Antimicrobial properties and dentin bonding strength of magnesium phosphate cements

An Injectable Magnesium-Based Cement Stimulated with NIR for Drug-Controlled Release and Osteogenic Potential

Magnesium phosphate bone cement (MPC) has gained widespread usage in orthopedic implantation due to its fast-setting and high initial strength benefits. However, the simultaneous attainment of drug-controlled release and osteogenic potential in MPC remains a significant challenge. Herein, a strategy to create a smart injectable cement system using nanocontainers and chondroitin sulfate is proposed. It employs nanocontainers containing alendronate-loaded mesoporous silica nanoparticles, which are surface-modified with polypyrrole to control drug release in response to near-infrared (NIR) stimulation. The alendronate-incorporated cement (ACMPC) exhibits improved compressive strength (70.6 ± 5.9 MPa), prolonged setting time (913 s), and exceptional injectability (96.5% of injection rate and 242 s of injection time). It also shows the capability to prevent degradation, thus preserving mechanical properties. Under NIR irradiation, the cement shows good antibacterial properties due to the combined impact of hyperthermia, reactive oxygen species, and alendronate. Furthermore, the ACMPC (NIR) group displays good biocompatibility and osteogenesis capabilities, which also lead to an increase in alkaline phosphatase activity, extracellular matrix mineralization, and the upregulation of osteogenic genes. This research has significant implications for developing multifunctional biomaterials and clinical applications.

Design and fabrication of high-performance injectable self-setting trimagnesium phosphate

Magnesium phosphate bone cement has become a widely used orthopedic implant due to the advantages of fast-setting and high early strength. However, developing magnesium phosphate cement possessing applicable injectability, high strength, and biocompatibility simultaneously remains a significant challenge. Herein, we propose a strategy to develop high-performance bone cement and establish a trimagnesium phosphate cement (TMPC) system. The TMPC exhibits high early strength, low curing temperature, neutral pH, and excellent injectability, overcoming the critical limitations of recently studied magnesium phosphate cement. By monitoring the hydration pH value and electroconductivity, we demonstrate that the magnesium-to-phosphate ratio could manipulate the components of hydration products and their transformation by adjusting the pH of the system, which will influence the hydration speed. Further, the ratio could regulate the hydration network and the properties of TMPC. Moreover, in vitro studies show that TMPC has outstanding biocompatibility and bone-filling capacity. The facile preparation properties and these advantages of TMPC render it a potential clinical alternative to polymethylmethacrylate and calcium phosphate bone cement. This study will contribute to the rational design of high-performance bone cement.

An Overview of Magnesium-Phosphate-Based Cements as Bone Repair Materials

In the search for effective biomaterials for bone repair, magnesium phosphate cements (MPCs) are nowadays gaining importance as bone void fillers thanks to their many attractive features that overcome some of the limitations of the well-investigated calcium-phosphate-based cements. The goal of this review was to highlight the main properties and applications of MPCs in the orthopedic field, focusing on the different types of formulations that have been described in the literature, their main features, and the in vivo and in vitro response towards them. The presented results will be useful to showcase the potential of MPCs in the orthopedic field and will suggest novel strategies to further boost their clinical application.

An injectable porous bioactive magnesium phosphate bone-cement foamed with calcium carbonate and citric acid for periodontal bone regeneration

Magnesium phosphate cement (MPC) has been evaluated as a novel bone substitute owing to its favorable biocompatibility, plasticity, and osteogenic potential. However, the low porosity of MPC prevents growth factors and osteoblasts from fully growing into the material, thereby limiting its clinical use. In this study, different concentrations (0-5%) of calcium carbonate and citric acid (CA) were used as foaming agents to prepare porous MPC. The MPC containing 3% CaCO₃/CA exhibited the best physicochemical properties, including greater porosity, improved injectability, extended setting time, and decreased hydration temperature. The proliferation and adhesion of cells on 3%CaCO₃/CA-MPC were higher than those on MPC alone. To explore its osteogenesis in vivo, 3% CaCO₃/CA-MPC and Bio-Oss® bone powder were implanted into periodontal bone defects in rats for 4 weeks and 12 weeks, respectively. Micro-CT and histological analysis demonstrated the improved bone regeneration of 3%CaCO₃/CA-MPC compared to the blank group (P < 0.05); it had slightly lower bone regeneration than the Bio-Oss® group but no statistical difference. The results indicated that porous MPC foamed with calcium carbonate and CA improved its physicochemical properties and enhanced its biocompatibility, making it a promising material for bone regeneration.

