Background: This study evaluated mechanical properties of glass ionomer cements (GICs) used for atraumatic restorative treatment. Wear resistance, Knoop hardness (Kh), flexural (Fs) and compressive strength (Cs) were evaluated. The GICs used were Riva Self Cure (RVA), Fuji IX (FIX), Hi Dense (HD), Vitro Molar (VM), Maxxion R (MXR) and Ketac Molar Easymix (KME).

Methods:  Wear was evaluated after 1, 4, 63 and 365 days. Two-way ANOVA and Tukey post hoc tests (P = 0.05) analysed differences in wear of the GICs and the time effect. Fs, Cs, and Kh were analysed with one-way ANOVA.

Results:  The type of cement (p < 0.001) and the time (p < 0.001) had a significant effect on wear. In early-term wear and Kh, KME and FIX presented the best performance. In long-term wear, Fs and Cs, KME, FIX and HD had the best performance. Strong explanatory power between Fs and the Kh (r2 = 0.85), Cs and the Kh (r2 = 0.82), long-term wear and Fs of 24 h (r2 = 0.79) were observed.

Conclusions:  The data suggested that KME and FIX presented the best in vitro performance. HD showed good results except for early-term wear.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1834-7819.2009.01125.x

Physical-mechanical properties of glass ionomer cements indicated for atraumatic restorative treatment.

Minimum intervention dentistry (MID) is the modern medical approach to the management of caries, utilizing caries risk assessment, and focusing on the early prevention and interception of disease. Moving the focus away from the restoration of teeth allows the dentist to achieve maximum intervention, with minimal invasive treatments. The four core principles of MID can be considered to be: (1) Recognition - early identification and assessment of potential caries risk factors through lifestyle analysis, saliva testing and using plaque diagnostic tests; (2) Reduction - to eliminate or minimize caries risk factors by altering diet and lifestyle habits and increasing the pH of the oral environment; (3) Regeneration - to arrest and reverse incipient lesions, using appropriate topical agents including fluorides and casein phosphopeptides-amorphous calcium phosphates (CPP-ACP); (4) Repair - when cavitation is present and surgical intervention is required, conservative caries removal is carried out to maximize the repair potential of the tooth and retain tooth structure. Bioactive materials are used to restore the tooth and promote internal healing of the dentine. Effective implementation of MID involves integrating each of these four elements into patient assessment and treatment planning. This review paper discusses the key principles of MID as a philosophy of patient care, and the practical objectives which flow into individual patient care.

/pdf/minimum-intervention-dentistry-principles-and-objectives-14skidxeay.pdf

Minimum intervention dentistry principles and objectives

The aims of this study were to improve the mechanical and chemical properties of conventional restorative glass ionomer cement (GIC) by adding hydroxyapatite (HAp) preparations with different characteristics, and to investigate the underlying reaction mechanisms. Fuji IX GP® was used as the control GIC. The experimental GICs consisted of four HAp-particles with different characteristics added at 8 mass% to Fuji IX-powder. All cements were prepared by mixing with Fuji IX-liquid (P/L=3.6). Four HAp-particles were analyzed, and then the mechanical strengths and the fluoride-ion- release-recharge-behaviors of five GIC groups were evaluated. The results of this study demonstrate that the addition of HAp particles with highly reactive properties such as high specific surface area can enhance the flexural strength and fluoride ion release properties of conventional restorative GIC. Our results further indicate that HAp functions as an adsorbent and an ion exchangeable agent, resulting in improved mechanical and chemical properties of GIC.

/pdf/hydroxyapatite-particle-characteristics-influence-the-54ohj0jk7y.pdf

Hydroxyapatite particle characteristics influence the enhancement of the mechanical and chemical properties of conventional restorative glass ionomer cement.

Remineralization of demineralized dentin lesions adjacent to glass-ionomer cements (GICs) has been reported in the literature. This study tested the hypothesis that a strontium-based GIC can remineralize completely demineralized dentin by nucleation of new apatite crystallites within an apatite-free dentin matrix. Human dentin specimens were acid-etched, bonded with Fuji IX(GP), and immersed in a calcium-and-phosphate-containing 1.5X simulated body fluid (SBF) for 1-4 months. Polyacrylic acid and polyvinylphosphonic acid biomimetic analogs were added to the SBFs to create 2 additional remineralization media. Specimens were processed by transmission electron microscopy (TEM). No apatite deposition could be identified in the completely demineralized dentin in any of the specimens immersed in the 3 remineralization media, despite TEM/EDX evidence of diffusion of ions specific to the strontium-based GIC into the demineralized dentin. The hypothesis was rejected; mineral concentration alone is not a sufficient endpoint for assessing the success of contemporary remineralization strategies.

