Wave-Vector Dependence of the Dynamics in Supercooled Metallic Liquids.

We present a detailed investigation of the wave-vector dependence of collective atomic motion in Au_{49}Cu_{26.9}Si_{16.3}Ag_{5.5}Pd_{2.3} and Pd_{42.5}Cu_{27}Ni_{9.5}P_{21} supercooled liquids close to the glass transition temperature. Using x-ray photon correlation spectroscopy in a previously uncovered spatial range of only a few interatomic distances, we show that the microscopic structural relaxation process mimics the structure and presents a marked slowing down at the main average interparticle distance. This behavior is accompanied by dramatic changes in the shape of the intermediate scattering functions, which suggest the presence of large dynamical heterogeneities at length scales corresponding to a few particle diameters. A ballisticlike mechanism of particle motion seems to govern the structural relaxation of the two systems in the highly viscous phase, likely associated with hopping of caged particles in agreement with theoretical studies.

Amalgam Alternatives: Cost-Effectiveness and Value of Information Analysis.

We aimed to assess the cost-effectiveness of amalgam alternatives-namely, incrementally placed composites (IComp), composites placed in bulk (BComp), and glass ionomer cements (GIC). In a sensitivity analysis, we also included composite inlays (CompI) and incrementally placed bulk-fills (IBComp). Moreover, the value of information (VOI) regarding the effectiveness of all strategies was determined. A mixed public-private-payer perspective in the context of Germany was adopted. Bayesian network meta-analyses were performed to yield effectiveness estimates (relative risk [RR] of failure). A 3-surfaced restoration on a permanent molar in initially 30-y-old patients was followed over patients' lifetime using a Markov model. Restorative and endodontic complications were modeled; our outcome parameter was the years of tooth retention. Costs were derived from insurance fee items. Monte Carlo microsimulations were used to estimate cost-effectiveness, cost-effectiveness acceptability, and VOI. Initially, BComp/GIC were less costly (110.11 euros) than IComp (146.82 euros) but also more prone to failures (RRs [95% credible intervals (CrI)] were 1.6 [0.8 to 3.4] for BComp and 1.3 [0.5 to 5.6] for GIC). When following patients over their lifetime, IComp was most effective (mean [SD], 41.9 [1] years) and least costly (2,076 [135] euros), hence dominating both BComp (40.5 [1] years; 2,284 [126] euros) and GIC (41.2 years; 2,177 [126] euros) in 90% of simulations. Eliminating the uncertainty around the effectiveness of the strategies was worth 3.99 euros per restoration, translating into annual economic savings of 87.8 million euros for payers. Including CompI and IBComp into our analyses had only a minimal impact, and our findings were robust in further sensitivity analyses. In conclusion, the initial savings by BComp/GIC compared with IComp are very likely to be compensated by the higher risk of failures and costs for retreatments. CompI and IBComp do not seem cost-effective. All alternatives are likely to be inferior to amalgam. The VOI was considerable, and future studies may yield significant economic benefits.

Effects of Taxing Sugar-Sweetened Beverages on Caries and Treatment Costs.

Caries increment is affected by sugar-sweetened beverage (SSB) consumption. Taxing SSBs could reduce sugar consumption and caries increment. The authors aimed to estimate the impact of a 20% SSB sales tax on caries increment and associated treatment costs (as well as the resulting tax revenue) in the context of Germany. A model-based approach was taken, estimating the effects for the German population aged 14 to 79 y over a 10-y period. Taxation was assumed to affect beverage-associated sugar consumption via empirical demand elasticities. Altered consumption affected caries increments and treatment costs, with cost estimates being calculated under the perspective of the statutory health insurance. National representative consumption and price data were used to estimate tax revenue. Microsimulations were performed to estimate health outcomes, costs, and revenue impact in different age, sex, and income groups. Implementing a 20% SSB sales tax reduced sugar consumption in nearly all male groups but in fewer female groups. The reduction was larger among younger than older individuals and among those with low income. Taxation reduced caries increment and treatment costs especially in younger (rather than older) individuals and those with low income. Over 10 y, mean (SD) net caries increments at the population level were 82.27 (1.15) million and 83.02 (1.08) million teeth at 20% and 0% SSB tax, respectively. These generated treatment costs of 2.64 (0.39) billion and 2.72 (0.35) billion euro, respectively. Additional tax revenue was 37.99 (3.41) billion euro over the 10 y. In conclusion and within the limitations of this study's perspective, database, and underlying assumptions, implementing a 20% sales tax on SSBs is likely to reduce caries increment, especially in young low-income males, thereby also reducing inequalities in the distribution of caries experience. Taxation would also reduce treatment costs. However, these reductions might be limited in the total population.

