3D-printed coloured tooth model for inlay preparation in pre-clinical dental education.

INTRODUCTION: Accurate inlay preparation is extremely important in pre-clinical training. However, there is a lack of tools to guide students to efficiently practise inlay preparation. Therefore, a 3D-printed coloured tooth model for inlay preparation was designed to guide beginners to practise inlay preparation by themselves according to different colour prompts. This study aimed to evaluate the benefits of using a 3D-printed coloured tooth model in the pre-clinical training on inlay preparation. MATERIALS AND METHODS: Twenty-eight students in their fourth-year undergraduate dental program participated in this study. The participants were randomly assigned to two groups for the inlay preparation. Group 1 prepared a plain tooth model for the first and fourth attempts and a 3D-printed coloured tooth model for the second and third attempts (n = 14). Group 2 prepared four plain tooth models (n = 14). The first and fourth tooth models prepared by both groups were scored using an evaluation system (Fair Grade 2000, NISSIN). Next, questionnaires answered by students were used to evaluate the benefits of using a 3D-printed coloured tooth model and self-evaluate hands-on ability using a grading system (1 = strongly agree, 2 = agree, 3 = neutral, 4 = disagree, and 5 = strongly disagree). The scores were evaluated statistically using the Mann-Whitney U test, and the given grades are displayed as percentages and mean values. RESULTS: There was an overall increase in the clinical confidence of all students after repeated attempts to prepare an inlay; however, students from group 1, who had used the 3D-printed coloured tooth model, had more positive experiences and comments. The 3D-printed coloured tooth model for inlay preparation has been widely praised by participants. Comparing the average score of the first and fourth preparations, the average score of group 1 increased by 12% (Ø 54.46 ± 8.33, Ø 61.11 ± 7.13, p = .090), while that of group 2 increased by 0.72% (Ø 56.39 ± 9.59, Ø 56.80 ± 8.46, p = .925). CONCLUSION: Students favoured the use of the 3D-printed coloured tooth model, and this improved the average score for inlay preparation. The 3D-printed coloured tooth model for inlay preparation is expected to play an important role in dental education in the future.

Fully digital workflow for replicating treatment dentures: A technique for jaw relation transfer and dynamic occlusal adjustment.

This technique report presents a novel method of digitally replicating a treatment denture and converting it into a definitive denture. The procedure accurately duplicates the appearance of the mucosal surface and border of the treatment dentures, mounts the jaw relation on a virtual articulator to arrange artificial teeth, and optimizes the occlusion based on recorded mandibular motion tracks. This technique uses personalized jaw relation transfer and dynamic occlusal adjustment to establish balanced occlusion, which accomplishes the digital duplication of the treatment denture with high accuracy and minimal effort.

A digital workflow for complete arch rehabilitation with zirconia crowns on restored posterior teeth and a polyetheretherketone framework denture.

A clinical and laboratory workflow for the digital design and fabrication of zirconia crowns and polyetheretherketone removable partial dentures for complete arch rehabilitation is described. The definitive crowns and polyetheretherketone framework can be delivered simultaneously because of the digital design and milling fabrication with retentive areas, guide planes, and rest seats in high-translucency zirconia crowns. The workflow helps simplify clinical and laboratory procedures and reduces patient visits and chairside time.

An Indirect Digital Technique to Transfer 3D Printed Casts to a Mechanical Articulator With Individual Sagittal Condylar Inclination Settings Using CBCT and Intraoral Scans.

