Three-dimensionally printed implant surgical guide-related experience, knowledge, attitude, and professional behaviors among 2028 dentists in China: A cross-sectional study.

STATEMENT OF PROBLEM: Research on the current place of 3-dimensionally printed implant surgical guides (3D-ISGs) among practicing dentists worldwide is lacking, with little research focused on dentists' experience, knowledge, attitude, or professional behavior related to 3D-ISG or on the main obstacle to adoption. PURPOSE: The purpose of this cross-sectional study was to identify the adoption of 3D-ISG in dental practice in China and to determine factors that influence its further application and dentists' attitudes and willingness. MATERIAL AND METHODS: Semistructured questionnaires were sent to a sample of Chinese dentists composed of users and nonusers of 3D-ISG. The questionnaires were displayed and distributed through a professional online survey system (http://www.wjx.cn) and a social media platform (WeChat). The responses were analyzed with multivariable generalized equations, and the effect of various demographic variables was determined, including dentist experience, academic degree, and type of practice (public or private). RESULTS: A total of 2028 valid questionnaires were collected. In dental practice, 39.3% of the respondents used 3D-ISG. Respondents with a PhD (62.4%) used the 3D-ISG more than twice as frequently as respondents with a junior college degree or below (31.8%). The majority of the members of implantology departments (81.7%) applied 3D-ISG, but doctors in other departments used it at a rate of less than half. The 3D-ISG was most frequently used in the maxillary anterior area (78.4%), followed by the edentulous maxilla and mandible (61.0% and 60.5%, respectively). The main barriers were high initial cost, complex and time-consuming digital design, and lack of expertise in the proper use of 3D-ISG. CONCLUSIONS: Most dentists did not use 3D-ISG in dental practice. The 3D-ISG application rate was significantly associated with sex, academic degree, years of dental practice, department, monthly income, and type of healthcare facility. To improve the popularity of 3D-ISG, particularly among dentists without advanced degrees, it would be important to optimize the digital design software program and provide sufficient training.

Effect of universal adhesive and silane pretreatment on bond durability of metal brackets to dental glass ceramics.

This study aimed to investigate the effect of universal adhesive and silane pretreatment on the bond durability of metal brackets to dental glass ceramics. Eighty lithium disilicate glass ceramic specimens were randomly assigned to one of four groups (n = 20) defined by the pretreatment and adhesive used: (i) Adper Single Bond 2; (ii) silane + Adper Single Bond 2; (iii) Single Bond Universal; and (iv) silane +Single Bond Universal. Maxillary central incisor metal brackets were bonded on the ceramic surfaces with resin composite. A shear bond strength test was conducted after 24 h of water storage and after 10,000 thermocycles. Adhesive remnant index scoring and field-emission scanning electron microscopy were performed to determine adhesives remaining on the ceramic surfaces and the ceramic ultrastructure following bracket debonding, respectively. After 10,000 thermocycles, specimens treated with Single Bond Universal preserved an appropriate bond strength between brackets and glass ceramics and showed minimum ceramic surface damage following bracket debonding, which was not the case in the other three groups. The application of a silane-containing universal adhesive without silane pretreatment achieves adequate durability of the bond of metal brackets to dental glass ceramics and allows safe debonding, which may aid in optimizing the effectiveness for orthodontic treatment.

Deep learning detection of prostate cancer recurrence with 18F-FACBC (fluciclovine, Axumin®) positron emission tomography.