Bone adhesive materials: From bench to bedside

Biodegradable bone adhesives represent a highly sought-after type of biomaterial which would enable replacement of traditional metallic devices for fixation of bone. However, these biomaterials should fulfil an extremely large number of requirements. As a consequence, bone-adhesive biomaterials which meet all of these requirements are not yet commercially available. Therefore, this comprehensive review provides an extensive overview of the development of bone adhesives from a translational perspective. First, the definition, classification, and chemistry of various types of bone adhesives are highlighted to provide a detailed overview of this emerging class of biomaterials. In this review we particularly focused studies which describe the use of materials that are capable of gluing two pieces of bone together within a time frame of minutes to days. Second, this review critically reflects on i) the experimental conditions of commonly employed adhesion tests to assess bone adhesion and ii) the current state-of-the-art regarding their preclinical and clinical applicability.

Characterization and Biomechanical Study of a Novel Magnesium Potassium Phosphate Cement

Magnesium potassium phosphate cement (MKPC) has attracted considerable attention as a bone regeneration material. However, there are only a few reports on its biomechanical properties. To evaluate the biomechanical properties of MKPC, we compared the mechanical parameters of pedicle screws enhanced with either MKPC or polymethyl methacrylate (PMMA) bone cement. The results show that the maximum pull-out force of the pedicle screws was 417.86 ± 55.57 and 444.43 ± 19.89 N after MKPC cement setting for 30 min and 12 h, respectively, which was better than that of the PMMA cement. In fatigue tests, the maximum pull-out force of the MKPC cement group was 435.20 ± 7.96 N, whereas that of the PMMA cement in the control group was 346.80 ± 7.66 N. Furthermore, the structural characterization analysis of the MKPC cement revealed that its microstructure after solidification was an irregular tightly packed crystal, which improved the mechanical strength of the cement. The maximum exothermic temperature of the MKPC reaction was 45.55 ± 1.35 °C, the coagulation time was 7.89 ± 0.37 min, and the compressive strength was 48.29 ± 4.76 MPa, all of which meet the requirements of clinical application. In addition, the MKPC cement did not significantly inhibit cell proliferation or increase apoptosis, thus indicating good biocompatibility. In summary, MKPC exhibited good biomechanical properties, high initial strength, good biocompatibility, and low exothermic reaction temperature, demonstrating an excellent application potential in the field of orthopedics.

Characterization of Tetracalcium Phosphate/Monetite Biocement Modified by Magnesium Pyrophosphate

Magnesium pyrophosphate modified tetracalcium phosphate/monetite cement mixtures (MgTTCPM) were prepared by simple mechanical homogenization of compounds in a ball mill. The MgP₂O₇ was chosen due to the suitable setting properties of the final cements, in contrast to cements with the addition of amorphous (Ca, Mg) CO₃ or newberite, which significantly extended the setting time even in small amounts (corresponding ~to 1 wt% of Mg in final cements). The results showed the gradual dissolution of the same amount of Mg₂P₂O₇ phase, regardless of its content in the cement mixtures, and the refinement of formed HAP nanoparticles, which were joined into weakly and mutually bound spherical agglomerates. The compressive strength of composite cements was reduced to 14 MPa and the setting time was 5–10 min depending on the composition. Cytotoxicity of cements or their extracts was not detected and increased proliferative activity of mesenchymal stem cells with upregulation of osteopontin and osteonectin genes was verified in cells cultured for 7 and 15 days in cement extracts. The above facts, including insignificant changes in the pH of simulated body fluid solution and mechanical strength close to cancellous bone, indicate that MgTTCPM cement mixtures could be suitable biomaterials for use in the treatment of bone defects.