/pdf/failure-of-a-glass-ionomer-to-remineralize-apatite-depleted-51o26mh58r.pdf

Failure of a Glass Ionomer to Remineralize Apatite-depleted Dentin:

Every year a million tonnes of calcium rich agro and industrial waste are generated around the whole globe. These calcium rich waste like finger citron, shells of cockle, mussel, oysters etc., and egg shell are biological sources which have various organic compounds. The inorganic calcium rich waste includes gypsum, dolomite, sludge etc., which are produced in surplus amount globally. Most of these by-products are mainly dumped, while few are used for land-filling purposes which leads to the pollution. These agro and industrial by-products could be processed for the recovery of calcium carbonate and calcium oxide particles by physical and chemical method. The recovery of calcium carbonate and calcium oxide particles from such by products make them biocompatible. Moreover, the products are economical due to their synthesis from waste materials. Here, in this current review work we have emphasized on the all the calcium rich agro industries and industrial by products, especially their processing by various approaches. Further, we have also focused on the properties and application of such calcium carbonate and oxide particles for the remediation of organic and inorganic pollutants from the environments. The recovery of such particles from these byproducts is considered not only economical and eco-friendly but it also minimizes the pollution present in the form of solid waste.

The Processing of Calcium Rich Agricultural and Industrial Waste for Recovery of Calcium Carbonate and Calcium Oxide and Their Application for Environmental Cleanup: A Review

Background: There have been concerns about the dissolution of conventional glass ionomer cement (GIC) and its possible degradation when exposed to an acidic environment over time. The objective of this study was to investigate the effects of exposure of Fuji IX Fast to the simulated acidic aspects of the oral environment in terms of any changes in the elemental composition of strontium (Sr), phosphorus (P), calcium (Ca) and fluorine (F) which resulted at the surface of this material. Methods: Sixty-five cylindrical blocks of Fuji IX Fast were prepared using split moulds. The demineralizing solution was an acetate buffered demineralizing solution at pH 4.3. The remineralizing solution was a buffered solution containing 1.5 mM Ca, 0.9 mM P and 10 ppm F at pH 7. The blocks of Fuji IX Fast were subjected either to two-day alternating cycles of remineralization and demineralization for up to 24 days (test); 6 two-day cycles of demineralizing or remineralizing solution separately, or deionized distilled water alone (controls) or were left untreated (base line control). Mineral profiles of Ca, P, Sr and F within 100 μm of the material surface were assessed following 8, 16 and 24 days of treatment (test); 4, 8 or 12 days (controls) or for baseline control samples, using electron probe microanalysis (EPMA). Results: There were significant changes in mineral profile in the test specimens in terms of Sr and Ca concentrations. A molecule for molecule exchange of these elements resulted between GIC and eluant solutions. Fluoride loss from the GIC occurred to the level comparable with uptake levels recorded in eluant solutions from previous studies. The ionic exchanges appeared to be the result of dissolution followed by an equilibrium-driven diffusion. These exchanges were superficial though substantial. Conclusions: Simulated exposure of Fuji IX to the oral environment resulted in an exchange of Ca from the bathing solutions into Fuji IX to replace any Sr which was lost to the GIC. Fluorine loss from the GIC followed previously described patterns. The possible clinical significance of this exchange was discussed.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1834-7819.2007.tb00502.x

Effect of remineralization/demineralization cycles on mineral profiles of Fuji IX Fast in vitro using electron probe microanalysis.

Aim: To evaluate the shear bond strength between the dentin substrate and computer-aided design and computer-aided manufacturing feldspathic ceramic and nano resin ceramics blocks cemented with resin cement. Materials and Methods: Sixty cuboidal blocks (5 mm × 5 mm × 5 mm) were fabricated in equal numbers from feldspathic ceramic CEREC ® Blocs PC and nano resin ceramic Lava™ Ultimate, and randomly divided into six groups (n = 10). Each block was cemented to the dentin of 60 extracted human premolar using Variolink ® II/Syntac Classic (multi-steps etch-and-rinse adhesive bonding), NX3 Nexus ® (two-steps etch-and-rinse adhesive bonding) and RelyX™ U200 self-adhesive cement. All specimens were thermocycled, and shear bond strength testing was done using the universal testing machine at a crosshead speed of 1.0 mm/min. Data were analyzed using one-way ANOVA. Results: Combination of CEREC ® Blocs PC and Variolink ® II showed the highest mean shear bond strength (8.71 Mpa), while the lowest of 2.06 Mpa were observed in Lava™ Ultimate and RelyX™ U200. There was no significant difference in the mean shear bond strength between different blocks. Conclusion: Variolink ® II cement using multi-steps etch-and-rinse adhesive bonding provided a higher shear bond strength than the self-adhesive cement RelyX U200. The shear bond strength was not affected by the type of blocks used.

