Smart materials in dentistry--future prospects

Evaluating Glass Ionomer Cement Longevity in the Primary and Permanent Teeth-An Umbrella Review

The aim of this umbrella review was to evaluate the longevity of glass ionomer cement (GIC) as a restorative material for primary and permanent teeth. Research in the literature was conducted in three databases (MedLine/PubMed, Web of Science, and Scopus). The inclusion criteria were: (1) to be a systematic review of clinical trials that (2) evaluated the clinical longevity of GICs as a restorative material in primary and/or permanent teeth; the exclusion criteria were: (1) not being a systematic review of clinical trials; (2) not evaluating longevity/clinical performance of GICs as a restorative material; and (3) studies of dental restorative materials in teeth with enamel alterations, root caries, and non-carious cervical lesions. Twenty-four eligible articles were identified, and 13 were included. The follow-up periods ranged from 6 months to 6 years. Different types of GICs were evaluated in the included studies: resin-modified glass ionomer cement (RMGIC), compomers, and low- and high-viscosity glass ionomer cement. Some studies compared amalgam and composite resins to GICs regarding longevity/clinical performance. Analyzing the AMSTAR-2 results, none of the articles had positive criteria in all the evaluated requisites, and none of the articles had an a priori design. The criteria considered for the analysis of the risk of bias of the included studies were evaluated through the ROBIS tool, and the results of this analysis showed that seven studies had a low risk of bias; three studies had positive results in all criteria except for one criterion of unclear risk; and two studies showed a high risk of bias. GRADE tool was used to determine the quality of evidence; for the degree of recommendations, all studies were classified as Class II, meaning there was still conflicting evidence on the clinical performance/longevity of GICs and their recommendations compared to other materials. The level of evidence was classified as Level B, meaning that the data were obtained from less robust meta-analyses and single randomized clinical trials. To the best of our knowledge, this is the first umbrella review approaching GIC in permanent teeth. GICs are a good choice in both dentitions, but primary dentition presents more evidence, especially regarding the atraumatic restorative treatment (ART) technique. Within the limitation of this study, it is still questionable if GIC is a good restorative material in the medium/long term for permanent and primary dentition. Many of the included studies presented a high risk of bias and low quality. The techniques, type of GIC, type of cavity, and operator experience highly influence clinical performance. Thus, clinical decision-making should be based on the dental practitioner's ability, each case analysis, and the patient's wishes. More evidence is needed to determine which is the best material for definitive restorations in permanent and primary dentition.

Smart Material for Smarter Dentistry

Smart materials encompass a variety of substances, including smart antimicrobial peptides, pit and fissure sealants, impression materials, cement, and sutures. These materials can change properties under specific stimuli such as temperature, stress, moisture, pH, or electric and magnetic fields. These constituents signify the commencement of a novel era or epoch in the field of smart dentistry and exhibit the potential for enhanced efficacy in the future.

Smart Biomaterials: An Evolving Paradigm in Dentistry

According to definition and general agreement, smart materials have properties that can be altered in a controlled fashion by stimuli including stress, temperature, moisture, pH, and electric or magnetic fields. Various recent materials in materials science are in working order, meaning they must achieve their tasks and should go through intentional modification. Smart materials change one or more of their characteristics in response to inputs. They can be called as responsive materials. As these materials have been available for so long, they are used for a wide range of purposes. These qualities have useful applications in many different industries, including dentistry. Zirconia, shape-memory alloys, and SmartSeal obturation system (Prosmart-DRFP Ltd., Stamford, United Kingdom) are a few examples of dental materials with intelligent behavior. The creation of novel materials is a major trend in materials science. These materials might make it possible to develop cutting-edge dental therapies with vastly improved clinical results. This article reviews the following: nickel-titanium smart alloy, smart composites, self-healing composites, smart ceramics, glass ionomer cement as a smart material, SmartSeal obturation system, and smart coatings for dental implants. We can better understand these biosmart materials with the aid of this review. The development of these newer and superior smart materials makes the outcome of the treatment far better for both the operator and the patient.

Effect of CPP-ACP Modified-GIC on Prevention of Demineralization in Comparison to Other Fluoride-Containing Restorative Materials

BACKGROUND

This study evaluated the ability of a CPP-ACP-modified GIC to inhibit demineralization around the margin of cervical cavities in natural teeth in comparison with a Giomer and conventional GIC with and without coating.

METHODS

Thirty-two sound human molars were used. Box-shaped cavities were prepared along the CEJ. Teeth were randomly divided into 4 groups and restored with Equia Forte Fil, Coated Equia Forte Fil, Fuji VII EP, or Beautifil II. Teeth were subjected to pH cycling. Micromorphological and elemental analyses were done using SEM and EDX. Polarized light microscope analysis and microhardness tests were also performed.

