Radiographic Vertical Bone Loss Evaluation around Dental Implants Following One Year of Functional Loading

Objective: Vertical bone loss evaluations in the Nobel Biocare Replace® Select Tapered TM implant system in the human after one-year loading time.Materials and Methods: This retrospective cross-sectional study was performed on 31 patients (14 men, 17 women; mean age, 60.39 years) receiving 170 implants (mean, 5.48 for each patient) of Groovy and Non-groovy designs in the Nobel Biocare Replace® Select Tapered TM system. The marginal bone loss was measured at mesial and distal aspects of the implants on OPG x-rays after one-year follow-up. The data regarding the patient's gender, age, history of disease, smoking, bone type at implant location, loading time of prosthesis and implant, implant design, diameter and length were recorded by the patients'records and interview. The data were subjected to multiple linear regression and Pearson coefficient ratio regarding different factors.Results: The mean (standard deviation) distal, mesial and overall bone loss was 0.688 mm (0.851), 0.665 mm (0.849) and 0.935 mm (0.905), respectively in the studied implants. No significant differences were found regarding implant location, bone quality at the implant region, implant design and bone graft reception. In addition, no significant correlation was found between the occurred bone loss and implant diameter, length and number of usedsplints.Conclusion: Due to the criteria mentioned for implant success in term of bone loss values after one-year loading time, Noble Biocare Replace® Select Tapered TM implant system is an acceptable treatment option for implant restorations in this regard

Two-magnon bound state causes ultrafast thermally induced magnetisation switching.

There has been much interest recently in the discovery of thermally induced magnetisation switching using femtosecond laser excitation, where a ferrimagnetic system can be switched deterministically without an applied magnetic field. Experimental results suggest that the reversal occurs due to intrinsic material properties, but so far the microscopic mechanism responsible for reversal has not been identified. Using computational and analytic methods we show that the switching is caused by the excitation of two-magnon bound states, the properties of which are dependent on material factors. This discovery allows us to accurately predict the onset of switching and the identification of this mechanism will allow new classes of materials to be identified or designed for memory devices in the THz regime

All-optical switching in granular ferromagnets caused by magnetic circular dichroism

Magnetic recording using circularly polarised femto-second laser pulses is an emerging technology that would allow write speeds much faster than existing field driven methods. However, the mechanism that drives the magnetisation switching in ferromagnets is unclear. Recent theories suggest that the interaction of the light with the magnetised media induces an opto-magnetic field within the media, known as the inverse Faraday effect. Here we show that an alternative mechanism, driven by thermal excitation over the anisotropy energy barrier and a difference in the energy absorption depending on polarisation, can create a net magnetisation over a series of laser pulses in an ensemble of single domain grains. Only a small difference in the absorption is required to reach magnetisation levels observed experimentally and the model does not preclude the role of the inverse Faraday effect but removes the necessity that the opto-magnetic field is 10 s of Tesla in strength

Magnetisation switching of FePt nanoparticle recording medium by femtosecond laser pulses

Manipulation of magnetisation with ultrashort laser pulses is promising for information storage device applications. The dynamics of the magnetisation response depends on the energy transfer from the photons to the spins during the initial laser excitation. A material of special interest for magnetic storage are FePt nanoparticles, for which switching of the magnetisation with optical angular momentum was demonstrated recently. The mechanism remained unclear. Here we investigate experimentally and theoretically the all-optical switching of FePt nanoparticles. We show that the magnetisation switching is a stochastic process. We develop a complete multiscale model which allows us to optimize the number of laser shots needed to switch the magnetisation of high anisotropy FePt nanoparticles in our experiments. We conclude that only angular momentum induced optically by the inverse Faraday effect will provide switching with one single femtosecond laser pulse.EC under Contract No. 281043, FemtoSpin. The work at Greifswald University was supported by the German research foundation (DFG), projects MU MU 1780/8-1, MU 1780/10-1. Research at Göttingen University was supported via SFB 1073, Projects A2 and B1. Research at Uppsala University was supported by the Swedish Research Council (VR), the Röntgen-Ångström Cluster, the Knut and Alice Wallenberg Foundation (Contract No. 2015.0060), and Swedish National Infrastructure for Computing (SNIC). Research at Kiel University was supported by the DFG, projects MC 9/9-2, MC 9/10-2. P.N. acknowledges support from EU Horizon 2020 Framework Programme for Research and Innovation (2014-2020) under Grant Agreement No. 686056, NOVAMAG. The work in Konstanz was supported via the Center for Applied Photonics

A femtosecond twist to magnetism

Imagine being able to write magnetic information efficiently at THz data rates, creating such content using only the helicity of light. A consortium of researchers from institutes in San Diego, Nancy, Tsukuba and Kaiserslautern recently showed the feasibility of this process, using femtosecond laser pulses. In a recent issue of Science, Lambert et al.1 demonstrate all-optical helicity-dependent switching (AO-HDS) in ferromagnetic thin films with perpendicular magnetic anisotropy, [Co/Pt]n multilayers, as well as in granular recording media. Firing trains of femtosecond laser pulses while moving the laser spot across the specimen caused traces with up or down magnetization to be written when using left- or right-circularly polarized light, respectively, independently of the original magnetic state (see Figure 1)

A clinical and radiographical evaluation on the treatment of grade II furcation involvement of mandibular molars by demineralized bone matrix (Dynagraft) as compared with coronally positioned flap (CPF)

Statement of Problem: One of the problems associated with the treatment of periodontal diseases is caused through the extension of disease toward furcation area. Several techniques in Conservative, Resective and Regenerative categories have been suggested for the treatment of furcation involvement."nPurpose: The aim of this study was to compare the results of the treatment of grade II furcation involvement in mandibular molars using an allograft material named 'Dynagraft' (a type of demineralized bone matrix) and the coronally positioned flap. Materials and Methods: In this randomized controlled clinical trial study, twelve patients (9 females and 3 males), aged 25 to 40, suffering from bilaterally grade II furcation involvement of mandibular molars who referred to dental faculty Tehran University of medical Sciences, were investigated. The molars of one side were treated by Dynagraft whereas those of the opposite side underwent the CPF method. Measurements of the probing pocket depth (PPD), clinical attachment level (CAL), keratinized gingiva (KG) and horizontal probing depth (HPD) were recorded at baseline, 3 and 6 months after surgery. In order to investigate the bone radiographic changes, radiovisiography at the mentioned periods in addition to clinical investigation, were performed. For statistical analysis, Paired West was used."nResults: The mean PPD reduction three months and six months after the operation were 1.75 mm and 2.25mm, respectively in the Dynagraft (test) group whereas 1.26mm and 1.27mm in the CPF (control) group (P<0.005). The mean attachment gain three months and six months after the operation were 1.1 mm and 1.5mm respectively in the test group, and 0.2mm and 0.3mm in the control group (P<0.005). The mean KG reduction three months and six months after the operation were 0.5mm and 0.6mm respectively in the test group and those of the control group were 1.1mm and 1.1mm. The mean HPD reduction three months and six months after the operation were 1.55mm and 2mm respectively in the test group (P<0.005) and 0.55mm and 0.55mm in the control group (PO.01). Radiovisiography of the mentioned areas three months and six months after the operation confirmed the changes obtained from clinical measurements, showing appreciable reconstructive results (Bone filling) in the test group as compared with the control group. Moreover, root resorption was not observed."nConclusion: Based on the results of this study, Dynagraft can be used as an appropriate material in the treatment of grade II furcation involvement in mandibular molars. However, for a through evaluation of such regenerative techniques in furcation involvement, further studies with larger population and long term follow up in addition to histologic studies are suggested