Bone Regeneration in Implant Dentistry: Role of Mesenchymal Stem Cells

This chapter focuses on a review of the activity of non-embryonic mesenchymal stem cells used to regenerate jaw bones in dentistry. Recent research of non-embryonic stem cells provides new possibilities for noninvasively obtaining new autologous bone from stem cells provided by various tissues from the same patient. Disaggregation of biologic tissue harvested from the patients during surgery permits extraction of stem cells from a small sample of connective tissue obtained from the patient’s lingual mucosa or from the postextraction surgical site where the endosseous implant will be inserted

New collagen‐coated calcium phosphate synthetic bone filler (Synergoss®): A comparative surface analysis

n/

Essential nonlinearities in hearing

Our hearing organ, the cochlea, evidently poises itself at a Hopf bifurcation to maximize tuning and amplification. We show that in this condition several effects are expected to be generic: compression of the dynamic range, infinitely shrap tuning at zero input, and generation of combination tones. These effects are "essentially" nonlinear in that they become more marked the smaller the forcing: there is no audible sound soft enough not to evoke them. All the well-documented nonlinear aspects of hearing therefore appear to be consequences of the same underlying mechanism.Comment: 4 pages, 3 figure

Differences between panoramic and Cone Beam-CT in the surgical evaluation of lower third molars

The aim of this study was to evaluate the ability to identify the contiguity between the root of the mandibular third molar and the mandibular canal (MC) in panoramic radiographs compared with Cone Beam-CT. Panoramic radiographs of 326 third molars and CBCT radiographs of 86 cases indicated for surgery and considered at risk were evaluated. The following signs were assessed in panoramic radiographs as risk factors: radiolucent band, loss of MC border, change in MC direction, MC narrowing, root narrowing, root deviation, bifid apex, superimposition, and contact between the root third molar and the MC. Radiographic signs associated with absence of MC cortical bone are: radiolucent band, loss of MC border, change in MC direction, and superimposition. The number of risk factors was significantly increased with an increasing depth of inclusion. CBCT revealed a significant association between the absence of MC cortical bone and a lingual or interradicular position of the MC. In cases in which panoramic radiographs do not exclude contiguity between the MC and tooth, careful assessment the signs and risks on CBCT radiographs is indicated for proper identification of the relationships between anatomic structures

Micro-Raman Spectroscopy of Dental Implants Subjected to Different Surface Treatments

The aim of the study was to qualitatively investigate the structure of the surface layer of TiO2 on dental implants made of Ti-6Al-4V subjected to different manufacturing treatments. M (machined), B (Al2O3-blasted), E (HNO3HF-etched), B + E and A (B + E + anodized) implants and a further group receiving the same treatments as the first group with the addition of a final decontamination with cold plasma were included in the study. Examination was performed using micro-Raman spectroscopy. The surface treatments evaluated did not achieve the formation of crystalline TiO2. The increase in the complexity of surface treatment produced a proportional increase in the thickness of amorphous TiO2 oxide. In the B + E group, the plasma treatment enhanced the amorphous oxide thickness of TiO2. The other surfaces treated by plasma decontamination did not show a difference to the respective untreated ones. The investigated surface treatments did not change the crystalline cage of TiO2 in Ti-6Al-4V implants but affected the thickness of the oxide layer. The biological response could be influenced by different oxide thicknesses. Additional information on superficial TiO2 structural organization can be obtained by micro-Raman evaluation of dental implants. Dental implants with B + E + plasma and A superficial treatments allowed the maximum formation of the amorphous oxide thickness

The Association Between Body Mass Index and Anxious Arousal, Depressive, and Insomnia Symptoms Among World Trade Center Responders

Elevations in body mass index (BMI) among World Trade Center (WTC) responders may be associated with poor mental health outcomes. The current study examined the association of BMI with anxious arousal, depressive, and insomnia symptoms among this group. Participants were 412 WTC responders (89.4% male, Mage = 55.3 years, SD = 8.66) who completed health monitoring assessments (self-report and objective) as part of the Long Island site of the WTC Health Program (LI-WTC-HP). Results suggested BMI was statistically significant only in relation to anxious arousal (sr2 = .02, p = .008), after accounting for age and sex. The current study suggests that weight management programs may aid in promoting additional benefits for WTC responders by reducing anxious arousal symptoms as a function of reduced BMI

