Lei Dou

Objective: The aim of this study was to evaluate the applicative potential of 3D‐printed teeth, designed from real clinical cases, in endodontic specialty training. Methods: The study collected radiological data from clinical cases and performed 3D reconstruction. Through the data of 3D reconstruction, two 3D‐printed materials were used to fabricate personalized, full‐size, resin tooth models. These models were assigned to endodontic specialty trainees for root canal therapy practice in the dental simulator. A questionnaire was designed to evaluate trainees' perceptions of the similarity between 3D‐printed tooth models and natural teeth, using a 5‐point scale (1 = extremely dissimilar, 5 = extremely similar). Results: The results indicated that the 3D‐printed tooth models accurately replicated the anatomical shape and root canal morphology of natural teeth, closely resembling real clinical cases. Trainees perceived the instructional value of the 3D‐printed models as moderately similar to that of natural teeth. However, the hardness of 3D‐printed models varied depending on the material used. Trainees reported a noticeable difference in handling perception between all resin tooth models and natural teeth during operative procedures. Conclusion: Personalized 3D‐printed tooth models—designed from real clinical cases with high anatomical accuracy and scalable production potential—demonstrate significant promise as specialized teaching aids for endodontic root canal therapy training. These models offer endodontic trainees the invaluable opportunity to practice on simulations of typical or complex clinical scenarios.

Aim: This study aimed to develop an injectable thermo‐responsive composite paste based on digested dentine matrix extract (DDME) for dentine regeneration, with potential applications in vital pulp therapy. Methodology: An injectable PLGA–PEG–PLGA/DDME paste was developed and characterized using FTIR. The injectability and self‐curing behavior of the composite were evaluated. Its biocompatibility and odontogenic potential were assessed in vitro using human dental pulp cells (hDPCs). Dentine‐forming capacity was investigated in an in situ rat model. The effect of the paste on protein expression in hDPCs was examined by label‐free proteomic analysis, and the underlying mechanism of DDME‐induced odontogenesis was screened. Data were analyzed using Student's t‐test and one‐way analysis of variance. Results: The PLGA–PEG–PLGA/DDME paste exhibited excellent injectability and temperature‐dependent self‐curing. Rheological analysis confirmed shear‐thinning behaviour and enhanced viscoelastic properties compared to Water/DDME controls. PLGA–PEG–PLGA significantly improved the handling characteristics of DDME while preserving its bioactivity. In vitro, the paste supported human dental pulp cell viability, migration and odontogenic differentiation, upregulating RUNX2, DMP‐1, DSPP and ALP, and enhancing mineralized nodule formation. In situ evaluation in a rat dentine defect model demonstrated that the paste promoted the formation of dentine bridges. Proteomic analysis revealed mTOR signalling as a key pathway, and inhibition experiments with rapamycin confirmed its role in mediating DDME‐induced odontogenesis. Conclusions: The PLGA‐PEG‐PLGA/DDME composite paste is a promising injectable biomaterial for dentine regeneration, with mTOR modulation offering a potential strategy to optimize outcomes.

To explore the spatial distribution of the neurovascular network following pulp exposure using tissue clearing technology and three-dimensional imaging. An animal model with dental pulp exposure was established in maxillary molars of Sprague–Dawley rats using a round bur under water cooling. Histological evaluation was performed at various time points, and samples at 24 h postoperatively was selected for tissue clearing and whole-mount immunofluorescence staining using markers for blood vessels, nerves, lymphatics, and mesenchymal stem cells. Three-dimensional images were captured with a light-sheet microscope. Three-dimensional imaging revealed the spatial arrangement of nerves, blood vessels, and lymphatic vessels, as well as the relative positions of sympathetic and sensory nerves in the maxilla. The neurovascular network structure in pulp-exposed molars showed significant alterations compared to healthy molars. Additionally, nerves passing through lateral canals were visualized in three-dimensional space. Numerous STRO-1-positive cells were identified in the maxilla, although their distribution lacked a defined spatial pattern. This study sheds light on the three-dimensional architecture of vascular, neural, and lymphatic networks in dental pulp and surrounding tissues under healthy and pathological conditions. Tissue clearing proves to be a valuable technique for visualizing the spatial organization of dental pulp tissue in physiological and pathological states.