Formulation of inherently antimicrobial magnesium oxychloride cement and the effect of supplementation with silver phosphate

The growing threat of bacterial resistance to antibiotics is driving an increasing need for new antimicrobial strategies. This work demonstrates the potential of magnesium oxychloride cements (MOC) to be used as inorganic antimicrobial biomaterials for bone augmentation. An injectable formulation was identified at a powder to liquid ratio of 1.4 g mL^-1, with an initial setting time below 30 mins and compressive strength of 35 ± 9 MPa. Supplementation with Ag₃PO₄ to enhance the antimicrobial efficacy of MOC was explored, and shown via real time X-ray diffraction to retard the formation of hydrated oxychloride phases by up to 30%. The antimicrobial efficacy of MOC was demonstrated in vitro against Staphylococcus aureus and Pseudomonas aeruginosa, forming zones of inhibition and significantly reducing viability in broth culture. Enhanced efficacy was seen for silver doped formulations, with complete eradication of detectable viable colonies within 3 h, whilst retaining the cytocompatibility of MOC. Investigating the antimicrobial mode of action revealed that Mg and Ag release and elevated pH contributed to MOC efficacy. Sustained silver release was demonstrated over 14 days, suggesting the Ag₃PO₄ modified formulation offers two mechanisms of infection treatment, combining the inherent antimicrobial properties of MOC with controlled release of inorganic antimicrobials.

Bibliometric Analysis of Literature Published on Antibacterial Dental Adhesive from 1996-2020

This study aimed to investigate the current state of research on antibacterial dental adhesives. The interest in this field can be drawn from an increasing number of scholarly works in this area. However, there is still a lack of quantitative measurement of this topic. The main aim of this study was to consolidate the research published on the antibacterial adhesive from 1996 to 2020 in Web of Science indexed journals. The bibliometric method, a quantitative study of investigating publishing trends and patterns, was used for this study. The result has shown that a gradual increase in research was found, whereby a substantial increase was observed from 2013. A total of 248 documents were published in 84 journals with total citations of 5107. The highly cited articles were published mainly in Q1 category journals. Most of the published articles were from the USA, China, and other developed countries; however, some developing countries contributed as well. The authorship pattern showed an interdisciplinary and collaborative approach among researchers. The thematic evaluation of keywords along with a three-factor analysis showed that 'antibacterial adhesives' and 'quaternary ammonium' have been used commonly. This bibliometric analysis can provide direction not only to researchers but also to funding organizations and policymakers.

Cu-loaded Brushite bone cements with good antibacterial activity and operability

Bone defect-related surgical procedures are traumatic processes carrying potential inflammation and infection risks in the clinic, which are associated with prolonged antibiotic therapy that promotes bacterial antibiotic-resistance. In the present study, Cu-loaded brushite bone cements were designed, and the properties of the bone cements were evaluated. The setting time of the cement was prolonged from 12 to 50 min as the copper content increased. All cements were anti-washout, and the injectable coefficient of the cements was approximately 88%. Scanning electron microscopy results revealed that the crystal grains grew larger and thicker as the copper content in the cement increased, and brushite was determined to be the dominant crystalline phase for all the cements. However, a small amount of newly formed calcium copper phosphate was observed in the cement. Simultaneously, band shifts were observed in the Fourier transform infrared spectroscopy results at a Cu content of 5%. Moreover, the addition of Cu improved the compressive strength of brushite cements, and all cements were degradable. Furthermore, the Cu-loaded brushite bone cements performed well in inhibiting the growth and proliferation of Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa, and the diameter of the inhibition zone increased with increasing copper content. The study revealed that the Cu-loaded brushite bone cements possessed good cellular affinity to mouse bone marrow stem cells when a lower dose of copper was added in vitro. These results support the great potential of injectable antibacterial brushite bone cement specifically for bone tissue defect-related repair and regeneration.

Unravelling the Effect of Citrate on the Features and Biocompatibility of Magnesium Phosphate-Based Bone Cements

In the framework of new materials for orthopedic applications, Magnesium Phosphate-based Cements (MPCs) are currently the focus of active research in biomedicine, given their promising features; in this field, the loading of MPCs with active molecules to be released in the proximity of newly forming bone could represent an innovative approach to enhance the in vivo performances of the biomaterial. In this work, we describe the preparation and characterization of MPCs containing citrate, an ion naturally present in bone which presents beneficial effects when released in the proximity of newly forming bone tissue. The cements were characterized in terms of handling properties, setting time, mechanical properties, crystallinity, and microstructure, so as to unravel the effect of citrate concentration on the features of the material. Upon incubation in aqueous media, we demonstrated that citrate could be successfully released from the cements, while contributing to the alkalinization of the surroundings. The cytotoxicity of the materials toward human fibroblasts was also tested, revealing the importance of a fine modulation of released citrate to guarantee the biocompatibility of the material.