Shear bond strength of computer-aided design and computer-aided manufacturing feldspathic and nano resin ceramics blocks cemented with three different generations of resin cement.

Objectives This study evaluates the efficacy and safety of the professionally prescribed and nonprescription over-the-counter (OTC) bleaching agents. Materials and
 Methods Extracted human upper central incisors were prepared and stained with red wine for 14 days before being subjected to four different bleaching agents: professionally prescribed opalescence PF 15%, VOCO Perfect Bleach 10%, nonprescription OTC Crest 3D Whitestrips, and Whitelight Teeth Whitening System. Colorimetric measurement was performed with Vita Easyshade Handheld Spectrophotometer, enamel surface microhardness measured using Vickers Hardness machine, and surface roughness was evaluated with profilometer, before and after bleaching. Scanning electron microscope (SEM) evaluation and atomic force microscopy were conducted postbleaching. Statistical Analysis The data were analyzed with t-test, two-way ANOVA, one-way ANOVA, and Turkey’s test at a significance level of 5%. Results All bleaching products have the same efficacy to whiten stained enamel. Opalescence PF 15% showed significant increase in the microhardness (92.69 ± 68.316). All groups demonstrated significant increase in surface roughness (p Conclusion Professionally prescribed bleaching agent of Opalescence PF 15% is effective tin whitening the teeth, while the other bleaching products may be effective but also have deleterious effects on the enamel.

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Nonprescription Bleaching versus Home Bleaching with Professional Prescriptions: Which One is Safer? A Comprehensive Review of Color Changes and Their Side Effects on Human Enamel.

Cockle shells are a natural reservoir of calcium carbonate (CaCO3), which is widely used in bone repair, tissue scaffolds, and the development of advanced drug delivery systems. Although many studies report on the preparation of CaCO3, the development of a nanosized spherical CaCO3 precursor for calcium oxide (CaO) that is suitable to be incorporated in dental material was scarce. Therefore, this study aimed to synthesize a nanosized spherical CaCO3 precursor for CaO derived from cockle shells using a sol–gel method. Cockle shells were crushed to powder form and mixed with hydrochloric acid, forming calcium chloride (CaCl2). Potassium carbonate (K2CO3) was then fed to the diluted CaCl2 to obtain CaCO3. The effect of experimental parameters on the morphology of CaCO3, such as volume of water, type of solvents, feeding rate of K2CO3, and drying method, were investigated using field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffractometry (XRD), Brunauer–Emmett–Teller surface area analysis, and thermogravimetric analysis. Optimized CaCO3 was then calcined to form CaO. XRD analysis of CaCO3 nanoparticles was indicative of the formation of a calcite phase. The well-structured spherical shape of CaCO3 was obtained by the optimum condition of the addition of 50 mL of water into CaCl2 in ethanolic solution with a 1 h feeding rate of K2CO3. Less agglomeration of CaCO3 was obtained using a freeze-drying technique with the surface area of 26 m2/g and average particle size of 39 nm. Spherical shaped nanosized CaO (22–70 nm) was also synthesized. The reproducibility, low cost, and simplicity of the method suggest its potential applications in the large-scale synthesis of the nanoparticles, with spherical morphology in an industrial setting.

Synthesis and Characterization of Spherical Calcium Carbonate Nanoparticles Derived from Cockle Shells

Numerous studies have been conducted in the previous years with an objective to determine the ideal biomarker or set of biomarkers in temporomandibular disorders (TMDs). It was recorded that tumour necrosis factor (TNF), interleukin 8 (IL-8), IL-6, and IL-1 were the most common biomarkers of TMDs. As of recently, although the research on TMDs biomarkers still aims to find more diagnostic agents, no recent study employs the biomarker as a targeting point of pharmacotherapy to suppress the inflammatory responses. This article represents an explicit review on the biomarkers of TMDs that have been discovered so far and provides possible future directions towards further research on these biomarkers. The potential implementation of the interactions of TNF with its receptor 2 (TNFR2) in the inflammatory process has been interpreted, and thus, this review presents a new hypothesis towards suppression of the inflammatory response using TNFR2-agonist. Subsequently, this hypothesis could be explored as a potential pain elimination approach in patients with TMDs.

Zuryati Ab-Ghani

Papers

Effect of remineralization/demineralization cycles on mineral profiles of Fuji IX Fast in vitro using electron probe microanalysis.

Shear bond strength of computer-aided design and computer-aided manufacturing feldspathic and nano resin ceramics blocks cemented with three different generations of resin cement.

Nonprescription Bleaching versus Home Bleaching with Professional Prescriptions: Which One is Safer? A Comprehensive Review of Color Changes and Their Side Effects on Human Enamel.

Synthesis and Characterization of Spherical Calcium Carbonate Nanoparticles Derived from Cockle Shells

Biomarkers for Temporomandibular Disorders: Current Status and Future Directions