Evaluation of the Flexural Strength, Water Sorption, and Solubility of a Glass Ionomer Dental Cement Modified Using Phytomedicine

Scribante A., Vallittu P., Lassila L.V., Viola A., Tessera P., Gandini P., Sfondrini M.F.

Fiber-reinforced composite (FRC) retainers are an aesthetic alternative to conventional Stainless Steel splints. They are generally used with a full bonded technique, but some studies demonstrated that they could be managed with a spot bonding technique to significantly decrease their rigidity. In order to propose this FRC spot bonding technique for clinical use, the aim of this study was to evaluate mechanical properties and surface wear of fibers left uncovered. Tests were made by simulating tooth brushing, comparing FRC spot bonding technique splints with stainless steel and FRC traditional technique splints. Specimens were tested both at 0.1 mm of deflection and at maximum load, showing higher values of rigidity for the FRC full bonded technique. After tooth brushing, no significant reduction in values at 0.1 mm deflection was reported, while we found a similar reduction in these values for the Stainless Steel and FRC spot bonding technique at maximum load, and no significant variation for the FRC full bonded technique. SEM images after tooth brushing showed wear for FRC fibers left uncovered, while no relevant wear signs in metal and conventional FRC fibers were noticed. Results showed that FRC spot bonding technique has advantages in mechanical properties when compared to the FRC traditional full bonding technique, also after tooth brushing. However, the surface wear after tooth brushing in the FRC spot bonding technique is considerable and other tests must be performed before promoting this technique for routine clinical use.

Ausiello P., Ciaramella S., Di Rienzo A., Lanzotti A., Ventre M., Watts D.C.

To investigate the influence of different resin composite and glass ionomer cement material combinations in a "bi-layer" versus a "single-layer" adhesive technique for class I cavity restorations in molars using numerical finite element analysis (FEA).Three virtual restored lower molar models with class I cavities 4mm deep were created from a sound molar CAD model. A combination of an adhesive and flowable composite with bulk fill composite (model A), of a glass ionomer cement with bulk fill composite (model B) and of an adhesive with bulk fill composite (model C), were considered. Starting from CAD models, 3D-finite element (FE) models were created and analyzed. Solid food was modeled on the occlusal surface and slide-type contact elements were used between tooth surface and food. Polymerization shrinkage was simulated for the composite materials. Physiological masticatory loads were applied to these systems combined with shrinkage. Static linear analyses were carried out. The maximum normal stress criterion was adopted as a measure of potential damage.All models exhibited high stresses principally located along the tooth tissues-restoration interfaces. All models showed a similar stress trend along enamel-restoration interface, where stresses up to 22MPa and 19MPa was recorded in the enamel and restoration, respectively. A and C models showed a similar stress trend along the dentin-restoration interface with a lower stress level in model A, where stresses up to 11.5MPa and 7.5MPa were recorded in the dentin and restoration, respectively, whereas stresses of 17MPa and 9MPa were detected for model C. In contrast to A and C models, the model B showed a reduced stress level in dentin, in the lower restoration layer and no stress on the cavity floor.FE analysis supported the positive effect of a "bi-layer" restorative technique in a 4mm deep class I cavities in lower molars versus "single-layer" bulk fill composite technique.

Sajjad A., Zaripah Wan Bakar W., Mohamad D., Ponnuraj Kannan T.

In restorative dentistry, there has been a growing shift towards using nanoparticles dispersed in the polymer matrix to improve properties of dental restorative materials. A new nano zirconia–silica–hydroxyapatite (nanoZrO2–SiO2–HA) was synthesized by one-pot synthesis and characterized using transmission electron microscopy (TEM), scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray (EDX) and dot mapping. The effect of addition of nanoZrO2–SiO2–HA to the conventional GIC (cGIC) on the compressive strength, flexural strength and surface roughness was also evaluated. The characterization studies confirmed that all particles were in the nanoscale range with spherical zirconia and silica particles embedded in the voids between rod-shaped HA crystallites. The nano particles were evenly and homogenously dispersed throughout the sample with high density patterns visible for zirconia, calcium and phosphorus. The incorporation of 5% nanoZrO2–SiO2–HA has resulted in considerable improvement in the compressive and flexural strengths of cGIC. The GIC 5% nanoZrO2–SiO2–HA exhibited an increase in compressive (144.12 ± 13.88 MPa) and flexural strength (18.12 ± 2.33 MPa) over cGIC which was statistically significant (p ≤ 0.05). It also demonstrated surface roughness profile (0.15 ± 0.029 μm) similar to that of cGIC (0.15 ± 0.019 μm). Therefore, the nanoZrO2–SiO2– HA can be a promising filler for GIC to be used as restorative dental material in high stress bearing areas

