Evaluation of long-term dental implant success and marginal bone loss in postmenopausal women.

AIM: The aim of this study was to examine long-term implant success and marginal bone loss (MBL) of dental implants in postmenopausal women with osteoporosis/osteopenia. MATERIALS AND METHODS: Postmenopausal women who underwent dental implant treatment at least 3 years ago were divided into two study groups [Test (osteoporosis/osteopenia) Group and Control Group] according to bone mineral density (BMD) measurements. Besides clinical periodontal and radiographic examinations, any implant failures were also recorded. RESULTS: A total of 52 patients with a mean age of 59.51 ± 5.66 years (Test Group; 26 patients, mean age: 60.61; Control Group; 26 patients, mean age: 58.42) were included in the study. Implant survival rates were 96.2% and 100% with a mean follow-up 60.84 ± 22.13 and 60.07 ± 20.93 months in Test and Control Groups, respectively (P > 0.05). While peri-implant PI (plaque index) and PD (probing depth) were not different between the groups, BoP (bleeding on probing) was significantly higher in Test Group (P = 0,026). Although MBL in Test Group was higher than Control Group (0.82 ± 0,63 mm and 0.44 ± 0,33 mm respectively), the difference was not found statistically significant (P = 0.069). CONCLUSION: Within the limits of this retrospective study, it can be concluded that postmenopausal osteoporosis/osteopenia does not affect MBL and long-term implant success. The findings suggest that dental implant therapy is a reliable treatment modality in these patients to improve the quality of life by increasing function and aesthetics.

Do genetic polymorphisms affect susceptibility to periodontal disease? A literature review.

The pathogenesis of periodontal disease is not solely based on microbial dental plaque but is the result of the multifactorial and complex interaction between infection and host response. Many studies in the literature have demonstrated the differences between individuals in terms of host immune response and the presence of genetic components in numerous pathological conditions. Therefore, periodontitis may be defined as a complex genetic disorder with a phenotype formed by the genetic structure and environmental factors in the affected individual. So, determination of the genetic susceptibility profile associated with periodontitis might be very precious for developing novel diagnostic techniques and individual treatment strategies. To clarify the possible role of genetic polymorphisms in periodontal diseases, we searched PubMed for studies published on the subject since 1997 up to June 2018 and obtained data from original studies, meta analyzes, and systematic reviews. We included only case-control studies with large study populations.

Significant and variable linear polarization during the prompt optical flash of GRB 160625B.

Newly formed black holes of stellar mass launch collimated outflows (jets) of ionized matter that approach the speed of light. These outflows power prompt, brief and intense flashes of γ-rays known as γ-ray bursts (GRBs), followed by longer-lived afterglow radiation that is detected across the electromagnetic spectrum. Measuring the polarization of the observed GRB radiation provides a direct probe of the magnetic fields in the collimated jets. Rapid-response polarimetric observations of newly discovered bursts have probed the initial afterglow phase, and show that, minutes after the prompt emission has ended, the degree of linear polarization can be as high as 30 per cent-consistent with the idea that a stable, globally ordered magnetic field permeates the jet at large distances from the central source. By contrast, optical and γ-ray observations during the prompt phase have led to discordant and often controversial results, and no definitive conclusions have been reached regarding the origin of the prompt radiation or the configuration of the magnetic field. Here we report the detection of substantial (8.3 ± 0.8 per cent from our most conservative simulation), variable linear polarization of a prompt optical flash that accompanied the extremely energetic and long-lived prompt γ-ray emission from GRB 160625B. Our measurements probe the structure of the magnetic field at an early stage of the jet, closer to its central black hole, and show that the prompt phase is produced via fast-cooling synchrotron radiation in a large-scale magnetic field that is advected from the black hole and distorted by dissipation processes within the jet.

Large-displacement, hydrothermal frictional properties of DFDP-1 fault rocks, Alpine Fault, New Zealand: Implications for deep rupture propagation.

The Alpine Fault, New Zealand, is a major plate-bounding fault that accommodates 65-75% of the total relative motion between the Australian and Pacific plates. Here we present data on the hydrothermal frictional properties of Alpine Fault rocks that surround the principal slip zones (PSZ) of the Alpine Fault and those comprising the PSZ itself. The samples were retrieved from relatively shallow depths during phase 1 of the Deep Fault Drilling Project (DFDP-1) at Gaunt Creek. Simulated fault gouges were sheared at temperatures of 25, 150, 300, 450, and 600°C in order to determine the friction coefficient as well as the velocity dependence of friction. Friction remains more or less constant with changes in temperature, but a transition from velocity-strengthening behavior to velocity-weakening behavior occurs at a temperature of T = 150°C. The transition depends on the absolute value of sliding velocity as well as temperature, with the velocity-weakening region restricted to higher velocity for higher temperatures. Friction was substantially lower for low-velocity shearing (V < 0.3 µm/s) at 600°C, but no transition to normal stress independence was observed. In the framework of rate-and-state friction, earthquake nucleation is most likely at an intermediate temperature of T = 300°C. The velocity-strengthening nature of the Alpine Fault rocks at higher temperatures may pose a barrier for rupture propagation to deeper levels, limiting the possible depth extent of large earthquakes. Our results highlight the importance of strain rate in controlling frictional behavior under conditions spanning the classical brittle-plastic transition for quartzofeldspathic compositions.

Computer assisted spirometry.

Three of the most popular microcomputers, the TRS-80 Model I, the APPLE II+, and the IBM Personal Computer were connected to a spirometer for data acquisition and analysis. Simple programs were written which allow the collection, analysis and storage of the data produced during spirometry. Three examples demonstrate the relative ease for automating spirometers.