With the widespread application of digital impression techniques in prosthetic dentistry, accurate intraoral scan mounting, and virtual articulator parameters setting as per patients' anatomic structures are essential for treatment planning and restoration fabrication, especially for complex rehabilitation cases; meanwhile, marginal fit checking, occlusal adjustment, and porcelain layering of restorations are also crucial procedures in all cases in which the analog procedure to mount maxillary arches on a mechanical articulator is still required. This technique article presents an indirect digital approach that can first achieve virtual intraoral scan mounting and sagittal condylar inclination value setting of an Artex virtual articulator based on bony structures provided by a single cone beam computed tomography scan. It then facilitates the transfer of virtually mounted intraoral scans from the virtual articulator to the matched Artex mechanical articulator by relating a digitally scanned mounting plate of the Artex mechanical articulator to the virtual articulator, printing the intraoral scan and mounting plate scan assembly, and then mounting the printed casts on the mechanical articulator based on the printed mounting plate. This technique eliminates the conventional facebow transfer and protrusive bite registration procedures and offers a straightforward approach for the seamless integration of virtual environments and analog workflows into clinical practice. It aids in the design of restorations that are harmonious with the mandibular movements and reduces chairside adjustment time.

Adaptive incremental method for strain estimation in phase-sensitive optical coherence elastography.

We proposed an adaptive incremental method for the cumulative strain estimation in phase-sensitive optical coherence elastography. The method firstly counts the amount of phase noise points by mapping a binary noise map. After the noise threshold value is preset, the interframe interval is adaptively adjusted in terms of the phase noise ratio. Finally, the efficient estimation of cumulative strain is implemented by reducing the cumulative number. Since the level of phase noise is related to the different strain rates in accordance with the speckle decorrelation, the proposed method can estimate the large strains with high computation efficiency as well as signal-to-noise ratio (SNR) enhancement in nonlinear change of sample deformations. Real experiments of visualizing polymerization shrinkage with nonlinear change of deformations were performed to prove the superiority of adaptive incremental method in estimating the large strains. The proposed method expands the practicability of the incremental method in more complex scenes.

Direct composite resin restoration of a class IV fracture by using 3D printing technology: A clinical report.

Mimicking the appearance of the adjacent natural tooth is challenging when restoring a fractured anterior tooth. This clinical report describes a modified index technique for restoring a class IV defect. A replica of the restored tooth was fabricated with computer-aided design and 3D printing technology, which precisely mimicked the contralateral incisor. Labial and lingual silicone indices were developed on the replica to transfer the designed contour to the tooth to achieve a highly esthetic and precise restoration.

A digital workflow with computer-assisted implant planning for fabricating an impression splinting framework and custom tray for multiple implants.

A fully digital workflow for designing and manufacturing a splinted framework and a custom tray for the impression of multiple implants placed with guided surgery is described. This digital workflow protocol does not require extra visits after surgery to prepare for the definitive impression because of the use of preoperative digital implant planning data. As a result, it helps reduce laboratory procedures, chairside time, and treatment cost.

Registering Maxillomandibular Relation to Create a Virtual Patient Integrated with a Virtual Articulator for Complex Implant Rehabilitation: A Clinical Report.

The virtual patient, a unique computer simulation of the patient's face, teeth, oral mucosa, and bone, provides an extraordinary mechanism for digital dental implant surgery planning and prosthetic design. However, the seamless registration of digital scans with functional information in the context of a virtual articulator remains a challenge. This report describes the treatment of a 47-year-old male with full-mouth guided immediate implant placement and immediate loading of CAD/CAM interim prostheses. Utilizing a novel digital workflow, a multifactorial registration of the vertical dimension of occlusion, centric occlusion, and facebow record were completed digitally and paired within a digital articulator. Utilizing this innovative approach, a complex treatment plan and procedure was executed smoothly with a successful prosthetic outcome demonstrating good fit, occlusion, esthetics, and patient reported satisfaction.

Determining electrospun morphology from the properties of protein-polymer solutions.

