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471,437 result(s) for "Cements"
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Dental Luting Cements: An Updated Comprehensive Review
The cementation of indirect restoration is one of the most important steps in prosthetic and restorative dentistry. Cementation aims to bond the prosthetic restoration to the prepared enamel or enamel and dentine. Successful cementation protocols prevent biofilm formation at the margin between tooth and restoration and minimize mechanical and biological complications. With the advancements in dental cements, they have been modified to be versatile in terms of handling, curing, and bond strengths. This review presents updates on dental cements, focusing on the composition, properties, advantages, limitations, and indications of the various cements available. Currently, dental restorations are made from various biomaterials, and depending on each clinical case, an appropriate luting material will be selected. There is no luting material that can be universally used. Therefore, it is important to distinguish the physical, mechanical, and biological properties of luting materials in order to identify the best options for each case. Nowadays, the most commonly used dental cements are glass-ionomer and resin cement. The type, shade, thickness of resin cement and the shade of the ceramic, all together, have a tangible influence on the final restoration color. Surface treatments of the restoration increase the microtensile bond strength. Hence, the proper surface treatment protocol of both the substrate and restoration surfaces is needed before cementation. Additionally, the manufacturer’s instructions for the thin cement-layer thickness are important for the long-term success of the restoration.
Assessment of Photocatalytic Nano-TiOsub.2 Mortars’ Behavior When Exposed to Simulated Indoor Conditions of Glazed Buildings
The application of nano-TiO[sub.2] as a photocatalytic agent in buildings’ internal surfaces has recently attracted attention to mitigate microorganism growth, soiling, and contamination in indoor environments. This work aimed at comparing the Rhodamine B (RhB) dye degradation efficiency of three different mortar compositions subjected to simulated internal radiation, in which nano-TiO[sub.2] (10 wt% of binder mass) was dispersed by ultrasonic and mechanical methods. Mortar specimens were produced with white Portland cement, hydrated lime, sand, and water in different volume proportions of 1:1:6 (cement:lime:sand), 1:3 (cement:sand), and 1:4 (cement:sand). The first stage of the research evaluated samples exposed to the natural outdoor environment and proved the efficiency of specimens’ photoactivity when covered by a glass layer. The second and principal phase of the study simulated indoor conditions in glazed buildings through artificial weathering in which the composition of 1:1:6 was mechanically dispersed and exhibited the highest global color change (ΔE) values for RhB staining. The main finding of the study was that the mortars exposed to simulated indoor conditions presented high ΔE grades, classified as easily perceived by the human eye. This demonstrates the photocatalytic efficiency in an internal building environment that receives radiation through a glass surface.
Nanocelluloses: Natural-Based Materials for Fiber-Reinforced Cement Composites. A Critical Review
Nanocelluloses (NCs) are bio-based nano-structurated products that open up new solutions for natural material sciences. Although a high number of papers have described their production, properties, and potential applications in multiple industrial sectors, no review to date has focused on their possible use in cementitious composites, which is the aim of this review. It describes how they could be applied in the manufacturing process as a raw material or an additive. NCs improve mechanical properties (internal bonding strength, modulus of elasticity (MOE), and modulus of rupture (MOR)), alter the rheology of the cement paste, and affect the physical properties of cements/cementitious composites. Additionally, the interactions between NCs and the other components of the fiber cement matrix are analyzed. The final result depends on many factors, such as the NC type, the dosage addition mode, the dispersion, the matrix type, and the curing process. However, all of these factors have not been studied in full so far. This review has also identified a number of unexplored areas of great potential for future research in relation to NC applications for fiber-reinforced cement composites, which will include their use as a surface treatment agent, an anionic flocculant, or an additive for wastewater treatment. Although NCs remain expensive, the market perspective is very promising.
Clinical evaluation of pediatric zirconia crowns cemented with two luting cements: a 12 months split-mouth randomised controlled trial
Background Several treatment options have been proposed for restoring primary teeth in children. Recently, Zirconia crowns have been introduced as an esthetic option and gained wide popularity. However, the literature is still limited regarding the clinical outcomes and luting techniques of these crowns. The aim of this study was to compare the clinical efficacy of using Glass Ionomer Cement (GIC) versus self-adhesive resin cement with anterior zirconia crowns. Materials and methods This was a split-mouth randomised clinical trial that involved healthy three-to-five-year-old children with carious primary incisors that required restoration with zirconia crowns. Pair-matched incisors were randomly assigned to receive either resin cement or GIC for crown cementation. Crowns were clinically evaluated for retention, and gingival condition at 1-week, 1-,3-, 6- and 12-month recall appointments . Results Twenty-six children were enrolled in the study with a total of 42 pair-matched incisors (i.e. 84 teeth). Follow-up durations ranged from 12 to 30 months. Over the study period, only one patient experienced crown debonding in the GIC group. Maximum retention (100%) was reported for both GIC and resin cement groups after 12 months. Regarding gingival health, no statistically significant difference was found in the gingival index scores between the two cement types at all follow-up points. Conclusion The effect of the type of cement is likely to be clinically insignificant. GIC could be considered a valid alternative to the resin-based cement for zirconia crowns in primary teeth.