PURPOSE: To evaluate the performance of deep learning (DL) classifiers in discriminating normal and abnormal 18F-FACBC (fluciclovine, Axumin®) PET scans based on the presence of tumor recurrence and/or metastases in patients with prostate cancer (PC) and biochemical recurrence (BCR). METHODS: A total of 251 consecutive 18F-fluciclovine PET scans were acquired between September 2017 and June 2019 in 233 PC patients with BCR (18 patients had 2 scans). PET images were labeled as normal or abnormal using clinical reports as the ground truth. Convolutional neural network (CNN) models were trained using two different architectures, a 2D-CNN (ResNet-50) using single slices (slice-based approach) and the same 2D-CNN and a 3D-CNN (ResNet-14) using a hundred slices per PET image (case-based approach). Models' performances were evaluated on independent test datasets. RESULTS: For the 2D-CNN slice-based approach, 6800 and 536 slices were used for training and test datasets, respectively. The sensitivity and specificity of this model were 90.7% and 95.1%, and the area under the curve (AUC) of receiver operating characteristic curve was 0.971 (p < 0.001). For the case-based approaches using both 2D-CNN and 3D-CNN architectures, a training dataset of 100 images and a test dataset of 28 images were randomly allocated. The sensitivity, specificity, and AUC to discriminate abnormal images by the 2D-CNN and 3D-CNN case-based approaches were 85.7%, 71.4%, and 0.750 (p = 0.013) and 71.4%, 71.4%, and 0.699 (p = 0.053), respectively. CONCLUSION: DL accurately classifies abnormal 18F-fluciclovine PET images of the pelvis in patients with BCR of PC. A DL classifier using single slice prediction had superior performance over case-based prediction.

In vitro remineralization of enamel white spot lesions with a carrier-based amorphous calcium phosphate delivery system.

OBJECTIVES: To achieve in vitro remineralization of enamel white spot lesions (WSLs) via a mesoporous delivery system of amorphous calcium phosphate (ACP) precursors. MATERIALS AND METHODS: Amine-functionalized expanded pore mesoporous silica (aMSN) was loaded with polyacrylic acid-stabilized amorphous calcium phosphate (PAA-ACP) to develop a carrier-based delivery system (PAA-ACP@aMSN). Thirty-six artificial WSLs samples were created and randomly assigned to three treatments: artificial saliva solution (negative control, n = 12), casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) slurry (n = 12), and PAA-ACP@aMSN slurry (n = 12). Surface microhardness, Raman intensity, and color were measured before/after artificial demineralization and after remineralization treatments to evaluate the remineralization level of each sample. SEM images were taken on the surface and cross-section of samples to observe microstructure changes. RESULTS: The surface microhardness recovery ratio (%SMHRR), Raman intensity change ratio (%ICR), and color recovery ratio (%CRR) were not significantly different between CPP-ACP and PAA-ACP@aMSN groups (P > 0.05), but both of them had significantly higher %SMHRR, %ICR, and %CRR values than negative control (P < 0.01). SEM images showed that apparent enamel prism imprints and inter-prism gaps in negative control were masked by mineral deposition in the PAA-ACP@aMSN and CPP-ACP groups. CONCLUSIONS: PAA-ACP@aMSN has an ability to remineralize enamel WSLs. CLINICAL RELEVANCE: The carrier-based amorphous calcium phosphate delivery system has great potential to serve as a remineralizing agent for the treatment of WSLs.

Current Enamel Remineralization Therapies Have Limited Effects on Postorthodontic White Spot Lesions.

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION: Enamel remineralization therapies for treating postorthodontic white spot lesions: a systematic review. Fernández-Ferrer L, Vicente-Ruíz M, García-Sanz V, Montiel-Company JM, Paredes-Gallardo V, Almerich-Silla JM, Bellot-Arcís C. J Am Dent Assoc 2018; 149(9):778-86.e2. SOURCE OF FUNDING: No financial support was reported. TYPE OF STUDY/DESIGN: Systematic review.

Pannexin3 inhibits TNF-α-induced inflammatory response by suppressing NF-κB signalling pathway in human dental pulp cells.

