Structure of the icosahedral Ti-Zr-Ni quasicrystal

The atomic structure of the icosahedral Ti-Zr-Ni quasicrystal is determined by invoking similarities to periodic crystalline phases, diffraction data and the results from ab initio calculations. The structure is modeled by decorations of the canonical cell tiling geometry. The initial decoration model is based on the structure of the Frank-Kasper phase W-TiZrNi, the 1/1 approximant structure of the quasicrystal. The decoration model is optimized using a new method of structural analysis combining a least-squares refinement of diffraction data with results from ab initio calculations. The resulting structural model of icosahedral Ti-Zr-Ni is interpreted as a simple decoration rule and structural details are discussed.Comment: 12 pages, 8 figure

Endoscopic evaluation of the bone-added osteotome sinus floor elevation procedure

Sinus floor augmentation using the bone-added osteotome technique (BAOSFE) has been advocated as a predictable procedure when initial residual bone height is 4-6mm. In this report, 16 Osseotite implants were placed using the BAOSFE procedure in eight patients under endoscopic control. Intraoperative graft positioning, potential displacement of the graft material, Schneiderian membrane integrity and distension pattern were evaluated. A small-sized perforation of the sinus membrane was visualized during sinuscopic monitoring in two implant sites without significant loss of graft material confinement. Membrane vertical distension was restricted to the area surrounding the implant apices in four implant sites while a larger detachment of the membrane enfolding the implant tips, the in-between and circumferantial areas was observed in the remaining 12 sites. The two perforated sites demonstrated a localized vertical pattern of membrane distension limited to implant apices. None of the cases complicated by perforation showed clinical signs of ongoing sinus pathology throughout the follow-up period. This limited report suggests that: (1) the BAOSFE procedure in combination with implant placement yields various patterns of sinus membrane elevation; (2) potential membrane perforation may be expected when distension follows a localized vertical augmentation pattern; and (3) small membrane perforations during the BAOSFE procedure are compatible with clinically healthy postoperative sinus conditions

Fit Accuracy of Pressed and Milled Lithium Disilicate Inlays Fabricated From Conventional Impressions or a Laboratory-Based Digital Workflow

PURPOSE The impact of material on the adaptation of lithium disilicate inlays is poorly documented. This in vitro study aims at comparing the fit accuracy of pressed and milled inlays obtained from conventional impression and laboratory-based computer-aided design and computer-aided manufacturing. MATERIAL AND METHODS A typodont molar was prepared for a mesio-occlusal ceramic inlay. The stone die generated from one conventional impression was scanned once using a laboratory scanner and the same design was used to produce 15 pressed lithium disilicate inlays from milled wax patterns (group CIDW), and 15 inlays from lithium disilicate blanks (group CICAD) with a 5-axis milling machine. Marginal and internal discrepancies were measured using the replica technique. Mixed-model ANOVA was applied to assess differences according to material and gap location at P⟨0.05. RESULTS Material and discrepancy location had a significant effect on fit measurements. Group CIDW showed significantly smaller marginal (37.4 μm) and internal (69.2 μm) discrepancies than group CICAD (59.6 μm and 93.7 μm respectively). Marginal discrepancies were significantly smaller than internal discrepancies within both groups. CONCLUSIONS Pressed inlays generated from conventional impression and milled wax patterns yielded better fit accuracy than milled inlays obtained from conventional impression and subtractive manufacturing

Effect of EDTA root conditioning on the healing of intrabony defects treated with an enamel matrix protein derivative.

Contains fulltext : 49580.pdf (publisher's version ) (Open Access)BACKGROUND: Regenerative periodontal therapy with an enamel matrix protein derivative (EMD) has been shown to promote regeneration in intrabony periodontal defects. However, in most clinical studies, root surface conditioning with EDTA was performed in conjunction with the application of EMD, and, therefore, it cannot be excluded that the results may also be attributable to the effect of the root conditioning procedure. The purpose of this study was to determine the effect of root conditioning on the healing of intrabony defects treated with EMD. METHODS: Twenty-four patients, each of whom exhibited one deep intrabony defect, were randomly treated with either open flap debridement (OFD) followed by root surface conditioning with EDTA and application of EMD (OFD+EDTA+EMD) or with OFD and application of EMD only (OFD+EMD). The following parameters were recorded at baseline and at 1 year: plaque index (PI), gingival index (GI), bleeding on probing (BOP), probing depth (PD), and clinical attachment level (CAL). RESULTS: No differences in any of the investigated parameters were observed at baseline between the two groups. Healing was uneventful in all patients. At 1 year after therapy, the OFD+EDTA+EMD group showed a reduction in mean PD from 9.3+/-1.3 mm to 4.0+/-0.9 mm (P<0.001), and mean CAL changed from 10.8+/-2.2 mm to 7.1+/-2.8 mm (P<0.001). In the OFD+EMD group, mean PD was reduced from 9.3+/-1.2 mm to 4.2+/-0.9 mm (P<0.001), and a change in mean CAL from 11.0+/-1.7 mm to 7.3+/-1.6 mm (P<0.001). There were no significant differences in any of the investigated parameters between the two groups. CONCLUSION: In intrabony defects, regenerative surgery including OFD+EDTA+EMD failed to show statistically significant differences in terms of PD reduction and CAL gain compared to treatment with OFD+EMD

Pharmacologic therapies in patients with exacerbation of chronic obstructive pulmonary disease: A systematic review with meta-analysis

Background: Chronic obstructive pulmonary disease (COPD) is characterized by frequent exacerbations. Purpose: To evaluate the comparative effectiveness and adverse events (AEs) of pharmacologic interventions for adults with exacerbation of COPD. Data Sources: English-language searches of several bibliographic sources from database inception to 2 January 2019. Study Selection: 68 randomized controlled trials that enrolled adults with exacerbation of COPD treated in out- or inpatient settings other than intensive care and compared pharmacologic therapies with placebo, "usual care," or other pharmacologic interventions. Data Extraction: Two reviewers independently extracted data and rated study quality and strength of evidence (SOE). Data Synthesis: Compared with placebo or management without antibiotics, antibiotics given for 3 to 14 days were associated with increased exacerbation resolution at the end of the intervention (odds ratio [OR], 2.03 [95% CI, 1.47 to 2.80]; moderate SOE) and less treatment failure at the end of the intervention (OR, 0.54 [CI, 0.34 to 0.86]; moderate SOE), independent of severity of exacerbations in out- and inpatients. Compared with placebo in out- and inpatients, systemic corticosteroids given for 9 to 56 days were associated with less treatment failure at the end of the intervention (OR, 0.01 [CI, 0.00 to 0.13]; low SOE) but also with a higher number of total and endocrine-related AEs. Compared with placebo or usual care in inpatients, other pharmacologic interventions (aminophyllines, magnesium sulfate, anti-inflammatory agents, inhaled corticosteroids, and shortacting bronchodilators) had insufficient evidence, showing either no or inconclusive effects (with the exception of the mucolytic erdosteine) or improvement only in lung function. Limitation: Scant evidence for many interventions; several studies had unclear or high risk of bias and inadequate reporting of AEs. Conclusion: Antibiotics and systemic corticosteroids reduce treatment failure in adults with mild to severe exacerbation of COPD