Durability of cantilever inlay-retained fixed dental prosthesis fabricated from multilayered zirconia ceramics with different designs.

PURPOSE The purpose of this in-vitro study was to investigate the effect of framework design on fracture resistance and failure modes of cantilever inlay-retained fixed partial dentures (IRFDPs) fabricated from two multilayered monolithic zirconia materials. MATERIALS AND METHODS Seventy-two natural premolar teeth were prepared as abutments for cantilever IRFDPs using three designs: mesial-occlusal (MO) inlay with short buccal and palatal wings (D1), MO inlay with long palatal wing (D2), MO inlay with long palatal wing and occlusal extension (D3). Full-contoured IRFDPs were fabricated from two monolithic zirconia materials; IPS e.max ZirCAD Prime and Zolid Gen-X. Adhesive surfaces were air-abraded and bonded with MDP-containing resin cement. Specimens were subjected to thermocycling (5-55 °C, 5000 cycles); then, mechanical loading (1.2 × 10⁶ cycles, 49 N). Surviving specimens were loaded until failure in the universal testing machine. All specimens were examined under stereomicroscope, and two samples from each group were evaluated using Scanning Electron Microscope. RESULTS Mean failure loads were not significantly different between different framework designs or between two materials. However, IPS e.max ZirCAD Prime showed significantly higher failure rate than Zolid Gen-X during dynamic fatigue (p = 0.009). Samples with D1 design showed higher debonding rate, D2 failed mainly by fracture of the palatal wing and debonding, and D3 failed mainly by fracture of the abutment tooth. Debonded restorations showed mainly mixed failures. CONCLUSION Cantilever IRFDPs with framework designs that maximize adhesion to enamel exhibited promising results. IPS e.max ZirCAD Prime was more susceptible to fractures with the long palatal wing design

Durability of cantilever inlay-retained fixed dental prosthesis fabricated from multilayered zirconia ceramics with different designs

Purpose: The purpose of this in-vitro study was to investigate the effect of framework design on fracture resistance and failure modes of cantilever inlay-retained fixed partial dentures (IRFDPs) fabricated from two multilayered monolithic zirconia materials. Materials and methods: Seventy-two natural premolar teeth were prepared as abutments for cantilever IRFDPs using three designs: mesial-occlusal (MO) inlay with short buccal and palatal wings (D1), MO inlay with long palatal wing (D2), MO inlay with long palatal wing and occlusal extension (D3). Full-contoured IRFDPs were fabricated from two monolithic zirconia materials; IPS e.max ZirCAD Prime and Zolid Gen-X. Adhesive surfaces were air-abraded and bonded with MDP-containing resin cement. Specimens were subjected to thermocycling (5-55 °C, 5000 cycles); then, mechanical loading (1.2 × 10⁶ cycles, 49 N). Surviving specimens were loaded until failure in the universal testing machine. All specimens were examined under stereomicroscope, and two samples from each group were evaluated using Scanning Electron Microscope. Results: Mean failure loads were not significantly different between different framework designs or between two materials. However, IPS e.max ZirCAD Prime showed significantly higher failure rate than Zolid Gen-X during dynamic fatigue (p = 0.009). Samples with D1 design showed higher debonding rate, D2 failed mainly by fracture of the palatal wing and debonding, and D3 failed mainly by fracture of the abutment tooth. Debonded restorations showed mainly mixed failures. Conclusion: Cantilever IRFDPs with framework designs that maximize adhesion to enamel exhibited promising results. IPS e.max ZirCAD Prime was more susceptible to fractures with the long palatal wing design

Human metapneumovirus and respiratory syncytial virus disease in children, Yemen

Factors increasing the severity of respiratory infections in developing countries are poorly described. We report factors associated with severe acute respiratory illness in Yemeni children (266 infected with respiratory syncytial virus and 66 with human metapneumovirus). Age, indoor air pollution, and incomplete vaccinations were risk factors and differed from those in industrialized countries

Multiple sampling in one day to optimize smear microscopy in children with tuberculosis in Yemen