Human dental pulp cells (HDPCs) play a crucial role in dental pulp inflammation. Pannexin 3 (Panx3), a member of Panxs (Pannexins), has been recently found to be involved in inflammation. However, the mechanism of Panx3 in human dental pulp inflammation remains unclear. In this study, the role of Panx3 in inflammatory response was firstly explored, and its potential mechanism was proposed. Immunohistochemical staining showed that Panx3 levels were diminished in inflamed human and rat dental pulp tissues. In vitro, Panx3 expression was significantly down-regulated in HDPCs following a TNF-α challenge in a concentration-dependent way, which reached the lowest level at 10 ng/ml of TNF-α. Such decrease could be reversed by MG132, a proteasome inhibitor. Unlike MG132, BAY 11-7082, a NF-κB inhibitor, even reinforced the inhibitory effect of TNF-α. Quantitative real-time PCR (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA) were used to investigate the role of Panx3 in inflammatory response of HDPCs. TNF-α-induced pro-inflammatory cytokines, interleukin (IL)-1ß and IL-6, were significantly lessened when Panx3 was overexpressed in HDPCs. Conversely, Panx3 knockdown exacerbated the expression of pro-inflammatory cytokines. Moreover, Western blot, dual-luciferase reporter assay, immunofluorescence staining, qRT-PCR and ELISA results showed that Panx3 participated in dental pulp inflammation in a NF-κB-dependent manner. These findings suggested that Panx3 has a defensive role in dental pulp inflammation, serving as a potential target to be exploited for the intervention of human dental pulp inflammation.

Effect of silane pretreatment on the immediate bonding of universal adhesives to computer-aided design/computer-aided manufacturing lithium disilicate glass ceramics.

The aim of this study was to investigate the effect of silane pretreatment on the universal adhesive bonding between lithium disilicate glass ceramic and composite resin. IPS e.max ceramic blocks etched with hydrofluoric acid were randomly assigned to one of eight groups treated with one of four universal adhesives (two silane-free adhesives and two silane-containing adhesives), each with or without silane pretreatment. Bonded specimens were stored in water for 24 h. The shear bond strength (SBS) of the ceramic-resin interface was measured to evaluate bond strength, and the debonded interface after the SBS test was analysed using field-emission scanning electron microscopy to determine failure mode. Light microscopy was performed to analyse microleakage and marginal sealing ability. Silane pretreatment significantly and positively influenced SBS and marginal sealing ability. For all the universal adhesive groups, SBS increased and the percentage of microleakage decreased after the pretreatment. Without the pretreatment, SBS and the percentage of microleakage were not significantly different between the silane-containing universal adhesive groups and the silane-free groups. Cohesive failure was the main fracture pattern. The results suggest that additional silane pretreatment can effectively improve the bonding strength and marginal sealing of adhesives to lithium disilicate glass ceramics. The bonding performance of silane-containing universal adhesives without pretreatment is similar to that of silane-free adhesives.

Dimethyl Sulfoxide Wet-bonding Technique May Improve the Quality of Dentin Bonding.

PURPOSE: To investigate the effect of the dimethyl-sulfoxide wet-bonding technique on composite-dentin bonds and to explore its potential mechanism. MATERIALS AND METHODS: Thirty human third molars were segmented, ground, etched, and randomly divided into three groups according to the following pretreatments: 1. water; 2. ethanol; 3. 50% (v/v) dimethyl sulfoxide (DMSO). Then, Single Bond 2 was applied and composite buildups were constructed. After 24 h of water storage or 10,000 cycles of thermocycling, the microtensile bond strength (MTBS) and nanoleakage were measured. Contact angle measurement, Masson's trichrome staining, and in situ zymography were used to explore the possible action mechanism of DMSO on adhesive-dentin interfaces. RESULTS: DMSO pretreatment prevented the decline of thermocycled MTBS (p < 0.05) without affecting the immediate MTBS (p > 0.05) compared to the water wet-bonded group. Nanoleakage expression in the thermocycled DMSO wet-bonded group was also less than that in the thermocycled water-wet group (p < 0.05). Moreover, DMSO decreased the contact angle of the dentin surfaces (p < 0.05), reduced the amount of collagen exposure (p < 0.05), and decreased the collagenolytic activity in the hybrid layer (p < 0.05). CONCLUSION: The 50% DMSO pretreatment was effective in increasing the wettability of the etched dentin surface, promoting the penetration of the adhesive monomer, and enhancing the stability of the dentin collagen at the adhesive- dentin interface. All these changes may lead to higher quality dentin bonds, suggesting that DMSO wet bonding is a viable alternative to improve the durability of dentin bonding.

Effects of Chlorhexidine-Encapsulated Mesoporous Silica Nanoparticles on the Anti-Biofilm and Mechanical Properties of Glass Ionomer Cement.