Zarone F., Di Mauro M.I., Ausiello P., Ruggiero G., Sorrentino R.

The introduction of the new generation of particle-filled and high strength ceramics, hybrid composites and technopolymers in the last decade has offered an extensive palette of dental materials broadening the clinical indications in fixed prosthodontics, in the light of minimally invasive dentistry dictates. Moreover, last years have seen a dramatic increase in the patients’ demand for non-metallic materials, sometimes induced by metal-phobia or alleged allergies. Therefore, the attention of scientific research has been progressively focusing on such materials, particularly on lithium disilicate and zirconia, in order to shed light on properties, indications and limitations of the new protagonists of the prosthetic scene. This article is aimed at providing a narrative review regarding the state-of-the-art in the field of these popular ceramic materials, as to their physical-chemical, mechanical and optical properties, as well as to the proper dental applications, by means of scientific literature analysis and with reference to the authors’ clinical experience. A huge amount of data, sometimes conflicting, is available today. Both in vitro and in vivo studies pointed out the outstanding peculiarities of lithium disilicate and zirconia: unparalleled optical and esthetic properties, together with high biocompatibility, high mechanical resistance, reduced thickness and favorable wear behavior have been increasingly orientating the clinicians’ choice toward such ceramics. The noticeable properties and versatility make lithium disilicate and zirconia materials of choice for modern prosthetic dentistry, requiring high esthetic and mechanical performances combined with a minimal invasive approach, so that the utilization of such metal-free ceramics has become more and more widespread over time.

Kucukyilmaz E., Savas S., Colgecen O., Yasa B.

KUTUK Z.B., VURAL U.K., CAKIR F.Y., MILETIC I., GURGAN S.

Tüzüner T., Dimkov A., Nicholson J.W.

Aim: The aim of this article is to review the literature on the use of antimicrobial additives in glass-ionomer dental cements. Method: An electronic search between 1987 and the end of 2017 was performed using PubMed, Web of Science and Google search engines with the terms glass-ionomer, glass polyalkenoate, antibacterial and antimicrobial as the key words. The search was refined by excluding the majority of references concerned with cement antimicrobial properties only. Extra papers already known to the authors were added to those considered. Results: A total of 92 relevant articles have been cited in the review of which 55 are specifically concerned with the enhancement of antibacterial properties of glass-ionomers, both conventional and resin-modified, with additives. In addition, information is included on the uses of glass-ionomers and the biological properties of the antibacterial additives employed. There are several reports that show that additives are typically released by diffusion, and that a high proportion is usually left behind, trapped in the cement. Additives generally increase setting times of cements, and reduce mechanical properties. However, smaller amounts of additive have only slight effects and the longer-term durability of cements appears unaffected. Conclusion: Modified glass-ionomer cements seem to be acceptable for clinical use, especially in the Atraumatic Restorative Treatment (ART) technique.

Hwang S., Chung S., Lee J., Kim Y., Kim Y., Oh S., Yeo I.