Conventional treatment, Hall Technique or immediate pulpotomy for carious primary molars: a cost-effectiveness analysis.

AIM: To compare the cost-effectiveness of three strategies for treating primary molars with cavitated carious lesions and sensible (vital), asymptomatic pulps. METHODOLOGY: Conventional excavation and restoration, Hall Technique (caries sealing using a preformed crown), and pulpotomy were compared. As the latter would not be applied to all teeth in clinical reality, decision-making under perfect information was modelled, with teeth at-risk for pulpal complications receiving immediate pulpotomy, whilst all others were treated conventionally. A Markov model was constructed and transition probabilities derived from randomized trials and systematic reviews. A carious molar in a 5-year-old child was followed until exfoliation. Cost-effectiveness was assessed within the German healthcare system using a public-payer perspective. Monte Carlo microsimulations were performed to evaluate the primary outcome, costs (in Euros) per year of tooth retention. RESULTS: Conventional treatment was least effective and more expensive than the Hall Technique. Risk-based pulpotomy was more costly, but also more effective than alternatives. Overall, the Hall Technique was most cost-effective (9.77 Euros year-1 ), followed by pulpotomy (11.75 Euros year-1 ) and conventional treatment (13.31 Euros year-1 ). For payers willing to invest >59 Euros per additional year of tooth retention, risk-based pulpotomy was most cost-effective. Providing pulpotomy to all teeth was not cost-effective. CONCLUSIONS: The Hall Technique was most cost-effective, whilst conventional treatment was least effective and more costly. Performing pulpotomy for molars at-risk of pulpal complications might be effective, but was more expensive than alternatives. Moreover, accurately predicting such pulpal complications is currently not possible. Risk-based decision-making does not necessarily reduce costs.

Detecting Proximal Secondary Caries Lesions: A Cost-effectiveness Analysis.

When choosing detection methods for secondary caries lesions, dentists need to weigh sensitivity, allowing early initiation of retreatments to avoid lesion progression, against specificity, aiming to reduce risks of false-positive diagnoses and invasive overtreatments. We assessed the cost-effectiveness of different detection methods for proximal secondary lesions using Monte Carlo microsimulations. A vital permanent molar with an occlusal-proximal restoration was simulated over the lifetime of an initially 20-y-old. Three methods were compared: biannual tactile detection, radiographic detection every 2 y, and biannual laser fluorescence detection. Methods were employed either on their own or in pairwise combinations at sensitive and specific thresholds estimated with systematically collected data. A mixed public-private payer perspective in the context of German health care was applied. Effectiveness was calculated as years of tooth retention. Net-benefit analyses were used to evaluate cost-effectiveness acceptability at different willingness-to-pay thresholds. Radiographic detection verified by tactile assessment (both at specific thresholds) was least costly (mean, 1,060 euros) but had limited effectiveness (mean retention time, 50 y). The most effective but also more costly combination was laser fluorescence detection verified by radiography, again at specific thresholds (1157 euros, 53 y, acceptable if willingness to pay >32 euro/y). In the majority of simulations, not combining detection methods or applying them at sensitive thresholds was less effective and more costly. Net benefits were not greatly altered by applying different discounting rates or using different baseline prevalence of secondary lesions. Current detection methods for secondary lesions should best be used in combination, not on their own, at specific thresholds to avoid false-positive diagnoses leading to costly and invasive overtreatment. The relevant characteristics, such as predictive value, of different methods should be assessed in longitudinal clinical studies.

Detecting and treating occlusal caries lesions: a cost-effectiveness analysis.