One of the primary causes for the failure of glass ionomer cement (GIC) is secondary caries. To enhance the anti-microbial performance of GIC without affecting its mechanical properties, chlorhexidine (CHX) was encapsulated in expanded-pore mesoporous silica nanoparticles (pMSN) to synthesize CHX@pMSN. CHX@pMSN was added at three mass fractions (1%, 5%, and 10% (w/w)) to GIC powder as the experimental groups. Pure GIC was set as the control group. The mechanical and anti-biofilm properties of GIC from each group were tested. The results demonstrated that CHX was successfully encapsulated on/into pMSN, and the encapsulating efficiency of CHX was 44.62% in CHX@pMSN. The anti-biofilm ability was significantly enhanced in all experimental groups (p < 0.001) compared with that in the control group. CHX was continuously released, and anti-biofilm ability was maintained up to 30 days. In addition, the mechanical properties (compressive strength, surface hardness, elastic modulus, water sorption, and solubility) of 1% (w/w) group were maintained compared with those in the control group (p > 0.05). In conclusion, adding 1% (w/w) CHX@pMSN to GIC led to conspicuous anti-biofilm ability and had no adverse effect on the mechanical properties of this restorative material. This study proposes a new strategy for preventing secondary caries by using CHX@pMSN-modified GIC.

Optimization of direct currents to enhance dentine bonding of simplified one-step adhesive.

The aim of this study was to investigate the effects of different direct current intensities on dentine bonding effectiveness of Clearfil S(3) Bond and on cell viability of human dental pulp cells (HDPCs). Thirty-five-third molars were sectioned and ground to provide flat surfaces. Clearfil S(3) Bond was applied under different current conditions for 30 s and then resin composite was built up. Specimens were processed for microtensile bond strength (µTBS) testing and for nanoleakage investigation using scanning electron microscopy. Primary HDPCs isolated from premolars were stimulated with different intensities of electric current for 30 s. Then, cell viability was tested using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Specimens bonded with application of electrical current intensities of 50, 60, 70, and 90 µA exhibited a significant increase in immediate µTBS compared with all other groups. Bonded interfaces prepared using electrically assisted current application showed reduced interfacial nanoleakage upon scanning electron microscopy. Electric current application, from 20 to 70 µA, had no effect on the viability of HDPCs. This study provides further evidence for its future clinical use.

Purification and characterization of a novel alkaline ß-1,3-1,4-glucanase (lichenase) from thermophilic fungus Malbranchea cinnamomea.

A novel alkaline ß-1,3-1,4-glucanase (McLic1) from a thermophilic fungus, Malbranchea cinnamomea, was purified and biochemically characterized. McLic1 was purified to homogeneity with a purification fold of 3.1 and a recovery yield of 3.7 %. The purified enzyme was most active at pH 10.0 and 55 °C, and exhibited a wide range of pH stability (pH 4.0-10.0). McLic1 displayed strict substrate specificity for barley ß-glucan, oat ß-glucan and lichenan, but did not show activity towards other tested polysaccharides and synthetic p-nitrophenyl derivates, suggesting that it is a specific ß-1,3-1,4-glucanase. The K m values for barley ß-glucan, oat ß-glucan and lichenan were determined to be 0.69, 1.11 and 0.63 mg mL(-1), respectively. Moreover, the enzyme was stable in various non ionic surfactants, oxidizing agents and several commercial detergents. Thus, the alkaline ß-1,3-1,4-glucanase may have potential in industrial applications, such as detergent, paper and pulp industries.

A novel and efficient electrochemiluminescence sensing strategy for the determination of trimethylamine oxide in seafood.

A novel and efficient electrochemiluminescence (ECL) sensing strategy and a solid-state ECL sensor was proposed to detect trimethylamine oxide (TMAO), which is widely presented in marine species and has important physiological functions. TMAO was reduced by Fe(II)-EDTA complex to trimethylamine, acting as coreactant, to amplify the ECL response of the Ru (bpy)32+ system. To improve the detection sensitivity and efficiency, a robust solid-state ECL probe was prepared and a flow injection ECL detection system was established with a specially designed flow ECL unit, under the excitation of stepping pulse potentials. Under optimized experimental conditions, the developed ECL sensor worked well for TMAO detection in a wide linear range of 10.00 µM to 1.00 mM with a limit of detection of 3.41 µM. It was successfully applied to determine TMAO in various species of seafood samples. This work provides a promising strategy for TMAO detection.

