50 research outputs found

    The Incremental Cooperative Design of Preventive Healthcare Networks

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    This document is the Accepted Manuscript version of the following article: Soheil Davari, 'The incremental cooperative design of preventive healthcare networks', Annals of Operations Research, first published online 27 June 2017. Under embargo. Embargo end date: 27 June 2018. The final publication is available at Springer via http://dx.doi.org/10.1007/s10479-017-2569-1.In the Preventive Healthcare Network Design Problem (PHNDP), one seeks to locate facilities in a way that the uptake of services is maximised given certain constraints such as congestion considerations. We introduce the incremental and cooperative version of the problem, IC-PHNDP for short, in which facilities are added incrementally to the network (one at a time), contributing to the service levels. We first develop a general non-linear model of this problem and then present a method to make it linear. As the problem is of a combinatorial nature, an efficient Variable Neighbourhood Search (VNS) algorithm is proposed to solve it. In order to gain insight into the problem, the computational studies were performed with randomly generated instances of different settings. Results clearly show that VNS performs well in solving IC-PHNDP with errors not more than 1.54%.Peer reviewe

    Evaluation of the efficacy of dentin hypersensitivity treatments - a systematic review and follow-up analysis

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    OBJECTIVES: To compare the treatments used to treat dentin hypersensitivity (DH), based on its efficacy and effect duration. METHODS: Medline/PubMed, Cochrane Library, EMBASE, and ClinicalTrials were searched for articles published between January 1st , 2008 and November 14th , 2018, in English, Portuguese or Spanish, reporting clinical trials, completed and with results. This systematic review protocol was registered in PROSPERO, number CRD42019121986. RESULTS: 74 randomized clinical trials were included in the systematic review, reporting patients from 16 to 65 years old, with a clinical diagnosis of DH, that evaluate the efficacy of a desensitizing product, compared to pre-treatment, used the evaporative method stimulation and the visual analogue scale. These studies evaluated 5366 patients and at least 9167 teeth. Seven follow-up periods were considered corresponding to an immediate, medium or long-time effect. 66 studies were included in the quantitative synthesis. Glutaraldehyde with HEMA, glass ionomer cements and Laser present significant immediate (until 7 days) DH reduction. Medium term (until 1 month) reduction was observed in stannous fluoride, glutaraldehyde with HEMA, hydroxyapatite, glass ionomer cements and Laser groups. Finally, long term significant reduction was seen at potassium nitrate, arginine, glutaraldehyde with HEMA, hydroxyapatite, adhesive systems, glass ionomer cements, and LASER. CONCLUSIONS: All active ingredients show efficacy in DH reduction in different follow-up times. Only in-office treatments are effective in immediate DH reduction, maintaining its efficacy over time. For long time effects, at home treatments can also be used. More standardized evaluation protocols should be implemented to increase the robustly of the results.info:eu-repo/semantics/publishedVersio

    Global patient outcomes after elective surgery: prospective cohort study in 27 low-, middle- and high-income countries.

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    BACKGROUND: As global initiatives increase patient access to surgical treatments, there remains a need to understand the adverse effects of surgery and define appropriate levels of perioperative care. METHODS: We designed a prospective international 7-day cohort study of outcomes following elective adult inpatient surgery in 27 countries. The primary outcome was in-hospital complications. Secondary outcomes were death following a complication (failure to rescue) and death in hospital. Process measures were admission to critical care immediately after surgery or to treat a complication and duration of hospital stay. A single definition of critical care was used for all countries. RESULTS: A total of 474 hospitals in 19 high-, 7 middle- and 1 low-income country were included in the primary analysis. Data included 44 814 patients with a median hospital stay of 4 (range 2-7) days. A total of 7508 patients (16.8%) developed one or more postoperative complication and 207 died (0.5%). The overall mortality among patients who developed complications was 2.8%. Mortality following complications ranged from 2.4% for pulmonary embolism to 43.9% for cardiac arrest. A total of 4360 (9.7%) patients were admitted to a critical care unit as routine immediately after surgery, of whom 2198 (50.4%) developed a complication, with 105 (2.4%) deaths. A total of 1233 patients (16.4%) were admitted to a critical care unit to treat complications, with 119 (9.7%) deaths. Despite lower baseline risk, outcomes were similar in low- and middle-income compared with high-income countries. CONCLUSIONS: Poor patient outcomes are common after inpatient surgery. Global initiatives to increase access to surgical treatments should also address the need for safe perioperative care. STUDY REGISTRATION: ISRCTN5181700

    Building a Digital Wind Farm

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    Cuspal Fracture Resistance of Maxillary Premolar Teeth Restored With 5 Different Techniques

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    Introduction:Various methods are applied in order to restore maxillary premolar teeth which show much decay, though some inconsistencies have been reported in regard with the rate of fracture strength in different studies. Therefore, in this study, fracture resistance of buccal cusp was compared via 5 different types of restorations. Methods: In this experimental study, 75 intact extracted maxillary premolars were used and divided into 5 groups. Standard MOD cavity with reduction of pulpal cusp was prepared in all groups and then was restored with different methods. The teeth were randomly divided into Group A: amalgam build-up with one pin, Group B: amalgam build-up with two pins, Group C: composite build-up , Group D: composite build-up with fiber(FRC) and Group E: ceramic onlay. The specimen were assessed via Universal Testing Machine in order to examine fracture resistance. In order to analyze the study data, Mann- Whitny and Kruskal Wallis tests were utilized to make the comparison among five types of materials. Results:There was a high significant difference among all the groups. The average fracture resistance values were as follows: group A 236.19 N, group B 289.81 N, group C 333.07 N, group D 459.31 N and group E 165.04 N. Conclusion: Regarding the higher cuspal fracture resistance in group D, it can be definitely possible to apply this method to restore destructed and carious maxillary premolar teeth with more reliability