Integrating natural macromolecules, e.g. proteins, is a progressive trend in the fabrication of biocompatible sub-micrometer fibers with tunable diameters using the electrospinning technique. The correlation between solution properties and electrospun morphology is critical; it is quite clear for synthetic linear polymer solutions but remains uncertain for solutions with protein. Here, we report the determination of electrospun morphology in protein-polymer solutions of poly(ethylene oxide) (PEO) and zein, a storage protein from corn. The viscosity of the zein/PEO mixed solutions can be well described using the Lederer-Roegiers equation and decreases with the increase of the fraction of zein. The surface tension sharply decreases above a critical concentration at the saturation of the interfacial monolayer. Correspondingly, the different electrospun morphologies-from bead, coexisting bead and fiber, to fiber and ribbon-were mapped onto a ternary phase diagram and a viscosity contour plot. Such coupling provides a clear way to determine the electrospun morphology from solution properties. The occurrence of electrospun fibers partially follows two empirical rules, while the critical point revealed from surface tension has the best approximation. The diameters of electrospun fibers were found to have a scaling relationship against concentration, zero-shear viscosity and surface tension of solutions. These scaling exponents were compared with those from typical polymer solutions. The analysis suggests that aqueous ethanol gives different solvent qualities to zein and PEO solutions, resulting in the irregular shape in the phase diagram that correlates solution properties and electrospun morphologies.

Effect Soft Measurement Model of Steel Slag Powder Repair Heavy Metal Contaminated Soil with Fourier Transform Infrared Spectrum.

Using converter slag as curing stabilizing agents, applying Toxicity Characteristic Leaching Procedure (TCLP) and Fourier transform infrared spectroscopy method of tracking and detection of heavy metals in soil remediation effect of slag powder, and the micro-structure of mixtures (slag powder and heavy metal contaminated soils). It can establish soft sensor mode which is based on Gaussian process regression slag powder on heavy metal contaminated soil remediation effect. by using Gaussian process regression. The results show that the steel slag powder on heavy metals contaminated soil has good repairing effect, 180 d within its restorative effects are maintained over 90%; the repair process is divided into early, middle and late stages, in which the early (1~3 d) repair mode is given priority to with ion exchange high alkaline environment, medium-term (7~42 d) ion exchange and gel setting weaken the enhanced role of the late (56~180 d) form a large number CSH gel, the gel solidification further strengthened; based on Gaussian process regression Steel slag powder on heavy metal contaminated soil remediation effect soft measurement model of the real and predicted values agree well with the data, the absolute error is -1.35 ~-0.48, relative error of -1.448%～-0.497%.

[Recognition study of double strand DNA with hairpin oligopolyamide].

Selective recognition of double strands DNA(ds DNA) has been a research hot spot in molecular biology and biomedicine for a couple decades. Based on the selective interaction between natural nucleic acid/synthetic molecular ligands and ds DNA, gene diagnosis, gene therapy and gene editing would be realized. Hairpin oligopolyamide is a molecular ligand with excellent cellular permeability and nucleases-resistance which can target ds DNA sequence with high affinity and specificity at minor groove. This paper reviews the binding properties and biomedical applications of hairpin oligopolyamide targeting ds DNA, which provide references for further design and application of hairpin oligopolyamide.

[Preparation of curcumin-loaded long-circulating liposomes and its pharmacokinetics in rats].

Curcumin has a wide spectrum of pharmaceutical properties such as antitumor, antioxidant, antiamyloid, and anti-inflammatory activity. However, poor aqueous solubility and low bioavailability of curcumin are major challenge in its development as a useful drug. To overcome many of these problems, curcumin-loaded long-circulating liposomes (Cur-LCL) were prepared by the ethanol injection method. Morphology of Cur-LCL was observed by transmission electron microscope, mean particle size and Zeta potential were detected by laser particle size analyzer, entrapment efficiency and drug loading were evaluated by ultracentrifugation. The drug release behavior in vitro and pharmacokinetic behavior in rats of Cur-LCL were investigated with curcumin (Cur) and curcumin liposomes (Cur-Lips) as control. The results showed that the mean diameter of Cur-LCL was 110 nm, the Zeta potential was -5.8 mV. The entrapment efficiency and drug loading of Cur-LCL was 80.25%, 2.06%, respectively. The release behavior in vitro studied by dialysis in PBS buffer showed significant sustained release profile that 48.95% Cur were released from Cur-LCL in 7 h, 88.92% in 24 h. The pharmacokinetic parameters showed that compared with Cur and Cur-Lips, the t(1/2beta) of Cur-LCL was extended to 13 and 1.8-fold, respectively. Besides, the AUC values was significantly increased (P < 0.01), and the clearance was evidently decreased (P < 0.01). These results from in vitro and in vivo indicated that Cur-LCL were able to realize controlled drug release and increase circulation time.