This study investigated the influences of acidity, ethanol, and pigment on the optical properties, microhardness, and surface roughness (Ra) of a nanohybrid dental composite resin. A total of 108 disc-shaped specimens were fabricated using a nanohybrid dental composite and allocated into 36 different storage solutions according to the levels of pH (2.0, 3.0, 4.0, and 5.5), ethanol (0%, 20%, and 40%), and anthocyanin pigment (0%, 2.5%, and 12.5%). Measurements of the colorimetric parameter and the amount of color change (ΔE), translucency parameter (TP), microhardness, and surface roughness (Ra) were performed at 24 h (baseline), 1-, 2-, 3-, and 4-weeks. Repeated measures of analysis of variance (ANOVA) with a Tukey honestly significant difference test and Pearson correlation analysis were carried out (α = 0.05). Pigment of 12.5% or 40% ethanol significantly increased the ΔE (P < 0.001, P = 0.048, respectively). Pigment of 2.5% or 12.5% significantly decreased the TP (P = 0.001, P < 0.001, respectively). Microhardness of composite resin stored in pH 2.0, 3.0, 4.0 solution was lower than that for pH 5.5 (P < 0.001). Pigment, ethanol, and pH did not influence the Ra. TP change and ΔE, and Ra and ΔE had a significant positive correlation (P < 0.05). In conclusion, pigment and ethanol levels influenced the optical properties and acidity affected the microhardness of composite resin.

Garoushi S.K., He J., Vallittu P.K., Lassila L.V.

This study investigated the reinforcing effect of discontinuous glass microfibers with various loading fractions on selected mechanical properties of self-cure glass ionomer cement (GIC).Experimental fiber reinforced GIC (Exp-GIC) was prepared by adding discontinuous glass microfiber (silane/non-silane treated) of 200-300 µm in length to the powder of self-cure GIC (GC Fuji IX) with various mass ratios (15, 20, 25, 35, and 45 mass%) using a high speed mixing device. Flexural strength, flexural modulus, work of fracture, compressive strength and diametral tensile strength were determined for each experimental and control materials. The specimens (n = 8) were wet stored (37 °C for one day) before testing. Scanning electron microscopy equipped with energy dispersive spectrometer was used to analysis the surface of silanized or non-silanized fibers after treated with cement liquid. The results were analyzed with using multivariate analysis of variance MANOVA.Fiber-reinforced GIC (25 mass%) had significantly higher mechanical performance of flexural modulus (3.8 GPa), flexural strength (48 MPa), and diametral tensile strength (18 MPa) (p < .05) compared to unreinforced material (0.9 GPa, 26 MPa and 8 MPa). No statistical significant difference in tested mechanical properties was recorded between silanized and non-silanized Exp-GIC groups. Compressive strength did not show any significant differences (p > .05) between the fiber-reinforced and unreinforced GIC.The use of discontinuous glass microfibers with self-cure GIC matrix considerably increased the all of the studied properties except compressive strength.

Ausiello P., Ciaramella S., Martorelli M., Lanzotti A., Gloria A., Watts D.C.

To investigate the influence of specific resin-composite, glass ceramic and glass ionomer cement (GIC) material combinations in a "multi-layer" technique to replace enamel and dentin in class II mesio-occlusal-distal (MOD) dental restorations using 3D-Finite Element Analysis (FEA).Four 3D-FE models (A-D) of teeth, adhesively restored with different filling materials, were created and analyzed in comparison with a 3D model (E) of a sound lower molar. Models A, B & C had "multilayer" constructions, consisting of three layers: adhesive, dentin replacement and enamel replacement. Model A: had a low modulus (8GPa) composite replacing dentin and a higher modulus (12GPa) composite replacing enamel. Model B: had a GI cement replacing dentin and a higher modulus (12GPa) composite replacing enamel. Model C: had a low modulus (8GPa) composite replacing dentin and a very high modulus (70GPa) inlay replacing enamel. Model D: had a lithium disilicate inlay replacing both dentin and enamel with a luting cement base-layer. Polymerization shrinkage effects were simulated and a load of 600N was applied. All the materials were assumed to behave elastically throughout the entire deformation.Model A showed the highest stress distribution along all the adhesive interfaces of the shrinking resin-based materials with a critical condition and failure risk marginally and internally. Model D, by contrast, showed a more favorable performance than either of the multilayer groups (A-C). Stress and displacement plots showed an elastic response similar to that obtained for the sound tooth model. Model B and Model C performed according to their bilayer material properties. The use of a non-shrink dentin component simulating a GIC clearly affected the shrinkage stress at the basis of the Model B; while the bulk resin composite having a 12GPa Young's modulus and linear polymerization shrinkage of 1% strongly influenced the biomechanical response in the bucco-lingual direction.Direct resin-based composite materials applied in multilayer techniques to large class II cavities, with or without shrinking dentin layers, produced adverse FEA stress distributions and displacements. An indirect lithium disilicate inlay used to replace lost dentin and enamel in posterior restored teeth generated lower stress levels, within the limits of the elastic FEA model.

