Six-year clinical evaluation of iRoot BP Plus as apical barrier in permanent teeth of periapical periodontitis.

The apical barrier technique in permanent teeth with extensive destruction of the periapical tissue and a long infection time is much more difficult to succeed, which is a clinical challenge. This study aimed to evaluate the long-term effects of iRoot BP Plus as an apical material in adult teeth. Fifty incisors and premolars were chosen for this study. All teeth were performed apical barrier with the same operator. After treatment, the teeth were clinically and radiographically evaluated at 1, 2 and 6 years. At the 1-year follow-up, 35 teeth had healed, and three patients developed an apical abscess due to root fracture at the 2-year follow-up. Six years postoperatively, one tooth showed root resorption, which was considered a failure. The long clinical evaluation confirmed that iRoot BP Plus is a suitable material for the apical barrier of mature teeth with open apices and periapical lesions.

Selective purification and rapid quantitative detection of spores using a "stepped" magnetic flow device.

A study on the inactivation and germination mechanism of spores is very important in the application of spores, as such high-purity spores are the basis of related research. However, spores and vegetative cells of bacteria often coexist, and it is difficult to separate them. In this study, a magnetic flow device for the purification of spores in the culture medium system was developed based on a "stepped" structure with a magnetic force that could absorb vegetative cells with magnetic nanoparticles. The operation process was as follows: first, vancomycin functionalized nanoparticles were used to prepare Van-Fe3O4 NPs, which were then combined with vegetative cells to form a magnetic conjugate. Subsequently, the magnetic conjugate (vegetative cells) flowed through the "stepped" magnetic flow device and was adsorbed. Meanwhile, the spores moved through the channel and were collected. The achieved purity of the collected spores was more than 95%. Further, the number of the obtained spores was quickly quantified using Raman spectroscopy. The entire purification and quantitative process can be completed within 30 min and the limit of detection was 5 CFU mL-1. This study showed outstanding spore purification ability and provided a new method for purification and rapid quantitative detection of spores.

New-designed 3D printed surgical guide promotes the accuracy of endodontic microsurgery: a study of 14 upper anterior teeth.

We aimed to design a novel three-dimensional (3D) printed surgical guide and evaluate its accuracy in assisting endodontic microsurgeries. A new 3D printed surgical guide was designed by computer-aided design and computer-aided manufacturing (CAD/CAM) technology and applied to 7 patients who underwent endodontic microsurgeries of upper anterior teeth from 2020.01 to 2020.12 as the experimental group. 7 patients who suffered from endodontic microsurgeries operated by the same surgeon without using the surgical guide from 2019.01 to 2019.12 were selected as the control group. Cone beam computed tomography (CBCT) was performed more than 12 months after operation, and the accuracy of apical resection was compared between the two groups. The accuracy of the microsurgery focused on the length and angle of the root apical resection. In the study, CBCT data and oral digital scanning data were used to reconstruct 3D models of periapical lesions with soft and hard tissue information, based on which we designed the new 3D printed surgical guides. The guides were successfully applied to the apectomy in endodontic microsurgeries. The deviation of the apical resection length of the experimental group (0.467 ± 0.146 mm) was better than that of the control group (1.743 ± 0.122 mm) (P < 0.0001), and the deviation of the apical resection angle of the experimental group (9.711 ± 3.593°) was significantly less than that of the control group (22.400 ± 3.362°) (P < 0.0001). The 3D-printed surgical guide could effectively guide endodontic microsurgery and improve its accuracy by fixing both the position and the angle of apectomy. The new type of surgical guide could accurately localize the root apex and guide the apical resection.

Polarization-Independent Optoelectronic Modulator Based on Graphene Ridge Structure.

In this paper, we propose a polarization-independent optoelectronic modulator based on the electrical absorption effect of graphene. Firstly, we use the simulation software COMSOL Multiphysics to design the structure, and find via changing the applied voltage on both ends of the graphene that the equivalent refractive index of graphene can be changed, thus changing the light absorption capacity of the modulator. The waveguides in the transverse magnetic (TM) and transverse electric (TE) modes have almost the same extinction coefficient by making a double-layer graphene ridge structure in the center of the silicon-based waveguide, which can achieve approaching modulation depth in the TM and TE modes. At 1550 nm wavelength, the two-dimensional cross-section of the structure is analyzed by the FEM method using COMSOL Multiphysics to obtain the effective refractive index of the structure. The simulation results show that when the distance between the double-layer graphene isolation layer is d = 20 nm, the TE and TM modes can achieve extinction ratios up to 110 dB over the wide communication band by selecting appropriate "ON" and "OFF" switching points. The bandwidth is 173.78 GHz and the insertion loss is only 0.0338 dB.

Effect of magnetic powder on denitrification using the sludge alkaline fermentation liquid as a carbon source.

This work evaluates the impact of the different concentrations of Fe3O4 on nitrate removal and organic matters utilization in the sequencing batch reactors (SBRs) using the sludge alkaline digestion supernatant as external sludge carbon source. Results indicated that the optimal concentration of Fe3O4 was 1 g/L for enhancing denitrification with NO3--N removal efficiency of 93.13% (up to a 11.93% increase) and without NO2--N accumulation after 18 days. The changes of soluble chemical oxygen demand (SCOD), protein, and carbohydrate during denitrification process were analyzed to gauge the utilization of sludge fermentation products by denitrifiers. The SCOD was consumed for organisms involved in NO3--N removal and the Fe3O4 could promote the utilization of carbohydrate better than protein by denitrifiers during denitrification process. Denitrification rate (VDN) and the nitrate-to-nitrite transformation ratio (NTR), as the kinetics parameters, were also investigated in different concentrations of Fe3O4.