RESULTS

Microhardness tests on enamel showed a significant difference between the coated Equia group, Equia, and Beautifil II groups (p<0.05). Dentin results showed significant differences between the coated Equia group and all other groups (p<0.05). Elemental analysis showed significant differences in calcium weight percentage among the first and second observation levels in all groups (p<0.05). A significant difference was found between the coated Equia group and the other three groups (p<0.05).

CONCLUSIONS

All tested materials showed some ability to resist demineralization at the restoration margins. The coated GIC restoration showed better outcomes compared with the other tested materials. © 2022 Australian Dental Association.

Effect of Nanostructures on the Properties of Glass Ionomer Dental Restoratives/Cements: A Comprehensive Narrative Review

Overall perspective of nanotechnology and reinforcement of dental biomaterials by nanoparticles has been reported in the literature. However, the literature regarding the reinforcement of dental biomaterials after incorporating various nanostructures is sparse. The present review addresses current developments of glass ionomer cements (GICs) after incorporating various metallic, polymeric, inorganic and carbon-based nanostructures. In addition, types, applications, and implications of various nanostructures incorporated in GICs are discussed. Most of the attempts by researchers are based on the laboratory-based studies; hence, it warrants long-term clinical trials to aid the development of suitable materials for the load bearing posterior dentition. Nevertheless, a few meaningful conclusions are drawn from this substantial piece of work; they are as follows: (1) most of the nanostructures are likely to enhance the mechanical strength of GICs; (2) certain nanostructures improve the antibacterial activity of GICs against the cariogenic bacteria; (3) clinical translation of these promising outcomes are completely missing, and (4) the nanostructured modified GICs could perform better than their conventional counterparts in the load bearing posterior dentition.

Recent approaches in clinical applications of 3D printing in neonates and pediatrics

Neonates and pediatric populations are vulnerable subjects in terms of health. Proper screening and early optimal treatment would reduce infant and child mortality, improving the quality of life. Researchers and clinicians all over the world are in pursuit of innovations to improve the medical care delivery system. Infant morphometrics changes drastically due to the rapid somatic growth in infancy and childhood, demanding for patient-specific customization of treatment intervention accordingly. 3D printing is a radical technology that allows the generation of physical 3D products from digital images and addresses the patient-specific requirement. The combination of cost-effective and on-demand customization offers a boundless opportunity for the enhancement of neonates and pediatric health.Conclusion: The advanced technology of 3D printing proposes a pioneering breakthrough in bringing physiologically and anatomically appropriate treatment strategies addressing the unmet needs of child health problems. What is Known: • The potential application of 3D printing is observed across a multitude of fields within medicine and surgery. • The unprecedented effect of this technology on pediatric healthcare is still very much a work in progress. What is New: • The recent clinical applications of 3D printing provide better treatment modalities to infants and children. • The review provides an overview of the comparison between conventional treatment methods and 3DP regarding specific applications.

Ion release and recharge from a fissure sealant containing amorphous calcium phosphate

To assess- the release of calcium and phosphate ions from a fissure sealant containing amorphous calcium phosphate (ACP), and to determine the re-release capacity of these ions when charged with a solution containing casein phosphopeptide-amorphous calcium phosphate (CPP-ACP). Nine blocks of ACP resin-based sealant were prepared and immersed in three solutions at different pH (4.0, 5.5, 7.0), and calcium and phosphate ion release was measured with ion chromatography at 1, 3, 5, 7, 14, 21 and 28 days after immersion. Sixty days after immersion, each block was charged with CPP-ACP solution in three 7-day cycles to investigate the re-release of these ions, which was measured on days 1, 3, and 7. No difference was observed in initial calcium ion release at pH 4.0 and pH 5.5. At both values, ion release was significantly higher than at pH 7.0 (p<0.001). Initial phosphate release was significantly different among the three pH values (p<0.001). After re-charging the specimens, calcium ion re-release was greater than phosphate ion release. Initial ion release from ACP resin-based sealant was greatest at the lowest pH. Ion release decreased with time. As the number of recharge cycles increased, ion re-release also improved. Phosphate ion re-release required more recharge cycles than calcium ion re-release.

Shape-Memory Polymers in Dentistry: Systematic Review and Patent Landscape Report

OBJECTIVE

To perform a systematic review (SR) of existing literature and a patent landscape report (PLR) regarding the potential applications of shape-memory polymers (SMPs) in dentistry.

