Open Access

Abstract The incorporation of bioactive agents into resin-modified glass ionomer cement (RMGIC) is a promising strategy to improve its mechanical strength and biofilm control, especially for patients with active dental caries. Objective This study aimed to evaluate the effects of incorporating ZnONPs and CaGP into RMGIC on its mechanical and microbiological properties. Design Six groups were tested: 1) RMGIC (without CaGP/ZnONPs); 2) RMGIC-1.0%ZnONPs; 3) RMGIC-2.0%ZnONPs; 4) RMGIC-3.0%CaGP; 5) RMGIC-3.0%CaGP-1.0%ZnONPs; and 6) RMGIC-3.0%CaGP-2.0%ZnONPs. The compressive strength (CS), diametral tensile strength (DTS), and surface hardness (SH) were evaluated after 24 hours and 7 days. Antimicrobial and antibiofilm activity were evaluated using agar diffusion and biofilm metabolic activity (XTT) assays. Results After 24 hours, all the groups showed similar DTS values (p0.05), except for RMGIC-3.0%CaGP-1.0%ZnONPs, which showed the highest DTS value (p<0.05). Comparing 24 hours and 7 days, the DTS values of RMGIC-3.0%CaGP-2.0%ZnONPs, RMGIC-3.0%CaGP, and RMGIC-3.0%CaGP-2.0%ZnONPs were similar (p=0.360). After 24 hours, the RMGIC group showed the CS highest value, followed by RMGIC-2.0%ZnONPs (p < 0.05). After 7 days, the RMGIC-3.0%CaGP-1.0%ZnONPs group exhibited the highest CS value, approximately 15% higher than RMGIC (p<0.05). The RMGIC-1.0%ZnONPs group exhibited significantly higher SH at 24 hours (p=0.621). At 7 days, the highest SH value was observed for the RMGIC-3.0%CaGP-1.0%ZnONPs group (p<0.05). Regarding antimicrobial and antibiofilm activity, including results from biofilm metabolism assays, the RMGIC-3.0%CaGP-1.0%ZnONPs group demonstrated the most effective antimicrobial and inhibitory effects (p<0.05). Conclusion This study demonstrated that adding ZnONPs and CaGP to RMGIC enhanced its mechanical and antimicrobial and antibiofilm properties, suggesting enhanced mechanical performance and improved protection against cariogenic biofilms—critical factors for successful restorative treatments. Therefore, the addition of ZnONPs and CaGP is a promising strategy to develop advanced restorative materials that improve clinical outcomes, especially for patients with active dental caries.

Chemically complex materials (CCMats) 􀀀 including high-entropy alloys, oxides, and related multi-principal element systems 􀀀 offer a paradigm shift in materials design by leveraging chemical diversity to simultaneously optimize functional, structural, and sustainability criteria. The vastness of the compositional and structural space in CCMats propels the field into an expanding exploratory state. To reconcile functional and structural performance across this immense parameter space remains an open challenge. This Perspective evaluates the opportunities and challenges associated with harnessing chemical complexity across a broad spectrum of applications, such as hydrogen storage, ionic conductors, catalysis, magnetics, dielectrics, semiconductors, optical materials, and multifunctional structural systems. It is delineated how three central design strategies: targeted substitution (SUB), defect engineering (DEF), and diversity management (DIV) enable the reconciliation of high functional performance with long-term structural stability and environmental responsibility. Advances in computational thermodynamics, microstructure simulations, machine learning, and multimodal characterization are accelerating the exploration and optimization of CCMats, while robust data infrastructures and automated synthesis workflows are emerging as essential tools for navigating their complex compositional space. By fostering cross-disciplinary knowledge transfer and embracing data-driven design, CCMats are poised to deliver next-generation materials solutions that address urgent technological, energy, and environmental demands.