Subramani R., Narayanasamy M., Feussner K.

Antibiotic resistance is becoming a pivotal concern for public health that has accelerated the search for new antimicrobial molecules from nature. Numbers of human pathogens have inevitably evolved to become resistant to various currently available drugs causing considerable mortality and morbidity worldwide. It is apparent that novel antibiotics are urgently warranted to combat these life-threatening pathogens. In recent years, there have been an increasing number of studies to discover new bioactive compounds from plant origin with the hope to control antibiotic-resistant bacteria. This review attempts to focus and record the plant-derived compounds and plant extracts against multi-drug-resistant (MDR) pathogens including methicillin-resistant Staphylococcus aureus (MRSA), MDR-Mycobacterium tuberculosis and malarial parasites Plasmodium spp. reported between 2005 and 2015. During this period, a total of 110 purified compounds and 60 plant extracts were obtained from 112 different plants. The plants reviewed in this study belong to 70 different families reported from 36 countries around the world. The present review also discusses the drug resistance in bacteria and emphasizes the urge for new drugs.

Okafor A.C., Igwesi S.N., David E.E., Okolo V.K., Agu K.

Sidhu S., Nicholson J.

De los Santos B.P., Kanis L.A., Pereira J.R.

The aim of this study was to do a literature review on herbal medicines used in dentistry. For that purpose, an electronic search of papers in Portuguese, Spanish, and English was performed in the following databases: PubMed, MEDLINE, SciELO, Science Direct, LILACS, and BBO, supplemented by hand search in books, theses, and journals. For the search, the following keywords were used: phytotherapy, Copaifera, and Baccharis dracunculifolia. Medicinal plants have been used since ancient times and some of them such as the Copaifera multijuga Hayne and Baccharis dracunculifolia DC have shown medicinal properties. Different ways to obtain extracts from those plants have been described, as well as their many important properties, such as antimicrobial, anti-inflammatory, and antiseptic effects. However, studies on their medicinal properties are still scarce, which indicates the need for further studies to unravel their effects and possible side effects, as well as implications of improper use of these plants.

Somani R., Jaidka S., Singh D., Shafat S.

Mathew J., Vishnudas S.

Thbayh K.K., AlBadr R.M., Ziadan K.M., Thbayh D.K., Mohi S.M., Fiser B.

Glass ionomer cement (GIC) is one of the most widely used restorative materials for temporary fillings and reconstructions in dentistry, but it has relatively poor mechanical properties that make its use limited, especially in places subject to high pressure. Thus, to extend the applicability of GIC, samples based on SiO2, P2O5, Al2O3, CaF2, and NaF were prepared with the addition of calcium oxide CaO extracted from natural sources (oyster shells) in different ratios of 0, 5, 10, 15, 20, and 25% wt. The suggested glass samples were evaluated, and their physical and mechanical properties were compared. XRD, SEM, and FTIR were performed on the samples. 24 specimens were prepared for each test in order to assess the mechanical properties as per the specific requirements. The tests included measuring bending strength, elastic modulus, adjusted direct tensile strength, absorption, water solubility, and diffusion coefficients after the specimens were stored in distilled water for 60 days. All calculations were carried out in accordance with standard procedures. The findings indicated a slight improvement in the bending resistance of the recommended GIC. Glass modified with 20% by weight of calcium oxide was the best among the ratios in terms of the results obtained and compared to the traditional commercial type. The malleable strength of the sample was 54.121 MPa, while the flexural modulus increased, the tensile strength reached 10.154 MPa, and the solubility was 25.87 µg/mm3 after storage for 60 days. These indicate that the developed material is suitable for use as a dental restoration material when compared to international commercial cement specifications.

Rini A., Juwita F., Bagjana R., Octivany S., Purnama R., Rijal M., Anwar A., Purwasasmita B., Asri L. .