SEARCH STRATEGY

Clinical and Biomedical online databases (Pubmed, Medline via Embase, Scopus, LILACS, Web of Science, Cochrane Library), Materials Science and Engineering databases (IEEE Explore, Compendex, Proquest), Material Science and Chemical database (Reaxys) so as Patents databases (Questel-Orbit, Espacenet, Patentscope) were consulted as recently as January 2019 to identify all papers and patents potentially relevant to the review. The reference lists of all eligible studies were hand searched for additional published work.

RESULTS

After duplicate selection and extraction procedures, 6 relevant full-text articles from the initial 302 and 45 relevant patents from 497 were selected. A modified Consolidated Standards of Reporting Trials (CONSORT) checklist of 14 items for reporting pre-clinical in-vitro studies was used to rate the methodological quality of the selected papers. The overall quality was judged low.

CONCLUSIONS

Despite the great potential and versatility of SMPs, it was not possible to draw evidence-based conclusions supporting their immediate employment in clinical dentistry. This was due to the weak design and a limited number of studies included within this review and reflects the fact that additional research is mandatory to determine whether or not the use of SMPs in dentistry could be effective. Nevertheless, the qualitative analysis of selected papers and patents indicate that SMPs are promising materials in dentistry because of their programmable physical properties. These findings suggest the importance of furtherly pursuing this line of research.

Casein Phosphopeptide-Amorphous Calcium Phosphate Reduces Streptococcus mutans Biofilm Development on Glass Ionomer Cement and Disrupts Established Biofilms

Glass ionomer cements (GIC) are dental restorative materials that are suitable for modification to help prevent dental plaque (biofilm) formation. The aim of this study was to determine the effects of incorporating casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) into a GIC on the colonisation and establishment of Streptococcus mutans biofilms and the effects of aqueous CPP-ACP on established S mutans biofilms. S. mutans biofilms were either established in flow cells before a single ten min exposure to 1% w/v CPP-ACP treatment or cultured in static wells or flow cells with either GIC or GIC containing 3% w/w CPP-ACP as the substratum. The biofilms were then visualised using confocal laser scanning microscopy after BacLight LIVE/DEAD staining. A significant decrease in biovolume and average thickness of S. mutans biofilms was observed in both static and flow cell assays when 3% CPP-ACP was incorporated into the GIC substratum. A single ten min treatment with aqueous 1% CPP-ACP resulted in a 58% decrease in biofilm biomass and thickness of established S. mutans biofilms grown in a flow cell. The treatment also significantly altered the structure of these biofilms compared with controls. The incorporation of 3% CPP-ACP into GIC significantly reduced S. mutans biofilm development indicating another potential anticariogenic mechanism of this material. Additionally aqueous CPP-ACP disrupted established S. mutans biofilms. The use of CPP-ACP containing GIC combined with regular CPP-ACP treatment may lower S. mutans challenge.

Advances in Nanotechnology for Restorative Dentistry

Rationalizing has become a new trend in the world of science and technology. Nanotechnology has ascended to become one of the most favorable technologies, and one which will change the application of materials in different fields. The quality of dental biomaterials has been improved by the emergence of nanotechnology. This technology manufactures materials with much better properties or by improving the properties of existing materials. The science of nanotechnology has become the most popular area of research, currently covering a broad range of applications in dentistry. This review describes the basic concept of nanomaterials, recent innovations in nanomaterials and their applications in restorative dentistry. Advances in nanotechnologies are paving the future of dentistry, and there are a plenty of hopes placed on nanomaterials in terms of improving the health care of dental patients.

Biaxial flexural strength of high-viscosity glass-ionomer cements heat-cured with an LED lamp during setting

Adding heat to glass ionomers during setting might improve mechanical properties. The aim was to compare the biaxial flexural strength (BFS) between and within four glass ionomers, by time of exposure to a high-intensity LED light-curing unit. Materials and methods. Samples of Fuji 9 Gold Label, Ketac Molar Easymix, ChemFil Rock, and the EQUIA system were divided into three treatment groups (n = 30): without heating (Group 1), heated with LED lamp of 1400 mW/cm² for 30 s while setting (Group 2), and heated with LED lamp of 1400 mW/cm² for 60 s while setting (Group 3). Samples were stored for 48 hours in distilled water at 37°C until tested. BFS was tested, using a universal testing machine at a crosshead speed of 1 mm/min. Data were analyzed, using ANOVA test with the Bonferroni correction (α = 0.05). Heating the glass-ionomer cements with an LED curing light of 1400 mW/cm² during setting for 30 s increased the BFS value of all GICs. No statistically significant difference in mean BFS scores was found between the EQUIA system and ChemFil Rock at 30 s and 60 s. The mean BFS value was statistically significantly higher for the EQUIA system and ChemFil Rock than for Fuji 9 Gold Label and Ketac Molar Easymix at all exposure times.