Clinical and Ultrastructural Effects of Different Liners/Restorative Materials on Deep Carious Dentin: A Randomized Clinical Trial
We evaluated the effect of calcium hydroxide cement (CHC) and glass ionomer cement (GIC) on carious dentin and bacterial infections after partial caries removal and sealing. Sixty permanent teeth with deep lesions underwent partial caries removal, the application of CHC, GIC or wax, i.e. negative control (NC), and were then sealed for 3–4 months. After the partial caries removal and the sealing period, the dentin was clinically assessed (colour and consistency) and analysed by scanning electron microscopy to assess dentin organization and bacterial infections. The effect of the treatment in each group was assessed by the Wilcoxon and χ 2 tests, differences among groups by the Kruskal-Wallis test and the correlations between variables by Spearman correlation. No clinical symptoms or radiographic signals of pulpits or pulp necrosis were observed during the study. Dentin darkening was observed after the sealing period in the CHC and NC groups (p < 0.05). However, there was no difference in the colour after treatment among the 3 groups (p > 0.05). Dentin hardening occurred in all groups after treatment (p < 0.05), also with no differences (p > 0.05). Dentin samples showed better organization after the sealing period than after partial caries removal, with total or partial obliteration of dentinal tubules (CHC p < 0.03, GIC p < 0.05, NC p < 0.01) and a reduction of bacterial infections (CHC p < 0.03, GIC p < 0.05, NC p < 0.03). No differences were observed. Correlations between the different criteria, except for colour and bacterial infection, were detected in all cases. Partial caries removal and sealing resulted in dentin hardening, decreased bacterial numbers and dentin reorganization, irrespective of the dentin protection used.
Clinical and radiographic evaluation of Portland cement added to radiopacifying agents in primary molar pulpotomies
Aim This was to evaluate the clinical and radiographic outcomes of Portland cement (PC) added to radiopacifying agents in primary molar pulpotomies. Methods Thirty primary mandibular molars of children aged between 5 and 9 years were randomly assigned to the following groups: PC; PC with iodoform (PC + CHI 3 ); PC with zirconium oxide (PC + ZrO 2 ) and treated by pulpotomy technique. Clinical and radiographic follow-up assessments were performed at 6, 12 and 24 months. Statistical analysis was performed by Fisher’s exact test ( P  < 0.05). Results The clinical and radiographic evaluations showed 100 % success rates, and the results showed no statistically significant difference between groups. Conclusions According to this study, PC added to radiopacifying agents exhibited satisfactory clinical and radiographic results in primary molar pulpotomies.
A simple method for determining the total amount of physically and chemically bound water of different cements
For Portland cements, Powers’ model provides a simple method for calculating the total amount of water bound by cement hydration (both physically and chemically bound). On the other hand, no such simple model is available for other types of cements that are of increasing interest, such as calcium aluminate cements and calcium sulfoaluminate cements. The main uncertainty for these types of cement regards the amount of physically bound water in the hydrates, while the amount of chemically bound water can be calculated, e.g., by thermodynamic modeling. In this paper, a simple approach for estimating the total amount of bound water of different cements is presented. This novel approach consists in measuring the rate of heat liberation of cement pastes made with the same cement, starting at low water-to-cement ratio (w/c) and increasing it steadily. As the cumulative heat of hydration reaches a plateau for a given w/c and does not increase for further increases in the water amount, this w/c is interpreted as total water demand of the cement. The method is tested with a Portland cement, showing that it is in broad agreement with Powers’ model. First results for calcium aluminate cement and calcium sulfoaluminate cement are presented, from which estimations of the amount of physically and chemically bound water are obtained.