Insitu magnesium calcium phosphate cements formation: From one pot powders precursors synthesis to in vitro investigations

Calcium phosphate cements are of great interest for researchers and their applications in medical practice expanded. Nevertheless, they have a number of drawbacks including the insufficient level of mechanical properties and low degradation rate. Struvite (MgNH4PO4) -based cements, which grew in popularity in recent years, despite their neutral pH and acceptable mechanical performance, release undesirable NH4 + ions during their resorption. This issue could be avoided by replacement of ammonia ions in the cement liquid with sodium, however, such cements have a pH values of 9-10, leading to cytotoxicity. Thus, the main goal of this investigation is to optimize the composition of cements to achieve the combination of desirable properties: neutral pH, sufficient mechanical properties, and the absence of cytotoxicity, applying Na2HPO4-based cement liquid. For this purpose, cement powders precursors in the CaO-MgO-P2O5 system were synthesized by one-pot process in a wide composition range, and their properties were investigated. The optimal performance was observed for the cements with (Ca + Mg)/P ratio of 1.67, which are characterized by newberyite phase formation during setting reaction, pH values close to 7, sufficient compressive strength up to 22 ± 3 MPa (for 20 mol.% of Mg), dense microstructure and adequate matrix properties of the surface. This set of features make those materials promising candidates for medical applications.

3D plotting in the preparation of newberyite, struvite, and brushite porous scaffolds: using magnesium oxide as a starting material

Calcium phosphate (CaP)-containing materials, such as hydroxyapatite and brushite, are well studied bone grafting materials owing to their similar chemical compositions to the mineral phase of natural bone and kidney calculi. In recent studies, magnesium phosphate (MgP)-containing compounds, such as newberyite and struvite, have shown promise as alternatives to CaP. However, the different ways in degradation and release of Mg²⁺ and Ca²⁺ ions in vitro may affect the biocompatibility of CaP and MgP-containing compounds. In the present paper, newberyite, struvite, and brushite 3D porous structures were constructed by 3D-plotting combining with a two-step cementation process, using magnesium oxide (MgO) as a starting material. Briefly, 3D porous green bodies fabricated by 3D-plotting were soaked in (NH₄)₂HPO₄ solution to form semi-manufactured 3D porous structures. These structures were then soaked in different phosphate solutions to translate the structures into newberyite, struvite, and brushite porous scaffolds. Powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectrometry (EDS) were used to characterize the phases, morphologies, and compositions of the 3D porous scaffolds. The porosity, compressive strength, in vitro degradation and cytotoxicity on MC3T3-E1 osteoblast cells were assessed as well. The results showed that extracts obtained from immersing scaffolds in alpha-modified essential media induced minimal cytotoxicity and the cells could be attached merely onto newberyite and brushite scaffolds. Newberyite and brushite scaffolds produced through our 3D-plotting and two-step cementation process showed the sustained in vitro degradation and excellent biocompatibility, which could be used as scaffolds for the bone tissue engineering.

Novel injectable strontium-hardystonite phosphate cement for cancellous bone filling applications

Injectable bone cement (IBC) such as those based on methacrylates and hydraulic calcium phosphate and calcium sulfate-based cements have been used extensively for filling bone defects with acceptable clinical outcomes. There is a need however for novel IBC materials that can address some of the inherent limitations of currently available formulations to widen the clinical application of IBC. In this study, we characterized a novel hydraulic IBC formulation consisting of bioactive strontium-doped hardystonite (Sr-HT) ceramic microparticles and sodium dihydrogen phosphate, herein named Sr-HT phosphate cement (SPC). The resultant cement is comprised of two distinct amorphous phases with embedded partially reacted crystalline reactants. The novel SPC formulation possesses a unique combination of physicochemical properties suitable for use as an IBC, and demonstrates in vitro cytocompatibility when seeded with primary human osteoblasts. In vivo injection of SPC into rabbit sinus defects show minor new bone formation at the SPC periphery, similar to those exhibited in sinus defects filled with a clinically available calcium phosphate cement. The current SPC formulation presented in this paper shows promise as a clinically applicable IBC which can be further enhanced with additives.

