Effect of superspeed sintering on translucency, opalescence, microstructure, and phase fraction of multilayered 4 mol% yttria-stabilized tetragonal zirconia polycrystal and 6 mol% yttria-stabilized partially stabilized zirconia ceramics.

STATEMENT OF PROBLEM: The optical properties of recently developed multilayer zirconia have mainly been studied for the effects of conventional sintering and speed sintering but not as much for the effect of superspeed sintering. As superspeed sintering protocols typically require a higher sintering temperature and higher heating and cooling rates than speed- and conventional sintering protocols, the optical properties of superspeed sintered zirconia may be affected differently. PURPOSE: The purpose of this in vitro study was to investigate the effect of superspeed sintering on the optical properties, microstructure, and phase fraction of multilayered 4 mol% yttria-stabilized (4Y-) and 6 mol% yttria-stabilized (6Y-) zirconia. MATERIAL AND METHODS: Multilayered 4Y- and 6Y-zirconia were sectioned. After conventional and superspeed sintering, the translucency parameter (TP), and opalescence parameter (OP) were measured with a spectrophotometer (n=10). To obtain the grain sizes from the field emission scanning electron microscopy (FE-SEM) images for each layer (n=2), more than 500 (6Y-zirconia) and 800 grains (4Y-zirconia) were measured by linear intercept methods. The phase fractions were obtained through X-ray diffraction (XRD) analysis by using the Rietveld method (n=1). The results were analyzed by 3-way ANOVA and post hoc Tukey honest significant difference tests (TP and OP) and by 3-way ANOVA and post hoc Scheffé tests (grain size) (α=.05). RESULTS: No layers exhibited a significant difference in TP after superspeed sintering, except the dentin layer (DL) and transition layer 2 (T2) of 4Y- and 6Y-zirconia, respectively. The TP increased (P<.05) in DL for superspeed sintered 4Y-zirconia and decreased (P<.05) in T2 for the superspeed sintered 6Y-zirconia. However, the difference in TP by superspeed sintering was lower than the perceptibility thresholds of 50:50%. The OP decreased (P<.05) in the DL and T2 of 4Y-zirconia after superspeed sintering. For 6Y-zirconia, the OP decreased (P<.05) in all layers except for the transition layer 1 (T1) after superspeed sintering. However, the difference in OP values was minimal, with only a 1.1 difference observed for Zolid Gen-X (4Y) and a range of 1.22 to 1.62 for Katana UTML (6Y) when using superspeed sintering. No significant change was found in the grain size after superspeed sintering of either zirconia. Regardless of the sintering speed, the average grain size of the 6Y-zirconia (conventional: 2.09 to 2.21 µm; superspeed: 2.11 to 2.20 µm) was larger than that of the 4Y-zirconia (conventional: 0.50 to 0.52 µm; superspeed: 0.52 to 0.54 µm). Owing to superspeed sintering, the metastable tetragonal (T') phase content increased while the tetragonal (T) phase decreased in 4Y-zirconia; in 6Y-zirconia, the cubic (C) phase content increased, while the T'-phase content decreased. CONCLUSIONS: Superspeed sintering did not result in any clinically significant changes in the translucency and opalescence of 4Y- or 6Y-zirconia.

Effect of Cooling Rate on Mechanical Properties, Translucency, Opalescence, and Light Transmission Properties of Monolithic 4Y-TZP during Glazing.

A standard cooling rate has not been established for glazing; therefore, the effects of the cooling rate on the properties of zirconia need to be evaluated to predict outcomes in clinical practice. 4Y-TZP glazed at three different cooling rates was analyzed to estimate the effect of cooling rate during glazing on the mechanical and optical properties. Hardness tests, field-emission scanning electron microscopy analysis, X-ray diffraction analysis, flexural strength measurement, and optical property evaluations were performed. When 4Y-TZP was glazed at a higher cooling rate (Cooling-1) than the normal cooling rate (Cooling-2), there was no significant difference in grain size, flexural strength, average transmittance, and translucency parameters. The hardness was slightly reduced. The opalescence parameter was reduced for the 2.03 mm thick specimens. When 4Y-TZP was glazed at a lower cooling rate (Cooling-3) than the normal cooling rate, there was no significant difference in hardness, grain size, flexural strength, and translucency parameters. In addition, the average transmittance and opalescence parameters were slightly reduced for the 0.52 and 2.03 mm specimens, respectively. The effects of the cooling rate during glazing on the mechanical and optical properties of 4Y-TZP appear to be minimal and clinically insignificant. Therefore, even if the cooling rate cannot be strictly controlled during glazing, the clinical outcomes will not be significantly affected.