ABSTRACTThis study aimed to evaluate the effect of incorporating nanocrystalline cellulose (NCC) sourced from rice husk on the mechanical properties of a commercial glass ionomer cement (GIC). NCC was isolated through acid hydrolysis, and its crystallinity, chemical structure, and morphology were characterized through x‐ray diffractometry, Fourier‐transform infrared spectroscopy, and transmission electron microscopy, respectively. Various concentrations of NCC (0%, 0.5%, 1%, and 1.5%) were added to reinforce the GIC matrix. Mechanical tests including compressive strength, flexural strength, hardness, and shear bond strength were conducted on the modified GIC samples. The addition of NCC resulted in increased hardness and shear bond strength values, with 1% NCC showing the highest values compared to other concentrations. However, there was no significant improvement observed in the compressive and flexural strength of the modified GIC. Failure mode test revealed a reduction in adhesive failure with the addition of NCC. Incorporating small amounts of NCC (0.5%–1%) suggests a promising and affordable modification of GIC restorative material using biomass residue, resulting in improved mechanical properties.

Leenutaphong N., Phantumvanit P., Young A.M., Panpisut P.

Abstract Background Low mechanical properties are the main limitation of glass ionomer cements (GICs). The incorporation of elastomeric micelles is expected to enhance the strength of GICs without detrimentally affecting their physical properties and biocompatibility. This study compared the chemical and mechanical properties, as well as the cytotoxicity, of elastomeric micelles-containing glass ionomer cement (DeltaFil, DT) with commonly used materials, including EQUIA Forte Fil (EF), Fuji IX GP Extra (F9), and Ketac Molar (KT). Method Powder particles of GICs were examined with SEM-EDX. Setting kinetics were assessed using ATR-FTIR. Biaxial flexural strength/modulus and Vickers surface microhardness were measured after immersion in water for 24 h and 4 weeks. The release of F, Al, Sr, and P in water over 8 weeks was analyzed using a fluoride-specific electrode and ICP-OES. The toxicity of the material extract on mouse fibroblasts was also evaluated. Results High fluoride levels in the powder were detected with EF and F9. DT demonstrated an initial delay followed by a faster acid reaction compared to other cements, suggesting an improved snap set. DT also exhibited superior flexural strength than other materials at both 24 h and 4 weeks but lower surface microhardness (p < 0.05). EF and F9 showed higher release of F, Al, and P than DT and KT. There was no statistically significant difference in fibroblast viability among the tested materials (p > 0.05). Conclusions Elastomeric micelles-containing glass ionomer cement (DT) exhibited satisfactory mechanical properties and cytocompatibility compared with other materials. DT could, therefore, potentially be considered an alternative high-strength GIC for load-bearing restorations.

Yudaev Pavel A., Chistyakov Evgeniy M.

The existing additives for dental restorative materials used in therapeutic dentistry, dentures, orthodontic appliances and adhesives (for example, metal and metal oxide nanoparticles) and also additives to root canal irrigants used in endodontics and to mouthwashes can be toxic to humans, cause allergic reactions and accumulate in organs and tissues. Today, a relevant trend is development of dental materials that have an antimicrobial effect and are non-toxic to humans. A promising alternative to the above-mentioned additives are phyto-components, including plant and propolis extracts, since they are cheap and non-toxic. This review is devoted to natural antimicrobial additives to dental materials used in orthodontics, dentures, therapeutic dentistry and endodontics. The review makes recommendations regarding additional research required for practical implementation of the considered dental materials (filling materials, mouthwashes, orthodontic adhesives and orthopaedic dental products), examines the influence of antimicrobial additives on the physicochemical and physicomechanical properties of polymer dental materials, and outlines the advantages and disadvantages of natural additives compared to synthetic ones. The main challenges in this research area are the narrow range of microorganisms for which the antimicrobial effect was studied (which are mainly S. mutans, E. faecalis, C. albicans) and the predominance of in vitro studies over clinical studies. The review covers published data of the past five years.The bibliography includes 123 references.

Ravi B., Paulraj J., Maiti S., Shanmugam R.

Alsunbul H., Khan A.A., Alqahtani Y.M., Hassan S.A., Asiri W., Saadaldin S., Alharthi R., Aldegheishem A.