[A Surface Plasmon Micro-Ring Sensor Suitable for Humidity Sensing].

Temperature is a very important parameter in scientific research, production and life. Almost all the properties of materials are related to temperature. The precise measurement of the temperature is a very important task, so the temperature sensor is widely used as a core part in the temperature measuring instrument. A novel surface plasmon micro-ring sensor suitable for humidity sensing is presented in this paper. The sensor uses a multi-layered surface plasmon waveguide structure and choosing Polyimide (Polyimide, PI) as the moisture material. We get the transfer function of surface plasmon micro-ring sensor by using transfer matrix method. Refractive indexes of Polyimide and the multilayer waveguide structure change as environment relative humidity changes, thus leading to an obvious peak drift of output spectrum. The paper mainly discusses the influence of the changes of the refractive index of humidity-sensing parts on the output spectrum, and the transmission characteristics of multilayer waveguide structure. Through the finite element method and the theoretical simulation of Matlab, We can draw: When the length between the two coupling points of the U-shaped waveguide is an integer multiple of circumference of the micro-ring, an obvious drift in the horizontal direction appears, the free spectral range (FSR) doubled and the sensitivity is 0.0005 µm/%RH; When the external environment relative humidity RH changes from 10% to 100% RH, scatter is change between including (including 0.005 m to 0.005 m, compared to other humidity sensor, the Sensitivity of sensor improves 10~50 times and the transmission is very stable. Results show that the design of surface plasma micro ring sensors has better sensitivity, stable performance and can be used in the humidity measurement, achieving a high sensitivity in the sense of humidity when the wide range of filter frequency selection is taken into account, and providing a theoretical basis for the preparation of micro-optics.

Dentin sialophosphoprotein: a regulatory protein for dental pulp stem cell identity and fate.

The dentin sialophosphoprotein (dspp) transcript is expressed during tooth development as a DSPP precursor protein, which then undergoes cleavage to form mature dentin sialoprotein (DSP) and phosphophoryn (PP) proteins. Previous studies using DSPP-knockout (KO) mice have reported that these animals have hypomineralized teeth, thin dentin, and a large dental pulp chamber, similar to those from patients with dentinogenesis imperfecta III. However, there is no information about factors that regulate dental pulp stem cell lineage fate, a critical early event in the odontoblast-dentin mineralization scheme. To reveal the role of DSPP in odontoblast lineage differentiation during tooth development, we systematically examined teeth from wild-type (wt) and DSPP-KO C57BL/6 mice between the ages of postnatal day 1 and 3 months. We found developmental abnormalities not previously reported, such as circular dentin formation within dental pulp cells and altered odontoblast differentiation in DSPP-KO mice, even as early as 1 day after birth. Surprisingly, we also identified chondrocyte-like cells in the dental pulp from KO-mice teeth. Thus, these studies that compare wt and DSPP-KO mice suggest that the expression of DSPP precursor protein is required for normal odontoblast lineage differentiation and that the absence of DSPP allows dental pulp cells to differentiate into chondrocyte-like cells, which could negatively impact pulpal wound healing and tissue regeneration.

[Study of spectrum characteristic of humidity sensor based on series coupled two micro-ring resonators].

A novel humidity sensor of polyimide (PI) based on the series coupled two-micro-ring resonators is proposed in the present paper. The transfer function of the micro ring resonator was calculated by using the transfer matrix method and the coupled mode theory. The authors compared the output spectrum characteristics of the traditional single micro-ring and series coupled two-micro-ring with different radii. The refractive index of the PI waveguide changes with different environmental humidity and this will lead to the drift of the output spectrum of the micro-ring resonator. By detecting the drift of the output spectrum we can measure the humidity, and the sensitivity and the sensing-range of the sensor are acquired accordingly. We also analyzed the output spectrum characteristics of resonators at different humidity sensing part. The theoretical results show the good performance of humidity sensor which could be used as the optimum sensing unit when the whole structure of the series coupled two-micro-ring resonators serves as the sensing part. The sensing-range and sensitivity of the system are improved by series micro-ring resonators of different radii compared to the conventional sensor with single micro-ring resonator. The free spectral range (FSR) of resonator reaches to 0.15 µm, the sensing-range is 10% RH-80% RH, and the sensitivity is 0.001 7 µm (% RH)(-1). Series coupled two-micro-ring with different radii gives theoretical instruction for producing integrated humidity sensor with low-cost, simple structure and high sensitivity.

[Differential proteomics analysis of dental pulp cell induced by recombinant human interleukin-1beta].

OBJECTIVE: To compare the proteomics change of human dental pulp cells induced by recombinant human interleukin-1beta (rhIL-1beta). METHODS: The dental pulp cell entire protein was separated by a two-dimensional electrophoresis (2-DE) technique. The rhIL-1beta induction and the normal dental pulp cell protein 2-DE atlas were established. Difference expression protein was confirmed by ImageMaster 2D Elite 5.0 software analysis. To identify differentially expressed proteins spot by matrix-assisted laser desorption/ionization time of flight mass spectrometry, and get peptide mass fingerprinting. RESULTS: Comparing the two groups of protein 2-DE atlas, 39 protein spots were obviously different. Including 15 points in the induction of protein expression were higher, 13 new protein spots, 7 protein points expressions were lower, there were only four points in the control group. After mass spectra identification, 10 protein spots were confirmed at last. CONCLUSION: Pulp cells to rhIL-1beta responsiveness is a very complex process, which involve a variety of protein molecules, rhIL-1beta related 10 protein spots have been identified in the dental pulp cell for the first time. To explore pulpitis's early response mechanism provides a new clue and ideas.