Root Canal Morphology of Mandibular Canine in an Iranian Population: A CBCT Assessment

Introduction: The present study was conducted to assess the morphology of mandibular canines using cone-beam computed tomography (CBCT) in a north Iranian population. Methods and Materials: For the morphological assessment of mandibular canines, 150 CBCT images taken from patients for different reasons were used. The mandibular canines were examined in sagittal, coronal and axial dimensions. The canal pattern, number of roots/canals, the tooth length, the orientation of the roots and the position of the apical foramina were evaluated and the effect of gender on each variable was assessed. The obtained data were analyzed using the Chi-square and student’s t-tests. Results: According to the Vertucci’s criteria, the most common pattern was type I morphology (89.7%), followed by types III (5.7%), II (3.7%) and V (1%). No significant differences were observed between the male and female patients in terms of canal type (P>0.05). Gender difference is a factor which affected the root length and the number of mandibular canine root and root canal. There were 296 single-root and four double-root canines. The double-root canines and mandibular canine with two canals were significantly more common among men than women (P=0.00). The apical foramen was laterally positioned in 68.3% and centrally in 31.7% of the cases, and the root curvatures were mostly oriented toward the buccal region. No significant statistical difference was observed for mentioned parameters in right and left half of the jaw. Conclusion: Due the diverse morphology and the potential presence of a second mandibular canine among Iranians, dentists should perform endodontic treatments with greater care. CBCT is an accurate tool for the morphological assessment of root canals.Keywords: Canine; Cone-Beam Computed Tomography; Root Canal

Interleukin 35 levels in saliva of type 2 diabetic patients with moderate chronic periodontitis

Introduction: Periodontitis is a common disease in patients with diabetes. There is a significant relationship between hyperglycemic degree and severity of periodontitis, but the base of mechanism of this relationship has not been fully defined. Considering the important role of cytokines in periodontal pathogenesis and considering that there has been no study on the comparison of interleukin 35 (IL-35) in these diseases, the aim of this study was to determine the level of this salivary cytokine in patients with type 2 diabetes mellitus with generalized moderate chronic periodontitis. Material & Methods: Totally, 88 subjects (44 female, 44 males) with a mean age of 42.5±10.5 years old participated in this case control study. The subjects were divided into four groups and each group included 22 subjects: Group 1: generalized moderate chronic periodontitis patients with type 2 diabetes, Group 2: generalized moderate chronic periodontitis patients without diabetes, Group 3: diabetic patients with normal periodontium, Group 4: healthy periodontium and non-diabetic group (control) Then saliva were collected and centrifuged, the amount of IL-35 was determined with commercial ELISA kit. Data were analyzed . ANOVA and Tukey post-hoc tests were used to compare the groups. Results: The Mean±SD of IL-35 was significantly higher in the control group (22.59±8.36, p0.05). Conclusion: The salivary IL-35 level is decreased in both periodontitis and type 2 diabetes. However, diabetes mellitus does not exacerbate this decline in patients with periodontitis

Resolving physical interactions between bacteria and nanotopographies with focused ion beam scanning electron microscopy

To robustly assess the antibacterial mechanisms of nanotopographies, it is critical to analyze the bacteria-nanotopography adhesion interface. Here, we utilize focused ion beam milling combined with scanning electron microscopy to generate three-dimensional reconstructions of Staphylococcus aureus or Escherichia coli interacting with nanotopographies. For the first time, 3D morphometric analysis has been exploited to quantify the intrinsic contact area between each nanostructure and the bacterial envelope, providing an objective framework from which to derive the possible antibacterial mechanisms of synthetic nanotopographies. Surfaces with nanostructure densities between 36 and 58 per μm(2) and tip diameters between 27 and 50 nm mediated envelope deformation and penetration, while surfaces with higher nanostructure densities (137 per μm(2)) induced envelope penetration and mechanical rupture, leading to marked reductions in cell volume due to cytosolic leakage. On nanotopographies with densities of 8 per μm(2) and tip diameters greater than 100 nm, bacteria predominantly adhered between nanostructures, resulting in cell impedance

Vertical Field Effect Transistor based on Graphene-WS2 Heterostructures for flexible and transparent electronics

The celebrated electronic properties of graphene have opened way for materials just one-atom-thick to be used in the post-silicon electronic era. An important milestone was the creation of heterostructures based on graphene and other two-dimensional (2D) crystals, which can be assembled in 3D stacks with atomic layer precision. These layered structures have already led to a range of fascinating physical phenomena, and also have been used in demonstrating a prototype field effect tunnelling transistor - a candidate for post-CMOS technology. The range of possible materials which could be incorporated into such stacks is very large. Indeed, there are many other materials where layers are linked by weak van der Waals forces, which can be exfoliated and combined together to create novel highly-tailored heterostructures. Here we describe a new generation of field effect vertical tunnelling transistors where 2D tungsten disulphide serves as an atomically thin barrier between two layers of either mechanically exfoliated or CVD-grown graphene. Our devices have unprecedented current modulation exceeding one million at room temperature and can also operate on transparent and flexible substrates