Update on Dental Luting Materials
A dental luting material aids in the retention and stability of indirect restorations on the prepared tooth structure. In dentistry, clinicians are using a wide range of luting materials for the cementation of indirect restorations. Zinc oxide eugenol and non-eugenol cements, zinc phosphate cement, zinc polycarboxylate cement, glass ionomer cement and resin cements are common dental cements used in dentistry. Each luting material or cement possesses unique properties and clinical implications. An ideal luting cement should be biocompatible, insoluble, resistant to thermal and chemical assaults, antibacterial, aesthetic, simple and easy to use. It should have high strength properties under tension, shear and compression to resist stress at the restoration–tooth interface, as well as adequate working and setting times. So far, no luting material possesses all of these properties of an ideal cement. Scientists have been modifying the conventional luting cements to improve the material’s clinical performance and developing novel materials for clinical use. To achieve the best clinical outcome, clinicians should update their knowledge and gain a good understanding of the luting materials so that they can make a wise clinical decision on the material selection and obtain an insight into the development of luting cements. Therefore, the objective of this study is to provide a discussion on the physical, chemical, adhesive and aesthetic properties of common luting materials. The clinical indications of these luting materials are suggested based on their properties. In addition, overviews of the modification of the conventional luting materials and the newly developed luting materials are provided.
Effect of addition of nano-magnetite on the hydration characteristics of hardened Portland cement and high slag cement pastes
In this investigation the effect of addition of magnetite nanoparticles on the hydration characteristics of both ordinary Portland cement (OPC) and high slag cement (HSC) pastes was studied. The cement pastes were prepared using a water/solid (W/S) mass ratio of 0.3 with addition of 0.05, 0.1, and 0.3 % of magnetic fluid Fe3O4 nanoparticles by mass of cement. An aqueous stable magnetic fluid containing Fe3O4 nanoparticles, with a mean diameter in the range of super-paramagnetism, was prepared via co-precipitation method from ferrous and ferric solutions. The admixed magnetite-cement pastes were examined for compressive strength, chemically combined water content, X-ray diffraction analysis, and differential scanning calorimetry. The results of compressive strength revealed that the hardened pastes made from OPC and HSC admixed with different amounts of magnetic fluid have higher compressive strength values than those of the neat cement OPC and HSC cement pastes at almost all ages of hydration. The results of chemically combined water content for the admixed cement pastes showed almost the same general trend and nearly comparable values as those of the neat cement pastes. From the XRD diffractograms obtained for the neat OPC and HSC cement pastes, the main hydration products identified are calcium silicate hydrates, portlandite, and calcium sulfoaluminate hydrates. Addition of magnetic fluid nanoparticles to both of OPC and HSC did not affect the main hydration products of the neat OPC or HSC cement in addition to one main basic difference, namely, the formation of calcium iron hydroxide silicate as a new hydration product with a reasonable hydraulic character.
Survival rate and treatment success of glass fiber posts cemented with two adhesive cementation strategies after up to 106 months: a randomized clinical trial
ObjectivesThe objective of this study is to evaluate the longevity of two fiber post cementation strategies in a prospective, multicenter, non-inferiority, double-blind randomized controlled trial.MethodsA total of 152 teeth, with adequate endodontic treatment and loss of coronal structure and bilateral simultaneous posterior occlusal contacts, were randomly allocated to receive glass fiber posts cemented with a conventional cementation strategy (CRC group: adhesive system + resin cement) (Adper Single Bond + RelyX ARC; 3 M-ESPE) or a self-adhesive cementation strategy (SRC group: self-adhesive resin cement; RelyX U100/U200; 3 M-ESPE). The patients were recalled annually for clinical and radiographical evaluation with a 93% recall rate (142 teeth, with 74 at CR groups and 68 at SRC group). The primary outcome was survival rate, considering the fiber post debonding (loss of retention). The secondary outcome included the success rate of the prosthetic treatment with crown debonding, post fracture, and tooth loss (not related to post failure). Both outcomes were evaluated annually. The Kaplan–Meier method and Cox regression with 95% confidence interval were used for the statistical analysis.ResultsFor the primary outcome (failures directly related to fiber posts cementation strategy), there were 4 fiber post debondings (2 per group), 8 root fractures (3 for SRC group and 5 for CRC group), and one mixed failure (debonding combined with root fracture for CRC), with both strategies presenting similar survival rates (p = 0.331), with 88.9% for the CRC group and 90.9% for the SRC group. For the secondary outcome (failures not related to fiber post cementation strategies), there were 8 crown debondings, 3 post fractures, and 3 tooth losses, with no statistically difference between groups (p = 0.701), with 77% for SRC and 82% for CRC.ConclusionFiber post cementation strategies with conventional or self-adhesive resin cement presents similar tooth survival and success rates.Trial registrationNCT01461239Clinical relevanceBoth adhesive cementation strategies led to high survival and success rates and are indicated for fiber post cementation, even after a long follow-up period (up to 106 months).