This laboratory experiment was conducted with the objective of augmenting the mechanical properties of glass ionomer cement (GIC) via altering the composition of GIC luting powder through the introduction of micron-sized silanized glass fibres (GFs). Experimental GICs were prepared through the addition of two concentrations of GFs (0.5% and 1.0% by weight) to the powder of commercially available GIC luting materials. The effect of GF in set GIC was internally evaluated using micro-CT while the mechanical attributes such as nano hardness (nH), elastic modulus (EM), compressive strength (CS), and diametral tensile strength (DTS) were gauged. Additionally, the physical properties such as water solubility and sorption, contact angle (CA), and film thickness were evaluated. Reinforced Ketac Cem Radiopaque (KCR) GIC with 0.5 wt.% GF achieved improved nH, EM, CS, and DTS without affecting the film thickness, CA or internal porosity of the set GIC cement. In contrast, both GF-GIC formulations of Medicem (MC) GIC showed the detrimental effect of the GF incorporation. Reinforcing KCR GIC with 0.5 wt.% silanized GFs could improve the physical and mechanical attributes of luting material. Silanized GF, with optimal concentration within the GIC powder, can be used as a functional additive in KCR GIC with promising results.

Hamdy T.M.

Abstract Background Conventional glass ionomer cements (GICs) are currently the most widely used dental cements due to their chemical bonding into tooth structure, release of fluoride, and ease of manipulation and usage. One of their drawbacks is their low mechanical properties and high solubility. Carbon nanotubes (CNTs) could be utilized in dentistry due to their several potential applications. CNTs can be used as fillers to reinforce polymers or other materials. Additionally, silver (Ag) nanoparticles are highly effective at preventing dental biofilm and enhancing mechanical properties. Objectives The aim of the present in vitro study is to evaluate the compressive strength, surface microhardness, solubility, and antimicrobial effect of the conventional GIC reinforced with manual blending of 0.01 wt.% Ag doped CNT fillers. Methods The control group was prepared by mixing dental GIC powder with their liquid. The innovatively reinforced dental GIC group was prepared by incorporating 0.01 wt.% Ag doped CNT fillers into the GIC powder prior to liquid mixing. Chemical characterization was performed by XRF. While, physical characterization was done by measuring film thickness and initial setting time. The compressive strength, surface microhardness, solubility, and antimicrobial effect against Streptococcus mutans bacteria using an agar diffusion test were measured. The data was statistically analyzed using independent sample t-tests to compare mean values of compressive strength, surface microhardness, solubility, and antimicrobial activity (p ≤ 0.05). Results The results revealed that innovative reinforced GIC with 0.01 wt.% Ag doped CNT fillers showed higher mean compressive strength, surface microhardness, and antimicrobial effect values than the conventional GIC control group; there was no significant difference between different groups in relation to the solubility test (P ≤ 0.05). Conclusion The innovatively reinforced GIC with 0.01 wt.% Ag doped CNT fillers had the opportunity to be used as an alternative to conventional GIC dental cements.

Khalil R.J., Al-Shamma A.M.

Background. Resin-modified glass ionomer cements (RMGICs) are characterized by their ability to chemically bond with the tooth structure and their fluoride release, making them commonly used to retain indirect restorations. However, inferior mechanical properties and solubility (SO) are their main drawbacks compared to the most recent resin-based cement. Aim of the Study. Formulate a novel brand of experimental RMGIC (eRMGIC), based on RMGIC by incorporating 2-(methacryloxy) ethyl phosphate (2-MEP), an organophosphorus monomer with the potential to enhance mechanical properties along with low SO. Materials and Methods. eRMGICs were prepared by the inclusion of 2-MEP monomer with different weight percentages (0–40 wt%) into the RMGIC’s liquid (Fuji PLUS, GC. Corp.), then their compressive strength (CS), flexural strength (FS), film thickness (FT), setting time (ST), SO, and water sorption were examined and compared to the conventional RMGIC. Furthermore, a scanning electron microscope analyzed their surface homogeneity and integrity. Shapiro–Wilk test of normality was used to analyze data, one-way analysis of variance, Dunnett T3, and Tukey’s honest significant difference post-hoc tests. Results. After 28 days and 180 days of storage, the values of CS of the eRMGICs were significantly higher. However, after 24 hr of storage, the values were comparable to the control group. The FS results showed a double-fold increase in different concentrations of eRMGICs through all the time intervals ( p < 0.001 ) compared to conventional RMGIC. Furthermore, the inclusion of 2-MEP increased water uptake and decreased SO. The FT of experimental eRMGICs cement showed a statistically significant increase with increasing 2-MEP concentration. However, it was within the specification given by ISO 9917-1:2007. There was a decrease in the ST of eRMGICs compared to control cement; however, it was within the specification given by ISO 9917-2:2017. Conclusions. 2-MEP monomer showed encouraging results and could be used in producing new (eRMGICs) with enhanced physicomechanical properties, which can increase the longevity of cement and improve its ability to resist occlusal stresses without fracture.