As the development of optimized glass compositions by traditional trial-and-error methods is laborious, expensive, and time consuming, it is desirable to gather fundamental understanding of structure and to develop structure-property relation models, which allow best and faster choices. Particularly, when it comes to optical applications of glasses doped with emissive trivalent rare earth ions (RE), the chemical environmental around the ions will have a direct influence on the radiative/non-radiative emission probabilities. The vibrational environment and the chemical nature of the bonds in the first coordination sphere of the ions can be tailored, to some extent, based on structural information given by magnetic resonance (NMR and EPR) techniques associated to Raman and photophysical characterization. For the past 5 years, one of the interests of my research group at the University of São Paulo, in Brazil, has been the development of high-density fluoride-phosphate glasses as promising UV and X-ray scintillator materials. The targeted glasses offer a lower vibrational energy, less hygroscopic fluoride environment for the RE ions whereas the phosphate network provides improved mechanical and chemical stability than a purely fluoride glass matrix. Different sets of glasses, based on the compositional system (Ba/Sr)F2-M(PO3)3-MF3-(Sc/Y)F3 where M = Al, In, Ga, and the phosphate component is substituted by the fluoride analogue in 10-30 mol%, were investigated, using Sc3+, Y3+, and the Eu3+ and Yb3+ dopants, as structural probes. Overall, results show that the desired RE coordination by F, at a given F/P ratio, is proportional to the atomic mass of M (In> Ga> Al) and that the Ga- and In- based systems differ from the Al- one by near absence of P-O-P network linkages i.e, the network structures are dominated by Ga-O-P or In-O-P linkages as evidenced by 31P MAS-NMR and Raman. These results are nicely corroborated by observation of decreased intensity in the vibronic band of Eu3+ and significant increase in the excited state lifetime values. Radioluminescence studies were carried out for a series of In-based glasses doped with Ce3+ and Tb3+ yielding intense emissions in the blue and green, respectively, compatible to the spectral region of highest sensitivity of radiation sensor detectors. The aim of the presentation is to show how powerful the combination of NMR, EPR, Raman and PLE spectroscopies can be to provide structural information and to present the perspectives for their introduction in the research agenda of Division 5.6 – Glass, which I now lead, at the Federal Institute for Materials Research and Testing (BAM) in Berlin, Germany.

As the development of optimized glass compositions by traditional trial-and-error methods is laborious, time consuming, and expensive, it is desirable to develop glass compositions based on a fundamental understanding of the glass structure and to establish structure-property relation models. Particularly, when it comes to optical applications of glasses doped with emissive trivalent rare earth ions (RE), the chemical environmental around the ions will have a direct influence on the radiative/non-radiative emission probabilities. The local vibrational environment and the chemical nature of the bonds in the first coordination sphere of the ions can be tailored, to good extent, based on structural information given by magnetic resonance techniques (NMR and EPR), associated to Raman and photophysical characterization. For the past 5 years, while still employed at the University of São Paulo, in Brazil, one of the interests of my research group has been the development of high-density fluoride-phosphate glasses as promising UV and X-ray scintillator materials. The targeted glasses offer a lower vibrational energy, less hygroscopic fluoride environment for the RE ions whereas the phosphate network provides better mechanical and chemical stability than a purely fluoride glass matrix. Different sets of glasses, based on the compositional system (Ba/Sr)F2-M(PO3)3-MF3-(Sc/Y)F3 where M = Al, In, Ga, and the phosphate component is substituted by the fluoride analogue in 10 - 30 mol%, were investigated, using Sc3+, Y3+, and the Eu3+ and Yb3+ dopants, as structural probes. Overall, results show that the desired RE coordination by fluorine, at a given F/P ratio, is proportional to the atomic mass of M (In> Ga> Al) and that the Ga- and In- based systems differ from the Al- one by near absence of P-O-P network linkages. That is, the network structures are dominated by Ga-O-P or In-O-P linkages, as evidenced by 31P MAS-NMR and Raman. These results are nicely corroborated by observation of decreased intensity of the vibronic band in Eu3+-doped glasses and marked increase in excited state lifetime values. Radioluminescence studies were carried out for a series of In-based glasses doped with Ce3+ and Tb3+, yielding intense emissions in the blue and green, respectively, compatible to the spectral region of the highest sensitivity of radiation sensor detectors. The aim of the presentation is to show how powerful the NMR and EPR techniques can be to provide decisive structural information, and to present the research perspectives in my new role as the Head of Division 5.6 – Glass at BAM.

An overview of the Glass Digitalization efforts at BAM, within the framework of the Glass Digital consortium, was given. From the development of the robotic melting device to the ML capabilities, a description of the different stages of the developments and roles of project partner was presented.