Aim: To establish a 3D model for screening the biocompatibility of dental materials/drugs on dental pulp cells and tissue.Methodology: Human dental pulp cells (hDPC) and endothelial cells (EC) were mixed with or without human dental pulp derived extracellular matrix (hDP‐ECM) according to several protocols and cultured in 3D plates to fabricate 3D organoids. Cell viability and proliferation in organoids were evaluated using Live/Dead cell viability assay and ATPase assay. Organoids were fixed, cut and stained with a H&E staining kit. The expressions of DSPP, DMP‐1, CD31, vWF and COL1A in 3D organoids were evaluated using immunofluorescence. To assess the feasibility of 3D organoids on drug/material toxicity screening, the organoids were treated with lipopolysaccharides (LPS) or iRoot BP. Then, cell viability and apoptosis were assessed. The expressions of IL‐6, TNF‐α, and IL‐1β were compared in LPS‐treated and non‐treated organoids. Alizarin Red S staining was used to evaluate calcium deposit formation in organoids. Data were analysed using one‐way anova followed by Tukey's post hoc comparison.Results: The 3D spheres/organoids were formed at day 1 or day 2. Cells in 3D organoids maintained a high viability rate and low proliferation activity. The level of CD31 increased significantly (p < .05) when EC were added to coculture with hDPC. The expressions of odontogenesis‐associated proteins (DSPP, COL1A) upregulated (p < .05) with the addition of hDP‐ECM. Level of IL‐6 expression and rates of dead and apoptotic cells in 3D organoids were increased significantly (p < .05) in response to LPS. Calcium deposit formation was observed in iRoot BP‐treated organoids.Conclusions: Coculture of hDPC and EC in the presence of hDP‐ECM formed functional dental pulp organoids. The experimental model provides an alternative tool for toxicity screening of dental pulp capping agents and dental pulp regeneration research.

This study investigated the safety of a novel cell-labeling technology with mKATE and Renilla reniformis luciferase (mKATE-renLUC) and assessed the efficacy on tracking implanted human placental stromal cells (PSC) in an erectile dysfunction (ED) animal model. Human PSC were labeled with mKATE-renLUC using a lentivirus. Cell viability, apoptosis, proliferation, migration, surface marker expression and differentiation potential of the labeled PSC were evaluated and compared with non-labeled PSC. The paracrine profile of labeled cells was examined using an angiogenesis protein array. The brightness and duration of labeled cells with different densities were evaluated. An ED rat model was established and labeled PSC were injected into cavernosal tissue of the penis. The migration and distribution of transplanted PSC were monitored using an IVIS imaging system in real time. Implanted PSC were identified in isolated tissues via detection of mKATE fluorescence. The cell viability, morphology, proliferation, migration, surface marker expression and differentiation potential of mKATE-renLUC-labeled PSC were similar to those of non-labeled cells in vitro (no statistical difference p>0.05). Similar expressions of trophic factors were found between labeled and non-labeled PSC. The migration and distribution of PSC expressing renLUC were tracked in vivo using IVIS imaging system. mKATE-positive PSC were detected in penile, kidney, prostate and hepatic tissues using histological methods. This labeling technology provides a safe and effective cell-tracking approach with a brighter fluorophore and codon-optimized luciferase.

The aim is to investigate the prevalence of dental anxiety and its association with pain and other related factors in adult patients with irreversible pulpitis. One hundred and thirty patients with irreversible pulpitis were included in this cross-sectional study. Participants were asked to fill out an information table and a battery of questionnaires to assess their level of dental anxiety, pain at their first and most recent dental experience, and pain intensity before/during the present endodontic treatment. The level of anxiety that participants displayed during the present treatment was also evaluated by the dentists using an anxiety rating scale. Data were analyzed by t-test, ANOVA, and Spearman correlation tests. 83.1% of participants suffered from moderate or high dental anxiety, and 16.2% met criteria for specific phobia. Subjects who had higher MDAS scores were more likely to postpone their dental visits (P < 0.05). Subjects who had bad experiences at their most recent dental visit were more anxious (P < 0.05). Pain at the most recent dental visit (P < 0.01) or before the present dental visit (P < 0.05) was important factor correlating with dental anxiety among participants. Notably, 36.2% of participants displayed moderate or severe anxiety during this present visit for endodontic treatment based on dentist’s judgement. A high percentage of people with irreversible pulpitis suffer from dental anxiety. Pain at the most recent dental visit and during endodontic treatment have strongly positive association with dental anxiety. Effective pain control in endodontics is beneficial to manage the anxiety.