Silver-doped Calcium Phosphate bone cements with antibacterial properties

Calcium phosphate bone cements (CPCs) with antibacterial properties are demanded for clinical applications. In this study, we demonstrated the use of a relatively simple processing route based on preparation of silver-doped CPCs (CPCs-Ag) through the preparation of solid dispersed active powder phase. Real-time monitoring of structural transformations and kinetics of several CPCs-Ag formulations (Ag = 0 wt %, 0.6 wt % and 1.0 wt %) was performed by the Energy Dispersive X-ray Diffraction technique. The partial conversion of β-tricalcium phosphate (TCP) phase into the dicalcium phosphate dihydrate (DCPD) took place in all the investigated cement systems. In the pristine cement powders, Ag in its metallic form was found, whereas for CPC-Ag 0.6 wt % and CPC-Ag 1.0 wt % cements, CaAg(PO₃)₃ was detected and Ag (met.) was no longer present. The CPC-Ag 0 wt % cement exhibited a compressive strength of 6.5 ± 1.0 MPa, whereas for the doped cements (CPC-Ag 0.6 wt % and CPC-Ag 1.0 wt %) the reduced values of the compressive strength 4.0 ± 1.0 and 1.5 ± 1.0 MPa, respectively, were detected. Silver-ion release from CPC-Ag 0.6 wt % and CPC-Ag 1.0 wt % cements, measured by the Atomic Emission Spectroscopy, corresponds to the average values of 25 µg/L and 43 µg/L, respectively, rising a plateau after 15 days. The results of the antibacterial test proved the inhibitory effect towards pathogenic Escherichia coli for both CPC-Ag 0.6 wt % and CPC-Ag 1.0 wt % cements, better performances being observed for the cement with a higher Ag-content

ATF4 couples MYC-dependent translational activity to bioenergetic demands during tumour progression.

The c-Myc oncogene drives malignant progression and induces robust anabolic and proliferative programmes leading to intrinsic stress. The mechanisms enabling adaptation to MYC-induced stress are not fully understood. Here we reveal an essential role for activating transcription factor 4 (ATF4) in survival following MYC activation. MYC upregulates ATF4 by activating general control nonderepressible 2 (GCN2) kinase through uncharged transfer RNAs. Subsequently, ATF4 co-occupies promoter regions of over 30 MYC-target genes, primarily those regulating amino acid and protein synthesis, including eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1), a negative regulator of translation. 4E-BP1 relieves MYC-induced proteotoxic stress and is essential to balance protein synthesis. 4E-BP1 activity is negatively regulated by mammalian target of rapamycin complex 1 (mTORC1)-dependent phosphorylation and inhibition of mTORC1 signalling rescues ATF4-deficient cells from MYC-induced endoplasmic reticulum stress. Acute deletion of ATF4 significantly delays MYC-driven tumour progression and increases survival in mouse models. Our results establish ATF4 as a cellular rheostat of MYC activity, which ensures that enhanced translation rates are compatible with survival and tumour progression

Nanofeatured Titanium Surfaces for Dental Implantology: Biological Effects, Biocompatibility, and Safety

Nanotechnology enables the control and modification of the chemical and topographical characteristics of materials of size less than 100 nm, down to 10 nm. The goal of this review is to discuss the role of titanium substrates as nanoscale surface modification tools for improving various aspects of implantology, including osseointegration and antibacterial properties. Techniques that can impart nanoscale topographical features to endosseous implants are described. Since the advent of nanotechnology, cellular specific functions, such as adhesion, proliferation, and differentiation, have been better understood. By applying these technologies, it is possible to direct cellular responses and improve osseointegration. Conversely, modulating surface features by nanotechnology could have the effect of decreased bacterial colonization

Field-induced XY behavior in the S=1/2 antiferromagnet on the square lattice

Making use of the quantum Monte Carlo method based on the worm algorithm, we study the thermodynamic behavior of the S=1/2 isotropic Heisenberg antiferromagnet on the square lattice in a uniform magnetic field varying from very small values up to the saturation value. The field is found to induce a Berezinskii-Kosterlitz-Thouless transition at a finite temperature, above which a genuine XY behavior in an extended temperature range is observed. The phase diagram of the system is drawn, and the thermodynamic behavior of the specific heat and of the uniform and staggered magnetization is discussed in sight of an experimental investigation of the field-induced XY behavior.Comment: 4 pages, 4 figure