Predictable Immediate Implant Placement and Restoration in the Esthetic Zone

This article describes a comprehensive step-by-step protocol for immediate implant placement and restoration in the esthetic zone. Clinical Considerations Immediate implant placement into fresh extraction sockets and immediate restoration have become widely accepted, demonstrating long-term success rates that are comparable with traditional delayed implant protocols. However, they are technique sensitive and require proper treatment planning as well as meticulous execution to be predictable and successful in the long term. This is particularly important in the esthetic zone, where even minor aberrations and mistakes can have devastating consequences, and especially in younger patients, where esthetic and functional outcomes should remain stable for years and possibly decades to come. The eight critical steps for predictable immediate implant placement include: provisional restoration of the failing tooth and presurgical phase, atraumatic tooth extraction, initial implant osteotomy, 3D bone graft packing, guided implant placement with a surgical guide, customized abutment insertion, provisional crown relining, and placement of a connective tissue graft from tuberosity. Immediate implant protocols in the esthetic zone require thorough planning and execution in the proper sequence. Each one of the critical steps discussed in this article has its own importance and challenges, which are critically assessed based on current scientific evidence. © 2021 Wiley Periodicals LL

Model-free two-step design for improving transient learning performance in nonlinear optimal regulator problems

Reinforcement learning (RL) provides a model-free approach to designing an optimal controller for nonlinear dynamical systems. However, the learning process requires a considerable number of trial-and-error experiments using the poorly controlled system, and accumulates wear and tear on the plant. Thus, it is desirable to maintain some degree of control performance during the learning process. In this paper, we propose a model-free two-step design approach to improve the transient learning performance of RL in an optimal regulator design problem for unknown nonlinear systems. Specifically, a linear control law pre-designed in a model-free manner is used in parallel with online RL to ensure a certain level of performance at the early stage of learning. Numerical simulations show that the proposed method improves the transient learning performance and efficiency in hyperparameter tuning of RL

Safe Exploration Method for Reinforcement Learning under Existence of Disturbance

Recent rapid developments in reinforcement learning algorithms have been giving us novel possibilities in many fields. However, due to their exploring property, we have to take the risk into consideration when we apply those algorithms to safety-critical problems especially in real environments. In this study, we deal with a safe exploration problem in reinforcement learning under the existence of disturbance. We define the safety during learning as satisfaction of the constraint conditions explicitly defined in terms of the state and propose a safe exploration method that uses partial prior knowledge of a controlled object and disturbance. The proposed method assures the satisfaction of the explicit state constraints with a pre-specified probability even if the controlled object is exposed to a stochastic disturbance following a normal distribution. As theoretical results, we introduce sufficient conditions to construct conservative inputs not containing an exploring aspect used in the proposed method and prove that the safety in the above explained sense is guaranteed with the proposed method. Furthermore, we illustrate the validity and effectiveness of the proposed method through numerical simulations of an inverted pendulum and a four-bar parallel link robot manipulator.Comment: Accepted to the European Conference on Machine Learning and Principles and Practice of Knowledge Discovery in Databases (ECMLPKDD) 202

Glycopeptoid nanospheres: glycosylation-induced coacervation of poly(sarcosine)

Conjugation of maltopentaose to water-soluble homo-poly(sarcosine) induced self-association and formed nanospheres (−150 nm) in water although homo-poly(sarcosine) was water-soluble and did not form any aggregates. Fluorescent probe experiments showed that the spheres were non-ionic glycopeptoid coacervate-like particles with both hydrophobic and hydrophilic domains inside

Cyclodextrin-responsive nanogel as an artificial chaperone for horseradish peroxidase

The thermal stabilization and refolding of horseradish peroxidase (HRP) upon heating were investigated using an artificial molecular chaperone consisting of cholesterol-bearing pullulan (CHP) nanogels. The CHP nanogels inhibited the aggregation of HRP under heating by complexation with the denatured HRP. The enzyme activity of HRP complexed with CHP nanogels was not detected. However, the enzyme activity recovered up to 80% of native HRP after the addition of cyclodextrin (CD) to the complex. The dissociation of CHP nanogels was induced by the formation of an inclusion complex of cholesterol groups of CHP with CD. The enzyme activity of HRP was only significantly recovered by the addition of β-CD or its derivatives. Natural molecular chaperones, such as GroEL/ES, trap, fold, and release the nonnative proteins by changing the hydrophobicity of the specific sites of the molecular chaperone that interact with the nonnative protein. The functional mechanism of the nanogel chaperon system is similar to that of natural molecular chaperones. The nanogel chaperone system is a useful tool to aid the refolding and thermal stabilization of unstable proteins for post-genome research, and in medical and biological applications

Household smoking and dental caries in schoolchildren: the Ryukyus Child Health Study

<p>Abstract</p> <p>Background</p> <p>Secondhand smoke exposure (SHSe) is perhaps one of the most important toxic exposures in childhood. However, epidemiological studies on the relation between SHSe and dental caries are limited and have yielded inconsistent results. The present cross-sectional study examined the potential association between SHSe at home and the prevalence of dental caries in children.</p> <p>Methods</p> <p>Subjects were 20,703 schoolchildren aged 6 to 15 years in Okinawa, Japan. Information on SHSe at home and potential confounding factors was obtained through questionnaires. Data on dental caries were obtained from school records. Children were classified as having decayed and/or filled teeth (DFT) if a dentist diagnosed these conditions. Additionally, we analyzed decayed teeth (DT) and filled teeth (FT) separately. Adjustment was made for sex, age, region of residence, toothbrushing frequency, use of fluoride, sugar intake, and paternal and maternal educational level.</p> <p>Results</p> <p>The prevalence of DFT was 82.0%. Compared with never smoking in the household, former and current household smoking were independently associated with an increased prevalence of DFT (adjusted prevalence ratios [95% confidence intervals] for former household smoking and current light and heavy household smoking were 1.03 [1.00-1.05], 1.04 [1.02-1.05], and 1.04 [1.03-1.06], respectively); when analyzed separately there was an increased prevalence of DT (adjusted prevalence ratios [95% confidence intervals] for former household smoking and current light and heavy household smoking were 1.06 [1.02-1.11], 1.10 [1.06-1.13], and 1.10 [1.07-1.14], respectively) but not FT. A statistically significant dose-response relationship between cumulative smoking in the household and the prevalence of DFT and DT (<it>P </it>for trend < 0.0001), but not FT, was observed. In an analysis of 2 subgroups, subjects who had at least 1 deciduous tooth and subjects who had at least 1 permanent tooth, household smoking exposure was associated with an increased prevalence of DFT and DT not only in those with deciduous but also those with permanent dentition.</p> <p>Conclusion</p> <p>Our findings suggested that household smoking might be associated with an increased prevalence of dental caries in children.</p