In vivo efficiency of antimicrobial inorganic bone grafts in osteomyelitis treatments

The purpose of the present work was to evaluate in vivo different antimicrobial therapies to eradicate osteomyelitis created in the femoral head of New Zealand rabbits. Five phosphate-based cements were evaluated: calcium phosphate cements (CPC) and calcium phosphate foams (CPF), both in their pristine form and loaded with doxycycline hyclate, and an intrinsic antimicrobial magnesium phosphate cement (MPC; not loaded with an antibiotic). The cements were implanted in a bone previously infected with Staphylococcus aureus to discern the effects of the type of antibiotic administration (systemic vs. local), porosity (microporosity, i.e. <5 μm vs. macroporosity, i.e. >5 μm) and type of antimicrobial mechanism (release of antibiotic vs. intrinsic antimicrobial activity) on the improvement of the health state of the infected animals. A new method was developed, with a more comprehensive composite score that integrates 5 parameters of bone infection, 4 parameters of bone structural integrity and 4 parameters of bone regeneration. This method was used to evaluate the health state of the infected animals, both before and after osteomyelitis treatment. The results showed that the composite score allows to discern statistically significant differences between treatments that individual evaluations were not able to identify. Despite none of the therapies completely eradicated the infection, it was observed that macroporous materials (CPF and CPFd, the latter loaded with doxycycline hyclate) and intrinsic antimicrobial MPC allowed a better containment of the osteomyelitis. This study provides novel insights to understand the effect of different antimicrobial therapies in vivo, and a promising comprehensive methodology to evaluate the health state of the animals was developed. We expect that the implementation of such methodology could improve the criteria to select a proper antimicrobial therapy.

Identification of Magnesium Oxychloride Cement Biomaterial Heterogeneity using Raman Chemical Mapping and NIR Hyperspectral Chemical Imaging

The present study investigated spatial heterogeneity in magnesium oxychloride cements within a model of a mould using hyperspectral chemical imaging (HCI). The ability to inspect cements within a mould allows for the assessment of material formation in real time in addition to factors affecting ultimate material formation. Both macro scale NIR HCI and micro scale pixel-wise Raman chemical mapping were employed to characterise the same specimens. NIR imaging is rapid, however spectra are often convoluted through the overlapping of overtone peaks, which can make interpretation difficult. Raman spectra are more easily interpretable, however Raman imaging can suffer from slower acquisition times, particularly when the signal to noise ratio is relatively poor and the spatial resolution is high. To overcome the limitations of both, Raman/NIR data fusion techniques were explored and implemented. Spectra collected using both modalities were co-registered and intra and inter-modality peak correlations were investigated while k-means cluster patterns were compared. In addition, partial least squares regression models, built using NIR spectra, predicted chemical-identifying Raman peaks with an R2 of up to >0.98. As macro scale imaging presented greater data collection speeds, chemical prediction maps were built using NIR HCIs.

Magnesium-based bioceramics in orthopedic applications

Magnesium ions are directly involved in numerous biological mechanisms; for example, they play an important part in the regulation of ion channels, DNA stabilization, enzyme activation and stimulation of cell growth and proliferation. This alkaline earth metal has gained great popularity in orthopedic applications in recent years. Magnesium-based bioceramics include a large group of magnesium containing compounds such as oxides, phosphates and silicates, that are involved in orthopedic applications like bone cements, bone scaffolds or implant coatings. This article aims to give a comprehensive review on different magnesium-based bioceramics, e.g. magnesium phosphates (MgO-P₂O₅), calcium magnesium phosphates (CaO-MgO-P₂O₅), and magnesium glasses (SiO₂-MgO) with a strong focus on the chemistry and properties of magnesium phosphate containing cements as the main application form. In addition, the processing of magnesium phosphate minerals into macroporous scaffolds for tissue engineering applications by either using traditional porogens or by additive manufacturing approaches are reflected. Finally, the biological in vitro and in vivo properties of magnesium phosphates for bone regeneration are summarized, which show promising results regarding the application as bone replacement material, but still lack in terms of testing in large animal models, load-bearing application sites and clinical data.