    Effect of Drying Time and Temperature of Solvent Evaporation of two Total Etch Adhesives on Microtensile Bond Strength of Composite to Dentin

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    Introduction: Effect of drying time and temperature of solvent evaporation were different in different studies. Therefore, the aim of this study was to investigate the appropriate drying temperature and time of solvent evaporation in the two adhesives of Etch and Rinse. Methods: Seventy-two sound third molars were collected. On the buccal surface of the crown, flat dentinal surfaces were created and bonded with two step Etch and Rinse adhesives: Adper single bond2 (ethanol/water-based) and Prime and Bond2.1 (acetone-based). Solvents were evaporated for 2s, 5s or 10s at either 21℃ or 37℃ prior to light activation (10s) and composite buildups were constructed incrementally. After storage in 37℃ water for 24 hours, the specimens were prepared for microtensile bond strength and were tested at 1 mm/min crosshead speed. Moreover, the study data were analyzed via T-test as well as one-way ANOVA and three-way ANOVA. Results: The Prime and Bond2.01 group had significantly higher bond strength compared to Adper single bond group (p=0.00). The temperature of solvent evaporation from 2s to 5s in Prime and Bond 2.01 demonstrated upper results. Temperature of solvent evaporation did not affect the microtensile bond strength of both adhesive. Conclusion: Temperature of air for evaporation of solvent did not affect microtensile bond strength. In addition, the study results indicated that the effect of time in two groups was different

    Effect of an Indirect Composite Resin Surface Treatment with Two Types of Lasers: Nd: YAG, Er:YAG and Acid Etching on the Microshear Bond Strength of a Resin Cement

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    Introduction: In order to increase the bonding strength of the composite resin cements to the indirect composites, experiments such as the creation of surface roughness with sandblasting, acid-etching, silane application, laser, etc. have been carried out. However, there is no consensus about the results. Therefore, the purpose of this study was to investigate the effect of Er: YAG and Nd: YAG lasers and acid etching on microshear bond strength of an indirect composite resin. Methods: After making 30 blocks of Gradia indirect composite (GC/Japan), three groups were considered (10 each): A(Er:YAG), B(Nd:YAG) and C (control, without interfering laser). Phosphoric acid (40%) was applied on half of the subjects in each group. Thereafter, 4 columns of the Panavia F2 resin cement were made on top of each block of composite. The micro-shear bond strength rates were examined by MTD-500(SD Mechatronik-Germany )with the cross head speed of 1mm/min). The data were analyzed by the t-test, one way /two-way ANOVA and the Post-Hoc analyses. Results: There was a significant increase in the bond strength in the laser groups, Er:YAG(P: 0.01) and Nd: YAG(P: 0.01), compared with the control group(P:0.94). The lasers alone (P<0.001) and the combination of the laser and acid-etching (P: 0.001) had significant effects. Overall, the effect of Er:YAG without acid-etching was more than all the other groups. Conclusion: The two Er:YAG and Nd: YAG lasers increased the bond strength. Though etching alone had no significant effect, the application of the laser Nd:YAG with etching increased the bond strength

    Microleakage Comparison of Polyacid Composite Resin Restorations and Resin Modified Glass Ionomer Before and After Ultrasonic Scaling

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    Introduction: In different investigations, the destructive effect of ultrasonic scalers on the margins of composites has been studied, but there are very few studies on the effects of ultrasonic scalers on the microleakage of poly-acid modified composite resin and resin modified glass ionomers. The main purpose of this study was to evaluate the marginal microleakage of class V preparations restored with resin modified glass ionomer and poly-acid modified composite resin before and after scaling with an ultrasonic scaler. Methods: This in vitro study was performed on 160 premolar teeth. Standard class V cavities were prepared on the buccal surfaces of the selected teeth. Occlusal and cervical margins were placed entirely in enamel and cementum, respectively. Teeth were randomly divided to two groups of eighty, each. For one half of each group, (40 teeth) resin modified glass ionomer and for the other half, polyacid modified composite resin was used. Each one of the binary groups was subdivided to two groups. First subgroup was restored with Fuji II Lc (Fuji Japan) and Vitremer (3M USA ) and the second subgroup was restored with F2000 compomer (3M USA) and Compoglass(Vivadent Germany). For bonding to enamel, dentinte,cementum Singlebond (3M USA) and Adhese 2 (Vivadent Germany) were used and all of the restorations were done according to instructions of the manufacturers. In ten teeth of each group, ultrasonic scaling was done and in the other ten teeth, scaling was not done. After that, all of the teeth were thermocycled and immersed in fuschin. After cutting the microleakage was evaluated. The data was analyzed by Mann – Whitney, Kruskal – Wallis and Wilcoxon tests and significant border was 0.05 . Results: The results showed that the degree of microleakage in enamel margins of poly –acid modified resin composites was lower than resin modified glass ionomers and in all groups and subgroups, the microleakage in enamel and cementum after scaling was significantly more than the groups without scaling. Conclusion: Use of resin modified glass ionomers in class V restorations has no advantages over polyacid modified composite resins
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