Flexible Arc-Shaped Micro-Fiber Bragg Grating Array Three-Dimensional Tactile Sensor for Fingertip Signals Detection and Human Pulse Monitoring.

A flexible arc-shaped micro-Fiber Bragg Grating (mFBG) array three-dimensional tactile sensor for fingertip signal detection and human pulse monitoring is presented. It is based on a three mFBGs array which is embedded in an arc-shaped poly (dimethylsiloxane) (PDMS) elastomer, which can effectively discriminate the normal force, left force, and right force by monitoring the reflected intensity variation of the three mFBGs. Different from the traditional FBG sensors, this sensor measures force by detecting changes in light intensity, effectively avoiding the wavelength cross-sensitivity impact of temperature variations on the sensor performance. This design strategy simplifies the sensor structure, reduces the system complexity and signal interrogation cost, and enhances reliability and practicality. Through systematic experiments, we successfully validated the sensor's superior performance, achieving a minimum detection force of 0.01 N and providing robust data support for practical applications. In addition, the sensor has been used to monitor human pulse accurately. The successful fabrication and experimental validation of this sensor lay a foundation for its widespread application in fields such as robot perception and human vital signal detection.

Extracellular Matrix-Mimetic Intrinsic Versatile Coating Derived from Marine Adhesive Protein Promotes Diabetic Wound Healing through Regulating the Microenvironment.

The management of diabetic wound healing remains a severe clinical challenge due to the complicated wound microenvironments, including abnormal immune regulation, excessive reactive oxygen species (ROS), and repeated bacterial infections. Herein, we report an extracellular matrix (ECM)-mimetic coating derived from scallop byssal protein (Sbp9Δ), which can be assembled in situ within 30 min under the trigger of Ca2+ driven by strong coordination interaction. The biocompatible Sbp9Δ coating and genetically programmable LL37-fused coating exhibit outstanding antioxidant, antibacterial, and immune regulatory properties in vitro. Proof-of-concept applications demonstrate that the coating can reliably promote wound healing in animal models, including diabetic mice and rabbits, ex vivo human skins, and Staphylococcus aureus-infected diabetic mice. In-depth mechanism investigation indicates that improved wound microenvironments accelerated wound repair, including alleviated bacterial infection, lessened inflammation, appearance of abundant M2-type macrophages, removal of ROS, promoted angiogenesis, and re-epithelialization. Collectively, our investigation provides an in situ, convenient, and effective approach for diabetic wound repair.

Simultaneous determination of furfural, acetic acid, and 5-hydroxymethylfurfural in corncob hydrolysates using liquid chromatography with ultraviolet detection.

A single-laboratory validation study was conducted using HPLC for detecting and quantifying acetic acid, furfural, and 5-hydroxymethylfurfural (HMF) in corncob hydrolysates. A pretreatment procedure using dilute sulfuric acid was optimized for corncob hydrolysis. The final hydrolysates were analyzed by HPLC using a C18 RP column with aqueous 0.01% (v/v) H2SO4-CH3OH (95 + 5) as the mobile phase at a flow rate of 1 mL/min. The wavelengths for detecting the three compounds were changed to their optimal UV detection wavelengths at the time of elution. The wavelength detection adjustments were as follow: 205 nm (0 to 4 min); 284 nm (4 to 7 min); and 276 nm (7 to 10 min). Separation was achieved with a chromatographic run time of 10 min. The calibration curves for the three compounds had correlation coefficients (r2) > or = 99.8%. The analytical range, as defined by the calibration curves, was 0.5-10 mg/L for acetic acid, 0.4-22 mg/L for furfural, and 0.1-18 mg/L for HMF. The LODs for acetic acid, furfural, and HMF were estimated to be 0.05, 0.03, and 0.02 mg/L, respectively; the LOQs were 0.196, 0.135, and 0.074 mg/L, respectively. The RSD values for the intraday precision study ranged from 0.31 to 2.22%, and from 0.57 to 2.43% for the interday study. The mean recovery rates in all compounds were between 100.08 and 101.49%.

