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Background Cervical carious lesions present a clinical challenge due to several factors and require restorative materials with optimal performance. This trial evaluated the clinical performance and cost-effectiveness of low-shrinkage giomer resin composite (LS-GRC) compared to resin-modified glass ionomer (RMGI) for restoring cervical carious lesions over a 12-month period. Participants and methods A total of 56 class V cavities were randomly assigned to two groups ( n  = 28). Intervention group received LS-GRC (Beautifil II LS, Shofu Dental Corporation, Kyoto, Japan), and control group received RMGI (Fuji II LC, GC Corporation, Tokyo, Japan). Restorations were evaluated using revised FDI criteria at baseline, 6, and 12 months. Data were statistically analyzed with a significance level of P  ≤ 0.05. Intergroup comparisons were assessed with Chi-squared test, while intragroup comparisons were assessed with Cochran’s Q test. Incremental cost-effectiveness ratio (ICER) and cost per success ratio (CPSR) were used for cost-effectiveness analysis. Results After 12 months, intergroup comparisons revealed no significant differences for all outcomes ( P  > 0.05), except for surface luster and texture, which favored LS-GRC ( P  < 0.05). Intragroup comparisons revealed no significant differences within LS-GRC group ( P  > 0.016), while within RMGI group, significant differences were observed for surface luster and texture after 12 months ( P  < 0.016). ICER analysis showed that the cost for each additional 1% improvement in clinical outcomes with LS-GRC was approximately 1.6 times higher than that of RMGI. The CPSR for LS-GRC was 4.6% lower than that of RMGI, indicating that, despite its higher initial cost, LS-GRC provided comparable clinical performance, with significantly improved esthetic surface quality and favorable cost-effectiveness over the 12-month period. Conclusions LS-GRC and RMGI exhibited comparable performance and were clinically acceptable after 12 months. Clinical relevance Low-shrinkage giomer resin composite offers bioactivity, superior restoration integrity, and excellent esthetics, helping achieve optimal cervical restorations with improved clinical success, durability, and sustained cost-effectiveness. Trial registration https://clinicaltrials.gov/ , (NCT05930548), 30–06–2023. Graphical Abstract

The cementation of indirect restoration is one of the most important steps in prosthetic and restorative dentistry. Cementation aims to bond the prosthetic restoration to the prepared enamel or enamel and dentine. Successful cementation protocols prevent biofilm formation at the margin between tooth and restoration and minimize mechanical and biological complications. With the advancements in dental cements, they have been modified to be versatile in terms of handling, curing, and bond strengths. This review presents updates on dental cements, focusing on the composition, properties, advantages, limitations, and indications of the various cements available. Currently, dental restorations are made from various biomaterials, and depending on each clinical case, an appropriate luting material will be selected. There is no luting material that can be universally used. Therefore, it is important to distinguish the physical, mechanical, and biological properties of luting materials in order to identify the best options for each case. Nowadays, the most commonly used dental cements are glass-ionomer and resin cement. The type, shade, thickness of resin cement and the shade of the ceramic, all together, have a tangible influence on the final restoration color. Surface treatments of the restoration increase the microtensile bond strength. Hence, the proper surface treatment protocol of both the substrate and restoration surfaces is needed before cementation. Additionally, the manufacturer’s instructions for the thin cement-layer thickness are important for the long-term success of the restoration.

Background This study was carried out as a prospective clinical field study with the aim of evaluating the clinical performance of Equia Fil® with a nanofilled resin coating and the conventional Fuji IX GP® fast with an LC coating according to the World Dental Federation (FDI) restoration material evaluation criteria. Methods The clinical performance of Equia Fil® and Fuji IX GP® fast was evaluated on permanent posterior teeth of 643 adult patients aged between 20 to 80 years old in randomly selected clinics across Germany. Occlusal cavities in posterior permanent teeth were restored with Equia Fil® with a nanofilled, light-cured resin coating ( n  = 515) and Fuji IX GP® fast with an LC coating ( n  = 486). Direct clinical assessment as well as photographic assessment and assessment of stone casts of the restorations were made at 1 year, 2 years, 3 years, and 4 years. Results In 4 years, a total of 1001 fillings from both materials were placed by 111 dentists in 643 patients. Random slope models showed that the Equia filling system had overall lower odds of obtaining a delta event (material needs replacement) in comparison to Fuji IX GP® fast with an LC coating within all models. In both materials, filling size/surface was the most important component affecting the clinical performance of the materials. When measuring the odds of obtaining a delta event (material needs replacement), the odds ratios jumped to approximately 43 and 296 times for class II (two surfaces) and class II mesial-occlusal-distal (three surfaces) respectively in comparison to class I fillings. Conclusion Both materials showed similar good overall performance in class I cavities; however, when including numbers from both class I and II fillings, the Equia system with a nanofilled resin coating showed better overall performance with fewer failures in all the follow-up intervals. Nonetheless, the percentage of unsatisfactory to poor fillings according to the FDI criteria was relatively high in two-surface class II fillings and higher in three-surface class II fillings for both materials. Trial registration Deutsches Register Klinischer Studien (German Clinical Trials Register): DRKS00004220. ( www.germanctr.de ). Registration date: 6 Sept 2012.