Khan A.A., Bari A., Abdullah Al-Kheraif A., Alsunbul H., Alhaidry H., Alharthi R., Aldegheishem A.

This laboratory investigation aimed to synthesize and characterize micron-sized Gum Arabic (GA) powder and incorporate it in commercially available GIC luting formulation for enhanced physical and mechanical properties of GIC composite. Oxidation of GA was performed and GA-reinforced GIC in 0.5, 1.0, 2.0, 4.0 & 8.0 wt.% formulations were prepared in disc-shaped using two commercially available GIC luting materials (Medicem and Ketac Cem Radiopaque). While the control groups of both materials were prepared as such. The effect of reinforcement was evaluated in terms of nano hardness, elastic modulus, diametral tensile strength (DTS), compressive strength (CS), water solubility and sorption. Two-way ANOVA and post hoc tests were used to analyze data for statistical significance (p < 0.05). FTIR spectrum confirmed the formation of acid groups in the backbone of polysaccharide chain of GA while XRD peaks confirmed that crystallinity of oxidized GA. The experimental group with 0.5 wt.% GA in GIC enhanced the nano hardness while 0.5 wt.% and 1.0 wt.% GA in GIC increased the elastic modulus compared to the control. The CS of 0.5 wt.% GA in GIC and DTS of 0.5 wt.% and 1.0 wt.% GA in GIC demonstrated elevation. In contrast, the water solubility and sorption of all the experimental groups increased compared to the control groups. The incorporation of lower weight ratios of oxidized GA powder in GIC formulation helps in enhancing the mechanical properties with a slight increase in water solubility and sorption parameters. The addition of micron-sized oxidized GA in GIC formulation is promising and needs further research for improved performance of GIC luting composition.

Ge K.X., Lung C.Y., Lam W.Y., Chu C., Yu O.Y.

To develop an antimicrobial silver zeolite glass ionomer cement (SZ-GIC) and determine its biocompatibility, physical, adhesive and antibacterial properties. Silver nitrate and sodium zeolite were used to synthesize silver zeolite (SZ). SZ-GICs were prepared by incorporating SZ into GIC at 5% (SZ-GIC5), 2% (SZ-GIC2), or 1% (SZ-GIC1) by weight, respectively. The SZ-GICs were characterized by evaluating surface morphology, topography and elemental composition. SZ-GICs’ biocompatibility was assessed by evaluating cell cytotoxicity. Their physical properties were determined by testing setting time, compressive strength, flexural strength, water sorption and solubility. Their adhesive property was assessed by evaluating micro-tensile bond strength. Their antibacterial properties were assessed by evaluating biofilm growth kinetic, metabolic activity, viability and morphology. GIC was used as a control. SZ was a three-dimensional crystalline mineral. SZ-GICs (including SZ-GIC 5, 2 and 1) showed similar surface morphology and topography to GIC. SZ-GIC1 and GIC had no difference in cell cytotoxicity (p>0.05). SZ-GICs and GIC showed no difference in setting time (p>0.05). SZ-GICs had higher compressive and flexural strength than GIC (p

Aguilar-Perez D.A., Urbina-Mendez C.M., Maldonado-Gallegos B., Castillo-Cruz O.D., Aguilar-Ayala F.J., Chuc-Gamboa M.G., Vargas-Coronado R.F., Cauich-Rodriguez J.V.