Esthetic rehabilitation for a Kennedy Class IV patient using detachable 3D printing diagnostic denture and removable partial denture with polyetheretherketone framework.

For patients with high aesthetic expectation, using removable partial dentures (RPDs) to restore the missing teeth in the aesthetic area rapidly and obtain the patients' approval is challenging. This case described an alternative digital protocol to solve this situation. A detachable 3DP diagnostic denture was involved in the procedure, which not only allowed patient to evaluate the possible outcome of the RPD, but also can be duplicated to form a definitive RPD, by bonding a milled PEEK framework and a customized PMMA dentition containing posts, using a thermoplastic compression molding (CM)process.

Application of polymeric porcelain color-masking cast posts in the aesthetic repair of anterior teeth: a case report.

Many patients with large-area tooth defect need cast post-core crown restoration. However, the color defect of the cast post-core will affect the final restorative result, especially that of the anterior teeth. A new technology of color masking by applying CERAMAGE polymeric porcelain to the cast metal post-core surface improves the color of a full-ceramic restoration of anterior teeth and may provide a new alternative for the aesthetic repair of anterior teeth with a large area of defective tooth.

Manganese waste water treatment by fungi derived from manganese slag.

The aim of this study was to isolate a mould from the surface of manganese slag which had strong resistance and high adsorption of Mn(2 + ), and to determine the effects of initial Mn(2 + ) concentration, incubation temperature, rotation speed and inoculation amount on adsorption of Mn(2 + ) from manganese waste water solution. The result showed that a mould (A5) which was isolated from manganese slag had the adsorption rate of Mn(2 + ) to 97.5% at the initial pH value 6, inoculation amount 2%, rotation speed 150 r/min, a concentration of Mn(2 + ) 500 mg/L, and a temperature of 28 degrees C cultivated for 50 h. As there is no research on adsorption of Mn(2 + ) from manganese waste water by fungi before, this research showed a theoretical guidance on this field.

[Precise tooth preparation technique guided by 3D printing guide plate with quantitative hole].

The minimum amount of tooth preparation that can be fully controlled is crucial in achieving long-term, stable, and effective aesthetic restoration, which is also a major difficulty in aesthetic restoration. The tooth preparation can be imple-mented efficiently and accurately through digital technology based on the fixed-deep hole guiding technology. Prior the actual tooth preparation, the technology first designs the virtual contour, layering, and virtual occlusion of the prosthesis on the computer. Then, virtual tooth preparation is carried out by cutting back according to the virtual prosthesis. Next, the virtual drilling operation plan is designed according to the shape of the virtual tooth preparation and the contour of the abutment tooth. Finally, the tooth preparation guide plate is designed and printed in 3D. It realizes the whole process of quantitative and precise guidance of dental preparation, visualizes the restoration space, reduces the clinical operation time, and guarantees the quality of dental preparation. It also promotes the improvement of the teaching quality of digital practical exercises.

Reversible Self-Assembly of Nanoprobes in Live Cells for Dynamic Intracellular pH Imaging.

Self-assembly is a powerful tool to organize the elementary molecular units into functional nanostructures, which provide reversible stimulus-responsive systems for a variety of purposes. However, the ability to modulate the reversible self-assembly in live systems remains a great challenge owing to the chemical complexity of intracellular environments, which often damage synthetic assembled superstructures. Herein, we describe a robust reversible self-assembly system that is composed of a hydrophobic gold nanoparticle (AuNP) core and a shell of pH-responsive dye-incorporated block copolymers. The reversible assembly-disassembly processes were precisely controlled through mediating the molecular interactions between the copolymers and AuNPs. More importantly, the major endogenous biospecies such as proteins will not impair the reversible self-assembly, which was supported by free-energy calculations. The reversible pH-responsive nanostructures were employed as "smart" probes for visualizing the subtle dynamic pH changes among different intracellular compartments, facilitating the study of pH influence on biological processes.