STATEMENT OF SIGNIFICANCE

Though bone substitutes from calcium phosphates have been investigated for a long time, a new trend is visible in the biomaterials sector: magnesium based bioceramics from magnesium phosphates and silicates due to the special biological significance of magnesium ions in enzymatic activation, cell growth and proliferation, etc. In contrast to pure magnesium implants, such formulations do not release hydrogen during degradation. As with calcium based bioceramics, magnesium based bioceramics are used for the development of diverse applications such as cements, macroporous scaffolds and coatings. From this perspective, we present a systematic overview on diverse kinds of magnesium based bioceramics, their processing regimes for different clinical purposes and their behavior both in vitro and in vivo.

Magnesium Phosphate Cement Systems for Hard Tissue Applications: A Review

In the search for more ideal bone graft materials for clinical application, the investigation into ceramic bone cements or bone void filler is ongoing. Calcium phosphate-based materials have been widely explored and implemented for medical use in bone defect repair. Such materials are an excellent choice because the implant mimics the natural chemistry of mineralized bone matrix and in injectable cement form, can be implemented with relative ease. However, of the available calcium phosphate cements, none fully meet the ideal standard, displaying low strengths and acidic setting reactions or slow setting times, and are often very slow to resorb in vivo. The study of magnesium phosphates for bone cements is a relatively new field compared to traditional calcium phosphate bone cements. Although reports are more limited, preliminary studies have shown that magnesium phosphate cements (MPC) may be a strong alternative to calcium phosphates for certain applications. The goal of the present publication is to review the history and achievements of magnesium phosphate-based cements or bone void fillers to date, assess how these cements compare with calcium phosphate competitors and to analyze the future directions and outlook for the research, development, and clinical implementation of these cements.

Assessments of antibacterial and physico-mechanical properties for dental materials with chemically anchored quaternary ammonium moieties: thiol-ene-methacrylate vs. conventional methacrylate system

OBJECTIVE

Fabrication of low shrinkage stress and strain dental resins containing highly available immobilized bactericidal moieties has been reported. The goal of this study is producing dental restorative materials with long-last antibacterial activity and reduced secondary caries. It is anticipated that antibacterial properties of quaternary ammonium moieties chemically immobilized in the backbone of dental resins is directly depended on accessibility of these functions. In the present study the antibacterial effect of a series of antibacterial monomers polymerized in a ternary thiol-ene-methacrylate system were compared with corresponding classical methacrylate system against Streptococcus mutans (an oral bacteria Strain). Physical and mechanical properties of dental materials obtained from these two systems were also evaluated and compared.

METHODS

The viscosities of the resin matrixes were measured on a MCR 300 rheometer. Degree of conversion (DC%) of monomers was measured using FTIR spectroscopy. The shrinkage-strain of photocured resins was measured using the bonded-disk technique. A universal testing machine combined with a stress measurement device was utilized to measure the polymerization-induced shrinkage stress. Viscoelastic properties of the samples were also determined by dynamic mechanical thermal analysis (DMTA). Assessment of antibacterial properties was performed through agar diffusion test (AD) to confirm non-release behavior of chemically anchored moieties. Quantitative assay of antibacterial activity was evaluated through direct contact test (DCT) against S. mutans. Direct contact cytotoxicity assay with fibroblast cell line L-929 was also performed to find more insight regarding cytotoxicity of the antibacterial matrixes. The data were analyzed and compared by ANOVA and Tukey HSD tests (significance level=0.05).

RESULTS

Neat methacrylate systems had significantly higher viscosity than thiol-ene-methacrylate analogous. The degree of conversion of methacrylate moieties in thiol-ene-methacrylate system was improved in comparison to conventional methacrylate system. Shrinkage stress and strain of thiol-ene-methacrylate system was lower than the neat methacrylate system. The thiol-ene-methacrylate systems show increased homogeneity and decreased glass transition temperature (Tg) and crosslink density (νc) in comparison to the neat methacrylate-based resins. The incorporated monofuctional quaternized monomer reduces degree of conversion, shrinkage stress and crosslink density of matrix. The results showed significant improvement in antibacterial activity and cytocompatibility of dental materials obtained from thiol-ene polymerization system.

SIGNIFICANCE

It was shown that with proper control of monomers molar ratio, significant improvement in antibacterial activity and cytocompatibility as well as acceptable mechanical properties can be attained for dental resins prepared through the application of thiol-ene polymerization methodology.