A randomised controlled trial of a nanofilled composite at three years: Did selective enamel etching have an effect?

General dental practice is increasingly being recognised as the ideal situation for the conduct of clinical trials into the longevity of restorations. The aim of this study was to investigate the survival of 75 nanofilled resin composite restorations placed in an assortment of cavities using a self-etch dentine bonding agent, in five UK dental practices by members of the UK-based practice-based research group, the PREP Panel, with half of the restorations receiving a selective enamel etch and the other half being placed using a self-etching approach. The results indicated good performance of the restorations examined, with no failures being identified and excellent surface characteristics, in terms of colour stability, minimal surface roughness and optimal anatomic form. Selective enamel etching tended to produce less marginal discolouration, although these results were not statistically significant.

Five Year Clinical Evaluation of Restorations Placed in a Low Shrinkage Stress Composite in UK General Dental Practices.

This paper evaluates the five year clinical evaluation of restorations formed in a low shrinkage stress resin composite material (3M ESPE Filtek Silorane, Seefeld, Germany) and placed in the general dental practices of five members of the PREP Panel, a group of UK practice-based researchers. Results indicated satisfactory performance of the material under evaluation, other than for marginal staining, which affected 60% of the restorations evaluated after five years, albeit with less than 10% of the circumference of the restorations being affected. CLINICAL RELEVANCE: The low shrinkage stress material, Filtek Silorane™, demonstrated good clinical performance in the majority of parameters which were assessed at five years.

Assessment of economic vulnerability to infectious disease crises.

Infectious disease crises have substantial economic impact. Yet mainstream macroeconomic forecasting rarely takes account of the risk of potential pandemics. This oversight contributes to persistent underestimation of infectious disease risk and consequent underinvestment in preparedness and response to infectious disease crises. One reason why economists fail to include economic vulnerability to infectious disease threats in their assessments is the absence of readily available and digestible input data to inform such analysis. In this Viewpoint we suggest an approach by which the global health community can help to generate such inputs, and a framework to use these inputs to assess the economic vulnerability to infectious disease crises of individual countries and regions. We argue that incorporation of these risks in influential macroeconomic analyses such as the reports from the International Monetary Fund's Article IV consultations, rating agencies and risk consultancies would simultaneously improve the quality of economic risk forecasting and reinforce individual government and donor incentives to mitigate infectious disease risks.

A Practice-Based Clinical Evaluation of a Bulk Fill Restorative Material.

OBJECTIVE: To evaluate the handling, by a group of practice-based researchers, of a recently introduced bulk fill resin-based composite restorative material, Filtek Bulk Fill Restorative (3M ESPE). METHODS: The twelve selected evaluators were sent explanatory letters, a pack of the material under investigation to use for 8 weeks, and a questionnaire. RESULTS: The evaluators rated the ease of use of the bulk fill restorative the same as the previously used posterior composite material. The provision of one shade only for evaluation may have compromised the score for aesthetic quality. No post-operative sensitivity was reported. CONCLUSIONS: The bulk fill material was well received as indicated by the high number of evaluators who would both purchase the material and recommend it to colleagues. CLINICAL REVELANCE: A recently introduced bulk fill restorative material achieved a rating for handling which was similar to the evaluators' previously used resin composite, although there were some concerns regarding the translucency of the material.

Dental materials--what goes where? Class I and II cavities.

UNLABELLED: Dental amalgam has helped maintain dental public health in the developed world for over a century. However, its days appear to be numbered. Notwithstanding the environmental consideration, there is an ever increasing demand from dental patients for non-metallic and tooth-coloured restorations in their posterior teeth. This paper gives a brief history of dental amalgam and critically appraises the alternative materials, the principal of these being resin-based composite. CLINICAL RELEVANCE: The majority of practitioners carry out large numbers of Class I and II restorations, so an appraisal of the pros and cons of the alternatives may assist in decision-making.

Whole-plant versus leaf-level regulation of photosynthetic responses after partial defoliation in Eucalyptus globulus saplings.

Increases in photosynthetic capacity (A1500) after defoliation have been attributed to changes in leaf-level biochemistry, water, and/or nutrient status. The hypothesis that transient photosynthetic responses to partial defoliation are regulated by whole-plant (e.g. source-sink relationships or changes in hydraulic conductance) rather than leaf-level mechanisms is tested here. Temporal variation in leaf-level gas exchange, chemistry, whole-plant soil-to-leaf hydraulic conductance (KP), and aboveground biomass partitioning were determined to evaluate mechanisms responsible for increases in A1500 of Eucalyptus globulus L. potted saplings. A1500 increased in response to debudding (B), partial defoliation (D), and combined B&D treatments by up to 36% at 5 weeks after treatment. Changes in leaf-level factors partly explained increases in A1500 of B and B&D treatments but not for D treatment. By week 5, saplings in B, B&D, and D treatments had similar leaf-specific KP to control trees by maintaining lower midday water potentials and higher transpiration rate per leaf area. Whole-plant source:sink ratios correlated strongly with A1500. Further, unlike KP, temporal changes in source:sink ratios tracked well with those observed for A1500. The results indicate that increases in A1500 after partial defoliation treatments were largely driven by an increased demand for assimilate by developing sinks rather than improvements in whole-plant water relations and changes in leaf-level factors. Three carbohydrates, galactional, stachyose, and, to a lesser extent, raffinose, correlated strongly with photosynthetic capacity, indicating that these sugars may function as signalling molecules in the regulation of longer term defoliation-induced gas exchange responses.

Ecophysiological responses of a young blue gum (Eucalyptus globulus) plantation to weed control.

Early weed control may improve the growth of forest plantations by influencing soil water and nutrient availability. To understand eucalypt growth responses to weed control, we examined the temporal responses of leaf gas-exchange, leaf nitrogen concentration (N) and water status of 7-month-old Eucalyptus globulus L. trees in a paired-plot field trial. In addition, we monitored the growth, leaf N and water status of the competing vegetation in the weed treatment. By the end of the 11-month experiment, complete weed control (WF treatment) of largely woody competitors increased the basal diameter of E. globulus by 14%. As indicated by pre-dawn water potentials of > - 0.05 MPa, interspecies competition for water resources was minimal at this site. In contrast, competition for N appeared to be the major factor limiting growth. Estimations of total plot leaf N (g m(-2) ground) showed that competing vegetation accounted for up to 70% of the total leaf N at the start of the trial. This value fell to 15% by the end of the trial. Despite increased leaf N(area) in WF trees 5 months after imposition of weed control, the photosynthetic capacity (A(1500)) of E. globulus was unaffected by treatment suggesting that the growth gains from weed control were largely unrelated to changes in leaf-level photosynthesis. Increased nutrient availability brought about by weed control enabled trees to increase investment into leaf-area production. Estimates of whole-tree carbon budget based on direct measurements of dark respiration and A(1500) allowed us to clearly demonstrate the importance of leaf area driving greater productivity following early weed control in a nutrient-limited site.