The reduction of Pt content in the cathode for proton exchange membrane fuel cells is highly desirable to lower their costs. However, lowering the Pt loading of the cathodic electrode leads to high voltage losses. These voltage losses are known to originate from the mass transport resistance of O 2 through the platinum–ionomer interface, the location of the Pt particle with respect to the carbon support and the supports’ structures. In this study, we present a new Pt catalyst/support design that substantially reduces local oxygen-related mass transport resistance. The use of chemically modified carbon supports with tailored porosity enabled controlled deposition of Pt nanoparticles on the outer and inner surface of the support particles. This resulted in an unprecedented uniform coverage of the ionomer over the high surface-area carbon supports, especially under dry operating conditions. Consequently, the present catalyst design exhibits previously unachieved fuel cell power densities in addition to high stability under voltage cycling. Thanks to the Coulombic interaction between the ionomer and N groups on the carbon support, homogeneous ionomer distribution and reproducibility during ink manufacturing process is ensured. Reducing Pt content in cathodes for proton exchange membrane fuel cells is crucial to lower costs but results in high voltage losses. A Pt catalyst/support design that substantially reduces local oxygen-related mass transport resistance is reported.

Background The survival of ART restorations can be influenced by the choice of the restorative material. The aim of this randomized non-inferiority controlled trial was to compare the 2-year survival rate and cost analysis of two encapsulated glass ionomer cements (GIC) as occlusoproximal restorative materials in primary molars. Methods Children from public schools in Tietê (Brazil), aged 4–8 years with occlusoproximal dentine carious lesions in primary molars were selected and randomly assigned to receive either Equia Forte (EF) or Riva Self Cure (RSC) as restorative materials. Treatment was carried out by two trained final-year dental students in schools following ART premises. Restorations were assessed by a trained and calibrated examiner after 2, 6, 12, 18, and 24 months. The primary outcome was restoration survival after 2 years, analyzed using Kaplan-Meier survival and Cox regression analysis (α = 5%). Professional and materials costs for each group were collected in Brazilian Reais (R$) and converted into US dollars (US$) and analyzed using Monte-Carlo simulation. Results A total of 152 children (76 per group) were included in the study, and 121 (79%) were evaluated after 2 years. The overall 2-year restoration survival rate was 39% (EF = 45%; RSC = 32%) with no difference between the groups. The baseline and 2-year total cost of restorations using RSC was lower when compared to EF (incremental cost: US$ 6.18). Conclusion After two years of follow-up, Riva Self Cure shows comparable restoration survival rates to Equia Forte, being more cost-effective in the Brazilian perspective. Trial Registration This randomized clinical trial was registered on ClinicalTrials.Gov - NCT02730000.

Background Pit and fissure sealant is a micro-invasive modality for treating deep and retentive pits and fissures to prevent and/or stop occlusal caries. Every effort needs to be done to enhance sealant retention and survival. The aim of this research is to assess the retention rate of giomer S-PRG filler containing pit and fissure sealant applied with or without etching. Methods Overall, 52 patients were included in this trial and they were allocated randomly in 2 groups ( n  = 26). Group 1 (control group) received giomer sealant (Beautisealant, Shofu, Kyoto, Japan) without an etching step, and group 2 (intervention group) received the same but with a separate preparatory etching step before the sealant application. The retention rate of the sealant was assessed over one year at 3 months, 6 months, and 12 months. Intergroup comparison between categorical variables was done using the chi square test, while intragroup comparison was done using Cochran’s q test followed by multiple comparisons. Relative risk was used to evaluate the clinical significance. Survival rate was analyzed using Kaplan-meier and Log-rank test. Results Intergroup comparison between both techniques revealed statistically significant difference within different follow up periods ( P  < 0.05). Intragroup comparison within both giomer sealant with etching group and giomer sealant without etching group revealed statistically significant difference between different follow-up periods ( P  < 0.001). There was 69% less risk for total loss or partial loss of giomer sealant with etching when compared to giomer sealant without etching after 12 months. Conclusion An initial preparatory step of etching to the enamel surface is crucial before giomer sealant application to enhance its bonding, increase its retention and promote its survival. Trial registration Trial registration ClinicalTrials.gov, NCT04929782. Registered 14 July 2024 - Retrospectively registered, https://clinicaltrials.gov/study/NCT06509451

Electrolysis offers an attractive route to upgrade greenhouse gases such as carbon dioxide (CO2) to valuable fuels and feedstocks; however, productivity is often limited by gas diffusion through a liquid electrolyte to the surface of the catalyst. Here, we present a catalyst:ionomer bulk heterojunction (CIBH) architecture that decouples gas, ion, and electron transport. The CIBH comprises a metal and a superfine ionomer layer with hydrophobic and hydrophilic functionalities that extend gas and ion transport from tens of nanometers to the micrometer scale. By applying this design strategy, we achieved CO2 electroreduction on copper in 7 M potassium hydroxide electrolyte (pH ≈ 15) with an ethylene partial current density of 1.3 amperes per square centimeter at 45% cathodic energy efficiency.