Background: We assessed the effect of propolis on the antibacterial, mechanical, and adhesive properties of a commercial poly(alkenoate) cement. Methods: The cement was modified with various concentrations of propolis, and antibacterial assays were performed against S. mutans by both MTT assays and agar diffusion tests. The compressive, flexural, and adhesive properties were also evaluated. Results: the modified cement showed activity against S. mutans in both assays, although reductions in compressive (from 211.21 to 59.3 MPa) and flexural strength (from 11.1 to 6.2 MPa) were noted with the addition of propolis, while adhesive strength (shear bond strength and a novel pull-out method) showed a statistical difference (p < 0.05). Conclusion: the antiseptic potential of modified material against S. mutans will allow this material to be used in cases in which low mechanical resistance is required (in addition to its anti-inflammatory properties) when using atraumatic restorative techniques, especially in deep cavities.

Kantovitz K.R., Carlos N.R., Silva I.A., Braido C., Costa B.C., Kitagawa I.L., Nociti-Jr F.H., Basting R.T., de Figueiredo F.K., Lisboa-Filho P.N.

This study characterized TiO2 nanotube (TiO2-nt) ultrastructure and morphology, and the physicochemical impact on high-viscosity conventional glass-ionomer cement (GIC). TiO2-nt was synthesized by the alkaline method (n = 3), assessed by scanning (SEM) and transmission electron microscope (TEM), and was added (3%, 5%, 7%—in weight) to KM (Ketac Molar EasyMix™). Analyses included: SEM; Energy-dispersive spectroscopy (EDS); Raman spectroscopy (RAMAN); Setting time with Gillmore needles (ST); Color (Co); Radiopacity (XR); Water sorption (WS); and solubility (SO). Quantitative data were submitted to ANOVA and Tukey’s tests (chr = 0.05). External and internal TiO2-nt diameters were 11 ± 2 nm and 6 ± 0 nm, respectively. Data analyses showed: (i) TiO2-nt present into KM matrix, with a concentration-dependent increase of Ti levels into KM, (ii) physical interaction between KM and TiO2-nt, (iii) longer initial ST for the 7% group compared to KM and 3% groups (p ≤ 0.01), (iv) decreased luminosity and yellowness for the 5% and 7% groups, (v) 36% greater radiopacity for the 5% group compared to enamel, dentin, and KM, and (vi) lower SO values for the 5% group, with no significant differences on WS across the groups. TiO2-nt displayed physical interaction with KM matrix, and also modified SO, XR and Co, without affecting ST. This study provides information on the potential impact of TiO2-nt on GIC performance. TiO2-nt may be proposed to boost confidence among dental surgeons in terms of GIC’s handling characteristics, success rate and differential diagnostic.

Sfondrini M.F., Scribante A.

Orthodontics is a specialty of dentistry dealing with the prevention, diagnosis, and treatment of mispositioned jaws and teeth [...]

Hussein F.

A biocompatible additive to glass ionomer cement types without affecting their stability in moisture and dry conditions in demand.TiO2NPs are stable and bioactive nanoparticles that improved the mechanical properties of GICs, but their impact on water sorption and solubility remains undetermined. This study aimed to evaluate the water sorption/solubility of glass ionomer cement incorporating titanium dioxide nanoparticles (TiO2NPs) in different storage solutions over time. A total of 60 glass ionomer discs were fabricated, and they were divided into two groups (n=30); conventional glass ionomer (control), TiO2 NPs modified glass ionomer. Each group was subdivided into three subgroups according to the type of storage solution used (n=10); artificial saliva, mouthwash with alcohol, and mouthwash without alcohol. Water sorption% and solubility% were recorded after immersion of specimens in the storage solutions according to the subdivided groups; at 24 hr, 1 week, and 1 month. TiO2NPs were associated with a significant decrease in sorption% in artificial saliva at 1 week, alcohol at 24hr, and a significant decrease in solubility% in all storage solutions at 24hr and artificial saliva at 1 week. There was a significant decrease in water uptake associated with both materials in artificial saliva, also with TiO2NPs modified type in alcohol-free mouthwash. There was a gradual significant increase in solubility% for conventional GIC in artificial saliva and TiO2NPs modified type in alcohol (p≤0.05). TiO2NPs may play a promising role in improving water sorption and solubility of conventional GIC, considering the type of storage solution and time.