Background and Aim The diagnosis of pulmonary Tuberculosis (TB) in children is difficult and often requires hospitalization. We explored whether the yield of specimens collected for smear microscopy from different anatomical sites in one visit is comparable to the yield of specimens collected from a single anatomical site over several days. Methodology and Principal Findings Children with signs/symptoms of pulmonary TB attending a reference hospital in Sana'a Yemen underwent one nasopharyngeal aspirate (NPA) the first day of consultation and three gastric aspirates (GA) plus three expectorated/induced sputa over 3 consecutive days. Specimens were examined using smear microscopy (Ziehl-Neelsen) and cultured in solid media (Ogawa). Two hundred and thirteen children (aged 2 months-15 years) were enrolled. One hundred and ninety seven (93%) underwent nasopharyngeal aspirates, 196 (92%) GA, 122 (57%) expectorated sputum and 88 induced sputum. A total 1309 specimens were collected requiring 237 hospitalization days. In total, 29 (13.6%) children were confirmed by culture and 18 (8.5%) by smear microscopy. The NPA identified 10 of the 18 smear-positives; three consecutive GA identified 10 and induced/expectorated sputa identified 13 (6 by induced, 8 by expectorated sputum and one positive by both). In comparison, 22 (3.7%) of 602 specimens obtained the first day were smear-positive and identified 14 (6.6%) smear-positive children. Conclusion/Significance The examination of multiple tests the first day of consultation identified a similar proportion of smear-positive children than specimens collected over several days; would require half the number of tests and significantly less hospitalization. Optimized smear microscopy approaches for children should be explored further

Towards Solutions of Seepage Problems

Flow rates are traditionally used for solving seepage problems in soils. In this paper, the method of fragments is presented as a good alternative for solving seepage problems. A user friendly and interactive computer program for the method of fragments has been developed. Several randomly selected problems are solved by the flow net method, the method of fragments and the finite difference method. It was found that the method of fragments and the finite difference method gave very close predictions of the quantity of flow, exit gradient and uplift force. Furthermore, the effects of different positions and lengths, and number of sheet piles, and upstream blankets on the values of quantity of flow, exit gradient and uplift force are examined

Respiratory syncytial virus and human metapneumovirus in children with acute respiratory infections in Yemen

A survey of 604 Yemeni children younger than 2 years with acute respiratory infections identified respiratory syncytial virus (RSV) in 244 (40%), human metapneumovirus (HMPV) in 41 (7%) and RSV/HMPV coinfection in 25 (4%) children. RSV infections occurred in younger children and were associated with more severe hypoxia than observed with HMPV. Both viruses are important causes of severe acute respiratory infection in Yemen

Micronutrient concentrations in respiratory syncytial virus and human metapneumovirus in Yemeni children

Background: Acute respiratory infections (ARI) cause significant childhood mortality. Nutritional homeostasis, particularly micronutrient levels, is important in modulating response to infection. More information is required regarding micronutrient levels in ARI viral infections, especially newly identified viruses such as human metapneumovirus (HMPV). Aim: To describe zinc, copper, selenium and vitamins A and E concentrations in children with respiratory syncytial virus (RSV) and/or HMPV in relation to levels of C-reactive protein (CRP). Methods: The presence of RSV/HMPV in nasopharyngeal aspirates (NPA) was identified in 246 children using RTPCR. Zinc, copper, selenium and vitamins A and E concentrations were measured using inductive coupled plasma mass spectrometry and high performance liquid chromatography. Results: 183 children had RSV, 39 had HMPV and 24 were co-infected. Zinc concentrations were lower in children with HMPV than in children with RSV or RSV/HMPV co-infection. Copper concentrations were lower in children with RSV than in children with RSV/ HMPV or HMPV and zinc/copper ratios were lower in children with HMPV/RSV or RSV than in children with HMPV alone. Retinol and alpha-tocopherol were lower in children with RSV than in children with HMPV. Most children had low selenium concentrations. Children with RSV and raised CRP (>5 mg/L) had higher copper and lower zinc/copper ratios than those with low CRP (<= 5 mg/L). Children with HMPV and raised CRP had higher copper and lower zinc concentrations than children with low CRP. Children with RSV/ HMPV and raised CRP had higher copper concentrations. Children with RSV/ HMPV and raised CRP had higher alpha-tocopherol concentrations. Conclusion: The profiles of micronutrients differ in children with RSV and HMPV and are confounded by CRP. These results may guide strategies for micronutrient supplementation in ARI