Advances in ceramics for tooth repair: From bench to chairside.

OBJECTIVES: To give a comprehensive review of advancement in dental ceramics, fabrication methods, and the challenges associated with clinical application. DATA, SOURCES AND STUDY SELECTION: Researches on chemical composition, biomechanical behaviors, optical properties, bonding strategies and fabrication methods were included. The search of articles was independently conducted by two authors in the PubMed, Scopus, Medline and Web of Science. CONCLUSIONS: Dental ceramics have shown significant advancements in terms of esthetics and function. However, improving fracture toughness without compromising optical properties remains a challenge. Repairing fractured zirconia or glass-matrix ceramic prostheses with the same material is difficult due to the sintering process. Developing innovative bonding techniques that provide strong and long-lasting bonding strength between ceramics and tooth structures poses a recurring obstacle. CLINICAL SIGNIFICANCE: Despite the emergence of dental ceramics and fabrication techniques, certain limitations such as susceptibility to brittleness and fracture still exist. Therefore, the current review provided valuable information around the advanced dental ceramics in tooth repair. The laboratory test data and the clinical outcome are also presented in details, aiming to guide clinicians in making informed decisions regarding ceramic restorations.

Evaluate the value of prolonging the duration of tiopronin for injection administration in preventing hepatotoxicity.

As part of supportive therapy, prophylaxis with tiopronin for injection (TI) against common hepatotoxicity complications has often been used. However, methods to prevent hepatotoxicity have not been established. Therefore, our study was aimed to find out the relationship between the periods of TI prophylaxis and post-treatment hepatotoxicity, and evaluated the value of prolonging the duration of TI administration in preventing hepatotoxicity. Hepatotoxicity was detected through liver transaminases, bilirubin, alkaline phosphatase, and clinical features of liver insufficiency. Multivariable logistic regressions were conducted to examine the association of the periods of TI prophylaxis and post-treatment hepatotoxicity. Between January 2022 and March 2023, a total of 452 patients with gynecological cancer were enrolled in the study, of which 93 (20.58%) participants were post-treatment hepatotoxicity positive. TI with different prevention days were no significant difference among participants with or without post-treatment hepatotoxicity in crude model (P > 0.05). The P-value, the odds ratios (OR) and 95% confidence intervals (CI) of participants with TI prophylaxis for 1 day for post-treatment hepatotoxicity were 0.040, 3.534 (1.061-11.765) in fully adjusted model. Past history of hepatotoxicity is a confounding variable, and there was no significant difference for post-treatment hepatotoxicity when stratified by past history of hepatotoxicity (P > 0.05). The study indicate that the periods of TI prophylaxis is not associated with post-treatment hepatotoxicity, suggesting that prolonged the periods of TI prophylaxis might be an invalid method for the prevention of post-treatment hepatotoxicity.

Trace Iron-Doped Nickel-Cobalt selenide with rich heterointerfaces for efficient overall water splitting at high current densities.

Developing bifunctional electrocatalysts based on non-precious metals for overall water splitting, while maintaining high catalytic activity and stability under high current densities, remains challenging. Herein, we successfully constructred trace iron-doped nickel-cobalt selenide with abundant CoSe2 (210)-Ni3Se4 (202) heterointerfaces via a simple one-step selenization reaction. The synthesized Fe-NiCoSex/NCFF (NCFF stands for nickel-cobalt-iron foam) exhibits outstanding hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) activity with low overpotentials of 328 mV for HER and 345 mV for OER at a high current density of 1000 mA cm-2, while maintaining stability for over 20 h. Additionally, the Fe-NiCoSex/NCFF exhibits the lowest Tafel slope values for both HER (33.7 mV dec-1) and OER (55.92 mV dec-1), indicating the fastest kinetics on its surface. The Fe-NiCoSex/NCFF features uniformly distributed micrometer-sized selenide particles with dense nanowires on their surface, providing a large reactive surface area and abundant active sites. Moreover, X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) analyses reveal that the catalyst is composed of nickel, cobalt, and iron, forming micrometer-sized particles with both crystalline and amorphous phases, thereby enhancing HER and OER performance under high current density. Density functional theory (DFT) calculations demonstrate that the heterostructure CoSe2 (210)-Ni3Se4 (202), with high electron density and suitable adsorption capacity for reaction intermediates, and low energy barriers for HER (-0.384 eV) and OER (ΔG1st: 0.243 eV, ΔG2nd: 0.376 eV), serves as an active center for both HER and OER.