Low-cost anion exchange membrane fuel cells have been investigated as a promising alternative to proton exchange membrane fuel cells for the last decade. The major barriers to the viability of anion exchange membrane fuel cells are their unsatisfactory key components—anion exchange ionomers and membranes. Here, we present a series of durable poly(fluorenyl aryl piperidinium) ionomers and membranes where the membranes possess high OH − conductivity of 208 mS cm −1 at 80 °C, low H 2 permeability, excellent mechanical properties (84.5 MPa TS), and 2000 h ex-situ durability in 1 M NaOH at 80 °C, while the ionomers have high water vapor permeability and low phenyl adsorption. Based on our rational design of poly(fluorenyl aryl piperidinium) membranes and ionomers, we demonstrate alkaline fuel cell performances of 2.34 W cm −2 in H 2 -O 2 and 1.25 W cm −2 in H 2 -air (CO 2 -free) at 80 °C. The present cells can be operated stably under a 0.2 A cm −2 current density for ~200 h. Developing high-performance anion exchange membranes and ionomers is crucial for low-cost alkaline fuel cells. Here, the authors explore rigid and high ion conductive poly(fluorenyl aryl piperidinium) copolymers, extending their applications to anion exchange membrane fuel cells.

Objective To evaluate the effect of various surface coating methods on surface roughness, micromorphological analysis and fluoride release from contemporary resin-modified and conventional glass ionomer restorations. Materials & methods A total of 72 permanent human molars were used in this study. The teeth were randomly assigned into 2 groups according to type of restorative materials used; resin modified glass ionomer cement and conventional glass ionomer (SDI Limited. Bayswater Victoria, Australia). Each group was subdivided into 3 subgroups according to the application of coat material; Sub-group1: without application of coat; Sub-group2: manufacturer recommended coat was applied and sub-group3: customized (vaseline) coat was applied. Each group was then subdivided into two divisions according to the time of testing; immediate (after 24 h) and delayed (after 6 months of storage). Three specimens from each sub-group were selected for surface roughness test (AFM) and another 3 specimens for the micromorphological analysis using scanning electron microscope (SEM). For the fluoride release test, a total of 60 cylindrical discs were used ( n  = 60). The discs were randomly split into 2 groups according to type of restorative materials used ( n  = 30); resin modified glass ionomer cement and conventional glass ionomer. Each group was subdivided into 3 subgroups ( n  = 10) according to the application of the coat material; Sub-group1: without application of coat; Sub-group2: with the manufacturer recommended coat and sub-group3: with application of customized (vaseline) coat. Data for each test was then collected, tabulated, were collected, tabulated, and tested for the normality with Shapiro-Wilk test. Based on the outcome of normality test, the significant effects of variables were assessed using appropriate statistical analysis testing methods. Results Regarding the data obtained from surface roughness test, Shapiro-Wilk test showed normal distribution pattern of all values ( p  > 0.05). Accordingly, Two-way ANOVA outcome showed that the ‘type of restoration’ or ‘test time’ had statistically significant effect on the AFM test ( p  < 0.05). Regarding Fluoride specific ion electrode test 2-way ANOVA followed by Least Significant Difference (LSD) Post-hoc test revealed significant difference among the groups ( p  < 0.05). It showed that SDI GIC group after 14 days of measurement had the highest mean of fluoride release (36.38 ± 3.16 PPM) and SDI RMGIC after 30 days of measurement had the second highest mean of fluoride release (43.28 ± 1.89 PPM). Finally, regarding the micromorphological analysis using SEM, a slight difference was observed between the studied groups. Conclusions Based on the results of this study, various coatings enhance surface roughness in the initial 24 h of restoration insertion. Different coat types seems that have no influence on fluoride release and the micromorphological features of the restoration/dentin interface.

Pt-based alloy catalysts may promise considerable mass activity (MA) for oxygen reduction but are generally unsustainable over long-term cycles, particularly in practical proton exchange membrane fuel cells (PEMFCs). Herein, we report a series of Pt-based intermetallic compounds (Pt₂Co, PtCo, and Pt₂Ti) enclosed by ultrathin Pt skin with an average particle size down to about 2.3 nm, which deliver outstanding cyclic MA and durability for oxygen reduction. By breaking size limitation during ordered atomic transformation in Pt alloy systems, the MA and durability of subsize Pt-based intermetallic compounds can be simultaneously optimized. The subsize scale was also found to enhance the stability of the membrane electrode through preventing the poisoning of catalysts by ionomers in humid fuel-cell conditions. We anticipate that subsize Pt-based intermetallic compounds set a good example for the rational design of high-performance oxygen reduction electrocatalysts for PEMFCs. Furthermore, the prevention of ionomer poisoning was identified as the critical parameter for assembling robust commercial membrane electrodes in PEMFCs.