Concrete vs. Ceramic Blocks: Environmental Impact Evaluation Considering a Country-Level Approach

In continental countries, building materials are often moved over long distances from factories to building sites. This is especially important when quality and performance certification systems are required for the building materials’ acquisition. In this scenario, the transportation phase tends to have a great contribution to building materials’ environmental impacts. Taking into consideration that countries such as China, India, and Brazil, i.e., continental countries, are expecting the largest future housing demand, the issue of transportation will have a crucial role in environmental impacts. Through a Brazilian case study, the present work investigates the potential environmental impacts of structural masonry made of concrete and ceramic blocks certified by the Brazilian Quality Program. A cradle-to-site Life-Cycle Assessment (LCA) is carried out while considering a country-level approach using data from the literature and Ecoinvent. The results show that ceramic blocks are preferable for most states and scenarios. Human Health and Ecosystem Quality are the two categories most affected by transportation, and they can reach more than 96% and 99%, respectively. The efficiency of the building material transportation system plays an important role in reducing greenhouse gas emissions. A shift in building components from concrete to ceramic blocks has the potential to mitigate between 154 and 229 Mt CO2-eq between 2020 and 2050. The methodological approach used in this work can be applied to other building materials and other countries, especially those of continental dimensions that are expected to have a significant future housing demand.

Analysis of heat fluxes in ceramic block type building pieces

In Norte de Santander, Colombia, there is a ceramic cluster made up of 59 companies dedicated to the production of construction materials derived from clay, a vernacular material with a wide extraction potential in the region. Fired clay products in different hollow block presentations represent 15% of industrial production, these construction pieces are low cost and show a high demand in the local masonry market, therefore, their thermo-physical characteristics largely build the thermal envelope of “Cucuteña”. This research comparatively evaluates the thermal behavior of four types of ceramic blocks with different perforations, applying the finite element method in thermal simulations that consider a conductivity of 0.407 W/m°C in the ceramic to establish the influence of the shape on the temperature distribution and heat flow profiles of each piece subjected to environmental conditions of a warm semi-arid climate, with average maximum temperatures of 33 °C and an average maximum solar radiation of 796.8 Wh/m2 under extreme climatic conditions in the city of San Jose de Cúcuta, Colombia. The results of the study allow identifying the ceramic block of 6 rectangular holes as the product that, due to its physical characteristics, presents a better alternative to be applied in constructions that seek thermal efficiency.

Analysis of the optimization of the construction process of ecological brick compared to ceramic brick

The brick is composed of water, soil and cement, having an easy manufacturing process, with short construction and low cost is not subjected to burning is manufactured by a very different process from ceramic blocks, the same goes through a hydraulic press. This type of brick has characteristics that provide quality, sustainability, beauty, and above all savings in the total cost of the work. When used in construction are eliminated some steps and the execution time in the work. A block wall or ceramic brick will need roughcast, sketch, plaster, seamer and painting, besides considering the cost of these materials can not forget the labor that corresponds to an average 50% of the value of the work. But the great advantage over the other bricks is its construction system, once raised the wall this is ready, does not need finishing, and the pillar structure and beams are ready with it. Electrical and Hydraulic Installations are easily installed without the need for breakage and waste. These bricks do not require the use of mortars for laying, coatings such as plastering for regularization and finishing of walls, in addition to accelerating the work with their fittings that facilitate the alignment and plumb of the walls. The objective of this work is present through a literature review of optimization processes that involve the ecological brick. in addition to accelerating the work with their fittings that facilitate the alignment and plumb of the walls. The objective of this work is present through a literature re-view of optimization processes that involve the ecological brick. in addition to accelerating the work with their fittings that facilitate the alignment and plumb of the walls. The objective of this work is present through a literature review of optimization processes that involve the ecological brick.