Janus Membrane with Intrafibrillarly Strontium-Apatite-Mineralized Collagen for Guided Bone Regeneration.

Commercial collagen membranes face difficulty in guided bone regeneration (GBR) due to the absence of hierarchical structural design, effective interface management, and diverse bioactivity. Herein, a Janus membrane called SrJM is developed that consists of a porous collagen face to enhance osteogenic function and a dense face to maintain barrier function. Specifically, biomimetic intrafibrillar mineralization of collagen with strontium apatite is realized by liquid precursors of amorphous strontium phosphate. Polycaprolactone methacryloyl is further integrated on one side of the collagen as a dense face, which endows SrJM with mechanical support and a prolonged lifespan. In vitro experiments demonstrate that the dense face of SrJM acts as a strong barrier against fibroblasts, while the porous face significantly promotes cell adhesion and osteogenic differentiation through activation of calcium-sensitive receptor/integrin/Wnt signaling pathways. Meanwhile, SrJM effectively enhances osteogenesis and angiogenesis by recruiting stem cells and modulating osteoimmune response, thus creating an ideal microenvironment for bone regeneration. In vivo studies verify that the bone defect region guided by SrJM is completely repaired by newly formed vascularized bone. Overall, the outstanding performance of SrJM supports its ongoing development as a multifunctional GBR membrane, and this study provides a versatile strategy of fabricating collagen-based biomaterials for hard tissue regeneration.

Effect of pretreatment with calcium-containing desensitizer on the dentine bonding of mild self-etch adhesives.

Desensitizing agents are frequently applied to sensitive teeth and may affect subsequent resin bonding. The current study aimed to evaluate the bonding performance of two self-etch adhesives containing functional monomers to dentine pretreated with three new calcium-containing desensitizers. No desensitizer was applied in the control group. Groups 1, 2, and 3 were treated with an arginine-calcium carbonate-containing polishing paste, a casein phosphopeptide-amorphous calcium phosphate (CPP-ACP)-containing paste, and an experimental hydroxyapatite paste, respectively. G-Bond and Clearfil S(3) Bond were used for bonding after desensitizer treatments. The microtensile bond strength (µTBS) was tested (n = 20 beams per group) and failure mode distribution was analyzed. Scanning electron microscopy was used to observe the occlusion of dentinal tubules. The mean (±SD) µTBS values, expressed in MPa, of groups 1, 2, and 3 and the control group were, respectively, 30.81 (7.79), 44.41 (8.02), 31.49 (6.13), and 41.40 (8.67) for G-Bond and 39.63 (9.59), 32.55 (7.86), 37.50 (8.60), 27.90 (6.52) for S3 Bond. Most failures were recorded as adhesive failure (69.375%), instead of cohesive failure or mixed failure. The dentinal tubules were seldom plugged in group 2, but were mostly occluded in groups 1 and 3. Two-way anova indicated that desensitizer application in association with a compatible adhesive system should be used when endeavoring to control hypersensitivity without adverse interference in bonding.

Effect of a functional desensitizing paste containing 8% arginine and calcium carbonate on the microtensile bond strength of etch-and-rinse adhesives to human dentin.