Cost-effectiveness of a 12 country-intervention to scale up short course TB preventive therapy among people living with HIV.

INTRODUCTION: In 2017, the Aurum Institute, with support from Unitaid, launched an initiative to expand short-course therapy for the prevention of tuberculosis (TB) in 12 high-burden countries. This study aimed to investigate the importance of "catalytic" effects beyond the original project timeframe when estimating cost-effectiveness of such large investments. METHODS: We estimated the cost-effectiveness of the IMPAACT4TB (I4TB) initiative from a health system perspective, using a 10-year time horizon. We first conservatively estimated costs using a "top-down" approach considering only the direct health benefits of providing TB preventive therapy to people initiating antiretroviral therapy (ART) through I4TB activities. We then re-estimated the incremental cost-effectiveness of I4TB incorporating the costs and health benefits of potential catalytic effects beyond the program itself. RESULTS: We estimated that TB preventive therapy through the I4TB initiative alone would prevent 14 201 cases of active TB and 1562 TB deaths over 10 years with an up-front investment of $52.5 million; the estimated incremental cost-effectiveness was $1580 per disability-adjusted life year (DALY) averted. If this initiative could achieve its desired catalytic effects, an additional 375 648 cases and 41 321 deaths could be averted, at an incremental cost of $546 million and cost-effectiveness of $713 per DALY averted. CONCLUSIONS: Our findings provide donors with reasonable evidence of value for money to support investment in short-course TB preventive therapy for people initiating ART in high-burden settings. Our study also illustrates the importance of considering long-term secondary ("catalytic") effects when evaluating the cost-effectiveness of large-scale initiatives designed to change a global policy landscape.

Effect of cooling rate on hardness and microstructure of Pd-Ag-In-Sn-Ga alloy during porcelain firing simulation.

This study examined the effect of the cooling rate on the hardness and its effect on the microstructure during porcelain firing simulation of a Pd-Ag-In-Sn-Ga metal-ceramic alloy. In practice, after each firing step for porcelain bonding, the prosthesis is cooled to room temperature before proceeding to the next firing step. The cooling step is known to allow the hardness of the metal substructure to increase. The aim of the study was to determine whether controlling the cooling rate after each porcelain-firing step increases the hardness of the Pd-Ag-based metal-ceramic alloy. The results showed that the hardness of specimens cooled at a higher cooling rate increased after each firing step compared to specimens cooled at a lower cooling rate (p < 0.05). During cooling after the firing simulation the InPd3-based phase of tetragonal structure precipitated from the Pd-Ag-rich matrix of the face-centered cubic structure. Hardening by cooling at a higher cooling rate after firing was the result of the coherency strains that formed at the interface of the Pd-Ag-rich matrix and the metastable phase based on the InPd3 phase. . The reduced hardness obtained in the specimen cooled at a lower cooling rate after firing resulted from the loss of coherency strains as the fine metastable phases based on the InPd3 phase were transformed into the coarser stable phase with decreased (c/a) of 0.88. This finding revealed that controlling the cooling rate during porcelain firing simulation improves the hardness of the Pd-Ag-In-Sn-Ga metal-ceramic alloy without an additional heat treatment of the alloy.

Patient-incurred cost of inpatient treatment for Tuberculosis in rural Malawi.

OBJECTIVES: To mitigate the economic burden of tuberculosis (TB), it is important to fully understand the costs of TB treatment from the patient perspective. We therefore sought to quantify the patient-incurred cost of TB treatment in rural Malawi, with specific focus on costs borne by patients requiring inpatient hospitalisation. METHODS: We conducted a cross-sectional survey of 197 inpatients and 156 outpatients being treated for TB in rural Malawi. We collected data on out-of-pocket costs and lost wages, including costs to guardians. Costs for inpatient TB treatment were estimated and compared to costs for outpatient TB treatment. We then explored the equity distribution of inpatient TB treatment cost using concentration curves. RESULTS: Despite free government services, inpatients were estimated to incur a mean of $137 (standard deviation: $147) per initial TB episode, corresponding to >50% of annual household spending among patients in the lowest expenditure quintile. Non-medical hospitalisation costs accounted for 88% of this total. Patients treated entirely as outpatients incurred estimated costs of $25 (standard deviation: $15) per episode. The concentration curves showed that, among individuals hospitalised for an initial TB episode, poorer patients shouldered a much greater proportion of inpatient TB treatment costs than wealthier ones (concentration index: -0.279). CONCLUSION: Patients hospitalised for TB in resource-limited rural Malawi experience devastating costs of TB treatment. Earlier diagnosis and treatment must be prioritised if we are to meet goals of effective TB control, avoidance of catastrophic costs and provision of appropriate patient-centred care in such settings.