Qualitative assessment of microstructure and Hertzian indentation failure in biocompatible glass ionomer cements

Discs of biocompatible glass ionomer cements were prepared for Hertzian indentation and subsequent fracture analyses. Specifically, 2 × 10 mm samples for reproducing bottom-initiated radial fracture, complemented by 0.2 × 1 mm samples for optimal resolution with X-ray micro tomography (μCT), maintaining dimensional ratio. The latter allowed for accurate determination of volumetric-porosity of the fully cured material, fracture-branching through three Cartesian axes and incomplete bottom-initiated cracking. Nanocomputed tomography analyses supported the reliability of the μCT results. Complementary 2-dimensional fractographic investigation was carried out by optical and scanning electron microscopies on the larger samples, identifying fracture characteristics. The combined 3-D qualitative assessment of microstructure and fractures, complemented by 2-D methods, provided an increased understanding of the mechanism of mechanical failure in these cements. Specifically, cracks grew to link pores while propagating along glass-matrix interfaces. The methodological development herein is exploitable on related biomaterials and represents a new tool for the rational characterisation, optimisation and design of novel materials for clinical service.

Flexural Strength and Morphological Characteristics of Resin-modified Glass-ionomer Containing Bioactive Glass

Introduction

Recent advances in dental materials have led to the production of smart materials. Recently, addition of bioactive materials to glass-ionomer cements has resulted in new capabilities beyond the beneficial effects of fluoride release. This in vitro study compared the flexural strengths (FS) of a resin-modified glass-ionomer containing bioactive glass (RMGIBAG) with that of a commonly used resin-modified glass-ionomer (RMGI).

Methods and materials

A total of forty RMGI and RMGI-BAG bars (20 × 4 × 4 mm) were prepared in stainless steel molds. Each of the RMGI and RMGI-BAG bars was set for FS test. FS values of the specimens were measured using three-point bending test at a crosshead speed of 0.5 mm/min. The surface changes and the amounts of elements on the materials’ surfaces were also evaluated by SEM/EDS analyses. Data were analyzed using SPSS 11.5 and t-test (a = 0.05).

Results

The means ± SD in the study groups were 61.46 ± 22.52 and 39.90 ± 9.11 MPa respectively. There were significant differences between FS of the two study groups (p = 0.003).

Conclusion

While adding 20 wt% of BAG to the RMGI powder evaluated in this study decreases FS of the material significantly, the mean value of FS is in the acceptable range of the reported FS values for conventional GIs and RMGIs that are commercially available for clinical use.

Clinical significance

While flexural strength of RMGI decreases subsequent to addition of bioactive glass, it is still clinically acceptable considering the flexural strength values reported for clinically used GIs and RMGIs. Further studies are recommended.

How to cite this article

Mousavinasab SM, Khoroushi M, Keshani F, Hashemi S. Flexural Strength and Morphological Characteristics of Resin-modified Glass-ionomer Containing Bioactive Glass. J Contemp Dent Pract 2011;12(1):41-46.

The ART approach: clinical aspects reviewed

The success of ART as a caries management approach is supported by more than 20 years of scientific evidence. ART follows the contemporary concepts of modern cariology and restorative dentistry. It challenges treatment concepts such as step-wise excavation and the need for complete removal of affected dentine. The ART approach so far has mainly used high-viscosity glass-ionomer as the sealant and restorative material. Cariostatic and remineralization properties have been ascribed to this material which requires further research to establish its clinical relevance. The adhesion of high-viscosity glass-ionomer to enamel in pits and fissures is apparently strong, as its remnants, blocking the pits and fissures, have been considered a possible reason for the low prevalence of carious lesion development after the glass-ionomer has clinically disappeared from it. Encapsulated high-viscosity glass-ionomers may lead to higher restoration survival results than those of the hand-mixed version and should, therefore, not be neglected when using ART. Similarly, the use of resin-modified glass-ionomer with ART should be researched. The effectiveness of ART when compared to conventional caries management approaches has been shown in numerous studies. Proper case selection is an important factor for long-lasting ART restoration survival. This is based on the caries risk situation of the individual, the size of the cavity opening, the strategic position of the cavitated tooth and the presence of adequate caries control measures. As the operator is one of the main causes for failure of ART restorations, attending a well-conducted ART training course is mandatory for successful implementation of ART.