PURPOSES: To evaluate (1) the effect of a desensitizing paste containing 8% arginine and calcium carbonate on the microtensile bond strength between dentin and etch-and-rinse adhesive systems; and (2) to examine the dentin tubules occlusion quantitatively. METHODS: 48 freshly extracted intact human mandibular third molars were divided randomly into three groups. The mid-coronal dentin of each tooth was exposed and treated. Group A: no treatment; Group B: specimens were polished with a desensitizing paste containing 8% arginine and calcium carbonate using a rotary cup operating at a low speed for 3 seconds, followed by an additional duration of 3 seconds (total operation time of 6 seconds), according to the manufacturer's instructions; Group C: specimens were handled in the same way with the exception of an increased operation time of 9 seconds, twice (total operation time of 18 seconds). Each group was randomly divided into two subgroups in order to evaluate the effectiveness of two different adhesive agents. A two-step etch-and-rinse adhesive agent (Adper SingleBond 2) and a three-step etch-and-rinse adhesive agent (Adper ScotchBond Multi-purpose) were applied to dentin surfaces. Then, microtensile bond strengths of the six subgroups were tested. Dentin surfaces were analyzed using field-emission scanning electron microscopy (FESEM) and laser scanning confocal microscopy (LSCM). RESULTS: There was no significant difference in microtensile bond strength between the control group and the experimental groups treated with the 8% arginine and calcium carbonate desensitizing paste during the application of etch-and-rinse adhesives. Both FESEM and LSCM showed that the desensitizing paste occluded dentin tubules effectively.

Programmed release of vascular endothelial growth factor and exosome from injectable chitosan nanofibrous microsphere-based PLGA-PEG-PLGA hydrogel for enhanced bone regeneration.

The healing of large bone defects remains a significant challenge in clinical practice. Accelerating both angiogenesis and osteogenesis can promote effective bone healing. In the natural healing process, angiogenesis precedes osteogenesis, providing a blood supply that supports the subsequent progression of osteogenesis. Developing a biomimetic scaffold that mimics the in vivo environment and promotes the proper sequence of vascularization followed by ossification is crucial for successful bone regeneration. In this study, a novel injectable dual-drug programmed releasing chitosan nanofibrous microsphere-based poly(D, l-lactide-co-glycolide)-b-poly(ethylene glycol)-b-poly(D,l-lactide-co-glycolide) (PLGA-PEG-PLGA) hydrogel is fabricated by incorporating vascular endothelial growth factor (VEGF) and microspheres loaded with dental pulp stem cells-derived exosomes (DPSCs-Exo). Rapid release of VEGF promotes the swift initiation of angiogenesis, while DPSCs-Exo release ensures persistent osteogenesis. Our results demonstrate that chitosan microsphere-based PLGA-PEG-PLGA hydrogel significantly promotes angiogenesis in human umbilical vascular endothelial cells and enhances the osteogenic differentiation of pre-osteoblasts. Furthermore, in vivo transplantation of this injectable chitosan microsphere-based PLGA-PEG-PLGA hydrogel into calvarial bone defects markedly promotes bone formation. Overall, our study provides a promising approach for improving bone regeneration by temporally replicating the behavior of angiogenesis and osteogenesis.

Extrafibrillarly Demineralized Dentin Matrix for Bone Regeneration.

Dentin is a natural extracellular matrix, but its availability in bone grafting and tissue engineering applications is underestimated due to a lack of proper treatment. In this study, the concept of extrafibrillar demineralization is introduced into the construction of dentin-derived biomaterials for bone regeneration for the first time. Calcium chelating agents with large molecular weights are used to selectively remove the extrafibrillar apatite minerals without disturbing the intrafibrillar minerals within dentin collagen, resulting in the formation of an extrafibrillarly demineralized dentin matrix (EDM). EDM with distinctive nanotopography and bone-like mechanical properties is found to significantly promote cell adhesion, migration, and osteogenic differentiation in vitro while enhancing in vivo bone healing of rat calvarial defects. The outstanding osteogenic performance of EDM is further confirmed to be related to the activation of the focal adhesion-cytoskeleton-nucleus mechanotransduction axis. Overall, this study shows that extrafibrillar demineralization of dentin has great potential to produce hierarchical collagen-based scaffolds for bone regeneration, and this facile top-down fabrication method brings about new ideas for the biomedical application of naturally derived bioactive materials.