The health gains and costs resulting from using different caries detection strategies might not only depend on the accuracy of the used method but also the treatment emanating from its use in different populations. We compared combinations of visual-tactile, radiographic, or laser-fluorescence-based detection methods with 1 of 3 treatments (non-, micro-, and invasive treatment) initiated at different cutoffs (treating all or only dentinal lesions) in populations with low or high caries prevalence. A Markov model was constructed to follow an occlusal surface in a permanent molar in an initially 12-y-old male German patient over his lifetime. Prevalence data and transition probabilities were extracted from the literature, while validity parameters of different methods were synthesized or obtained from systematic reviews. Microsimulations were performed to analyze the model, assuming a German health care setting and a mixed public-private payer perspective. Radiographic and fluorescence-based methods led to more overtreatments, especially in populations with low prevalence. For the latter, combining visual-tactile or radiographic detection with microinvasive treatment retained teeth longest (mean 66 y) at lowest costs (329 and 332 Euro, respectively), while combining radiographic or fluorescence-based detections with invasive treatment was the least cost-effective (<60 y, >700 Euro). In populations with high prevalence, combining radiographic detection with microinvasive treatment was most cost-effective (63 y, 528 Euro), while sensitive detection methods combined with invasive treatments were again the least cost-effective (<59 y, >690 Euro). The suitability of detection methods differed significantly between populations, and the cost-effectiveness was greatly influenced by the treatment initiated after lesion detection. The accuracy of a detection method relative to a "gold standard" did not automatically convey into better health or reduced costs. Detection methods should be evaluated not only against their criterion validity but also the long-term effects resulting from their use in different populations.

Cost-effectiveness of one- and two-step incomplete and complete excavations.

The treatment of deep caries lesions carries significant risks for the integrity of the pulp and often initiates a cascade of re-interventions. Incomplete caries removal may reduce these risks and avoid or delay re-treatment. The present study analyzed the cost-effectiveness of one- and two-step incomplete as well as complete excavations. We used Markov models to simulate treatment of a molar tooth with a deep caries lesion in a 15-year-old patient. Retention of the tooth and its vitality as effectiveness measures as well as accruing costs were analyzed over the patient's lifetime. The model adopted a public-private-payer perspective within German health care. Transition probabilities were calculated based on literature reviews. Monte-Carlo microsimulations were performed with 6-month cycles. One-step incomplete excavation resulted in lower long-term costs and in longer-retained teeth and their vitality (means: 53.5 and 41.0 yrs) compared with two-step incomplete (52.5 and 37.5 yrs) and complete excavations (49.5 and 31.0 yrs), and dominated the other strategies in 70% to 100% of simulations. Regardless of the assumed willingness-to-pay ceiling value, one-step incomplete excavation had the highest probability of being cost-effective. Despite limited evidence levels of input data, we expect one-step incomplete excavation to reduce costs while retaining deeply carious teeth and their vitality for longer.

In vitro effects of amylin on carbohydrate metabolism in liver cells.

Amylin, a peptide found in pancreatic amyloid deposits, may be involved in NIDDM. The effects of biosynthetic human amylin on multiple aspects of carbohydrate metabolism were studied in freshly isolated and cultured liver cells (rat hepatocytes and HepG2 cells). Acute exposure of culture liver cells to amylin had no effect on glucose incorporation into glycogen. Amylin directly reduced glucose oxidation through the hexose monophosphate shunt. The glycolytic pathway was unaffected. Amylin stimulated both glycogenolysis and gluconeogenesis. These effects were largest at amylin concentrations of 1-10 pM. Insulin partially inhibited both of these responses. Glucagon stimulated glycogenolysis and gluconeogenesis to a similar extent as amylin but required concentrations 100- to 500-fold as high. Thus, amylin, at physiologic concentrations, can impair some aspects of glucose use in liver cells and is also capable of directly stimulating glucose production, suggesting a possible involvement of amylin in the impaired glucose disposal and elevated hepatic glucose output of NIDDM.

Preliminary observations on the effects of hyperbaric oxygen therapy on western diamondback rattlesnake (Crotalus atrox) venom poisoning in the rabbit model.

Intermittent hyperbaric oxygen therapy has been shown to reduce skeletal muscle necrosis in a compartment syndrome animal model. To study whether intermittent exposure to hyperbaric oxygen augments antivenin therapy in reducing muscle necrosis, we injected sublethal doses of Western Diamondback rattlesnake (Crotalus atrox) venom intramuscularly into the hind legs of New Zealand White rabbits. In this pilot study, the animals were divided into three treatment groups. The first group received one vial of antivenin intravenously, the second group received one vial of antivenin intravenously plus three hyperbaric oxygen treatments, and the third group received no treatments. There were no statistically significant differences among the groups. These preliminary observations suggest that muscle necrosis secondary to Crotalus atrox venom poisoning is not significantly altered either by Antivenin [Crotalidae] Polyvalent at the dose level we used or in combination with intermittent hyperbaric oxygen treatments in this rabbit model.