OBJECTIFS: Pour atténuer la charge économique de la tuberculose (TB), il est important de bien comprendre les coûts du traitement de la TB du point de vue du patient. Nous avons donc cherché à quantifier les coûts encourus par les patients pour le traitement de la TB dans les zones rurales du Malawi, en mettant l'accent sur les coûts supportés par les patients nécessitant une hospitalisation. MÉTHODES: Nous avons mené une enquête transversale auprès de 197 patients hospitalisés et 156 patients ambulatoires traités pour la TB dans les régions rurales du Malawi. Nous avons collecté des données sur les dépenses payées directement de la poche et les pertes de salaire, y compris les coûts pour les gardiens des malades. Les coûts du traitement anti-TB des patients hospitaliser ont été estimés et comparés aux ceux des patients ambulatoires. Nous avons ensuite exploré la répartition des équités propres au coût du traitement de la TB des patients hospitalisés en utilisant des courbes de concentration. RÉSULTATS: Malgré les services gratuits du gouvernement, les patients hospitalisés encouraient en moyenne estimée de 137 $ (écart-type: 147 $) par épisode initial de TB, ce qui correspond à >50% des dépenses annuelles des ménages chez les patients du quintile de dépenses le plus bas. Les frais d'hospitalisation non médicaux représentaient 88% de ce total. Les patients traités entièrement en ambulatoire encouraient des coûts estimés à 25 $ (écart type: 15 $) par épisode. Les courbes de concentration ont montré que, parmi les personnes hospitalisées pour un premier épisode de TB, les patients les plus pauvres supportaient une proportion beaucoup plus élevée des coûts de traitement de la TB en hospitalisation que les plus riches (indice de concentration: -0,279). CONCLUSION: Les patients hospitalisés pour la TB dans les régions rurales pauvres du Malawi connaissent des coûts dévastateurs pour le traitement de la TB. Le diagnostic et le traitement précoces doivent être priorisés si nous voulons atteindre des objectifs de contrôle efficace de la TB, d'évitement des coûts catastrophiques et de prestation de soins appropriés centrés sur le patient dans de tels contextes .

Effect of ice quenching after oxidation with or without vacuum on the hardness of Pd-Ag-Au-In alloy during porcelain firing simulation.

This study examined the effect of ice-quenching after oxidation treatment with or without vacuum, on the change in the hardness of a Pd-Ag-Au-In metal-ceramic alloy during porcelain-firing simulation. The aim of the present study is to determine whether ice quenching after oxidation renders a Pd-Ag metal-ceramic alloy soft enough for easy processing without the need for an additional solution treatment and whether it affects the final hardness of the Pd-Ag metal-ceramic alloy after porcelain firing simulation. The oxidation treatment resulted in the as-cast specimen becoming homogenized, which was progressed further by vacuuming. The bench-cooling to room temperature after the oxidation resulted in precipitation. From the next firing step, the precipitation occurred during the firing process as well as subsequent bench-cooling; this was owing to the presence of a phase boundary wherein the single phase is separated into two phases between the temperatures of the oxidation treatment (1010 °C) and post-oxidation treatment (~960 °C). During the firing process until main bake, the specimen that was ice-quenched after oxidation maintained a higher hardness than the bench-cooled specimen, particularly for the oxidation treated specimen with vacuum (p < 0.05). The mechanism of ice-quenching after oxidation with vacuum to induce further hardening during the firing process involved more active precipitation; this was attributed to the further progress of homogenization during the oxidation. The precipitation reaction in the present study corresponded to the Pd-In binary phase diagram, illustrating that as the firing proceeded, the Pd3(In,Sn,Ga) phase was precipitated from the Pd-Ag-Au-rich matrix. The findings revealed that ice quenching after oxidation makes the alloy soft enough for easy processing without an additional heat treatment and does not affect the final hardness of the Pd-Ag metal-ceramic alloy after porcelain firing simulation.

Effect of ice-quenching after oxidation treatment on hardening of a Pd-Cu-Ga-Zn alloy for bonding porcelain.

