidative stress, and dysregulated immune-inflammatory responses. NAC can inhibit Streptococcus mutans adhesion and biofilm formation, thereby reducing cariogenic virulence; mitigate periodontal tissue destruction through antimicrobial, anti-inflammatory, and antioxidant actions, and may modulate bone metabolism; enhance the clearance of Enterococcus faecalis biofilms and improve the efficacy of antimicrobial therapy; and inhibit the growth and hyphal formation of Candida albicans. Collectively, NAC is emerging as a promising agent for the prevention and treatment of oral infectious diseases. This review systematically summarizes the major bioactivities of NAC, its mechanistic actions in oral infectious diseases, and its therapeutic prospects, with the aim of providing a theoretical basis for future basic and clinical investigations.
The complete functional regeneration of periodontal tissues—specifically, the simultaneous reconstruction of alveolar bone, cementum, and periodontal ligament—represents a major challenge in oral regenerative medicine. Dental-derived mesenchymal stem cells (DMSCs) are regarded as ideal seed cells for achieving this goal due to their multi-lineage differentiation potential and immunomodulatory properties. As a cell carrier, hydrogels offer the key advantage of mimicking the extracellular matrix through precisely tunable physicochemical properties (e.g., matrix stiffness, topological structure, degradation kinetics), thereby constructing a mechanical and biochemical microenvironment that actively directs stem cell fate. This review summarizes the application and research progress of DMSC-laden hydrogels in periodontal tissue repair. We first analyze the material characteristics of different hydrogel systems, and then elaborate on the specific molecular mechanisms by which hydrogels regulate DMSCs’ differentiation through mechanical properties such as matrix stiffness: stiff hydrogels drive osteogenic differentiation by activating the integrin-focal adhesion kinase (FAK)-Akt/mechanistic target of rapamycin (mTOR) signaling axis; inducing cytoskeletal remodeling, and promoting dephosphorylation and nuclear translocation of Yes-associated protein (YAP)/transcriptional co-activator with PDZ-binding motif (TAZ) to initiate the transcription of osteogenesis-related genes; and stabilizing β-catenin and activating the Wnt/β-catenin signaling pathway, upregulating the expression of key osteogenic transcription factors including Runt-related transcription factor 2 (Runx2) and Osterix. Furthermore, as programmed controlled-release carriers for bioactive factors, hydrogels selectively activate Smad signaling subtypes—pro-osteogenic factors specifically activate the Smad1/5/8 pathway, whereas factors promoting periodontal ligament formation activate the Smad2/3 pathway—thereby achieving precise, directed differentiation of DMSCs toward osteogenic, cementogenic, or fibroblastic lineages. Current key scientific issues in this field include the dynamic adaptation of hydrogel properties during regeneration, stable control of the complex oral microenvironment (e.g., microbes, mechanical forces, inflammation), strategies for efficient directional differentiation of stem cells, and feasibility of clinical translation. Future research directions should focus on developing smart-responsive hydrogels, constructing personalized biomimetic scaffolds combined with three-dimensional bioprinting technology, and designing composite material systems with immunomodulatory functions, aiming ultimately to achieve integrated structural and functional regeneration of periodontal tissue.
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