This study examined the effect of ice-quenching after oxidation treatment on hardness change of a Pd-Cu-Ga-Zn metal-ceramic alloy during porcelain firing simulation. Although not statistically significant, the alloy was softened slightly during porcelain firing simulation with conventional slow cooling rate. On the other hand, the hardness increased significantly by ice-quenching instead of the slow cooling after oxidation (p<0.001). The gap in the final hardness depending on ice-quenching occurred in the matrix and plate-like precipitates but not in the particle-like structure without plate-like precipitates (p<0.05). The mechanism of ice-quenching after oxidation to prevent softening and induce hardening during porcelain firing simulation involved the more active precipitation and retardation of microstructural coarsening. In conclusion, for practical work on Pd-Cu-Ga-Zn alloys, the oxidation treatment followed by ice-quenching instead of slow cooling is recommended for the simultaneous oxidation and hardening effects on the alloy.

Effect of ice-quenching on the change in hardness of a Pd-Au-Zn alloy during porcelain firing simulation.

This study examined the effect of ice-quenching after degassing on the change in hardness of a Pd-Au-Zn alloy during porcelain firing simulations. By ice-quenching after degassing, the specimens were softened due to homogenization without the need for an additional softening heat treatment. The lowered hardness by ice-quenching after degassing was recovered greatly from the first stage of porcelain firing process by controlling the cooling rate. The increase in hardness during cooling after porcelain firing was attributed to the precipitation of the f.c.t. PdZn phase containing Au, which caused severe lattice strain in the interphase boundary between the precipitates and matrix of the f.c.c. structure. The final hardness was slightly higher in the ice-quenched specimen than in the specimen cooled at stage 0 (the most effective cooling rate for alloy hardening) after degassing. This was attributed to the more active grain interior precipitation during cooling in the ice-quenched specimen after degassing.

Perceptions about family planning and contraceptive practice in a marital dyad.

AIMS AND OBJECTIVES: To examine couple interactions to predict wives' contraceptive use as well as that of their husbands in rural Ethiopia. BACKGROUND: Previous studies stated that men's power and their preferences regarding family planning have a significant role in the adoption of contraception, as well as women's general reproductive health. Spousal communication on reproductive matters helped couples to be aware of each other's perspectives and enhanced the usage of family planning through shared decision-making. DESIGN: A cross-sectional descriptive design was used to analyse the Actor and Partner effects within the marital dyad. The study sample included 389 married couples who were recruited from households in seven enumeration areas randomly selected from Hetosa Woreda in Ethiopia. METHODS: We used a face-to-face interview survey. Data were collected between 22 October and 21 November 2010 and analysed using descriptive statistics, chi-squared test, t-test, Pearson's correlation and the Actor-Partner interdependence model. RESULTS: There were significant differences in perceptions about family planning, contraceptive knowledge and contraceptive use between wives and husbands. Wives' perceptions about family planning affected theirs as well as that of their husbands' knowledge and use of contraceptive methods. However, husbands' perceptions about family planning did not affect their knowledge and use of contraceptive methods, but did influence their wives'. CONCLUSIONS: The application of couple data enhanced our understanding of the complex interactions between wives and husbands, which may lead to novel dyadic-based interventions to improve family planning practice. RELEVANCE TO CLINICAL PRACTICE: Couples must be educated and informed not only about the adoption of contraception, but also about reproductive rights and responsibilities through changes in educational and motivational strategies.

Induction of mucosal and systemic immune responses following oral immunization of mice with Lactococcus lactis expressing human papillomavirus type 16 L1.

Human papillomavirus type 16 L1 (HPV16 L1) has shown considerable promise as a parenteral vaccine for prevention of cervical cancers. Here, we report the possibility of oral vaccination for HPV16 L1 using Lactococcus lactis (L. lactis) as a live vector. L. lactis MG1363 was transformed with two types of HPV16 L1-encoding plasmids for intracellular expression or secretion. L. lactis transformed with HPV16 L1-encoding plasmids retained biochemical lactic acid production capability. The mucosal and systemic immune responses were affected by the cellular location of expressed HPV16 L1 proteins in L. lactis. Serum IgG responses were induced after oral immunizations of L. lactis secreting HPV16 L1. Vaginal IgA immune responses were observed following oral immunization with L. lactis expressing HPV16 L1 in an intracellular form, but not with L. lactis secreting HPV16 L1. Furthermore, induction of HPV16 L1-specific mucosal immune responses was affected by immunization frequency. Six immunizations over 5 weeks were required to induce vaginal immune responses. The levels of HPV16 L1-specific vaginal IgA were maintained until 12 weeks after the first vaccination. These results suggest the feasibility of L. lactis as an oral vaccine vehicle of HPV16 L1 and demonstrate the importance of cellular loci of expressed antigen for induction of vaginal and systemic immune responses.