Comparative Evaluation of Adaptation of Esthetic Prefabricated Fiberglass and CAD/CAM Crowns for Primary Teeth: Microcomputed Tomography Analysis

Adaptation is an important factor for the clinical success of restorations. However, no studies are available evaluating the adaptation of primary crowns. The aim of this study was to compare the adaptation of crowns fabricated by CAD/CAM technology versus prefabricated fiberglass primary crowns. Typodont maxillary central, canine, and mandibular molar teeth were prepared to serve as master dies after the size of Figaro crowns was determined ( n = 10 ). Master dies were scanned with an intraoral scanner, and 10 identical CAD/CAM crowns were fabricated from resin-ceramic blocks. Figaro and CAD/CAM crowns were placed on the corresponding master dies and scanned via micro-CT. Three-dimensional volumetric gap measurements were performed to evaluate the overall adaptation. A total of 255 location-based linear measurements were allocated into 4 categories: marginal, cervical-axial, middle-axial, and occlusal. Statistical analyses were performed with factorial ANOVA, repeated measure ANOVA, and LSD tests ( α = 0.05 ). CAD/CAM crowns showed significantly lower overall and location-based gap measurements than Figaro crowns regardless of tooth number ( p < 0.05 ). For all groups, mean marginal discrepancies were lower than occlusal measurements ( p < 0.05 ). Both crown types showed higher marginal gaps for molar teeth than for canine and central incisors with no significant difference between them ( p > 0.05 ). CAD/CAM-fabricated crowns showed better marginal and internal adaptation than prefabricated Figaro crowns.

Effects of Simulated Gastric Acid Exposure on Surface Topography, Mechanical and Optical Features of Commercial CAD/CAM Ceramic Blocks

Gastric acid exposure produces tooth structure demineralization and dental ceramic degradation. The most affected patients are those who suffer from gastroesophageal reflux disease, bulimia nervosa, and pregnant women with prolonged severe nausea. In order to protect this kind of patient, the purpose of this study was to determine whether simulated gastric acid exposure leads to microstructural changes in surface topography, hardness, color changes, and translucency of some ceramic materials, which are already on the market. Forty disks (Triluxe Forte, Cerasmart, Enamic and Empress CAD) were analyzed before and after immersion in simulated gastric acid juice, in terms of microhardness, surface roughness, translucency, and surface morphology using scanning electron microscopy. Color change was assessed by using a spectrophotometer based on CIELab parameters and the results showed that, after exposure, ∆Eab remained under the threshold of acceptability and perceptibility. In terms of microhardness, Cerasmart is the only material that did not undergo changes after immersion. SEM images illustrated observable changes surface topography after acid exposure for all the tested materials. In conclusion, Triluxe Forte suffered the most important changes after simulated gastric acid juice exposure, and Cerasmart proved to be the least affected material.

COMPARATIVE STUDY OF THE TENSILE BOND STRENGTH OF RENDERING MORTARS IN CERAMIC AND CONCRETE STRUCTURAL BLOCKS

The tensile bond strength is one of the main properties of rendering mortars. It represents the adhesiveness ability between the mortar itself and the substrate. This property depends on several factors, such as the proportion and characteristics of the mortar materials and the substrate, along with the mode of application and climate conditions. The purpose of this paper was to analyze the tensile bond strength between three rendering mortar proportions in volume – 1: 1: 6, 1: 2: 9, and 1: 6 (with plasticizer additive) – each one applied on two substrates, ceramic structural blocks with roughcast and concrete structural blocks. The rendering mortars had their physical properties evaluated in fresh and hardened stages, as well as their compressive and tensile strengths in flexure. The tensile bond strength was determined by a pullout test on ceramic and concrete masonry walls exposed to external weather. The results showed that the 1: 1: 6 mixed mortar exhibited higher tensile bond strength in both substrates of ceramic blocks with roughcast and concrete blocks without preparation. Besides, among 1: 2: 9 and 1: 6 mortars there is no significant difference in tensile bond strength considering both substrates. Another conclusion was that the substrate type did not affect the final bond strength between the mortars.

Evaluating the masking ability of CAD/CAM hybrid ceramics with different thicknesses

Aim: A discoloration existing under the restoration can affect the final restoration color, and various techniques can be used to address this situation. The aim of this study was to investigate the masking ability of the substructure, color of different hybrid CAD/CAM ceramics in various thicknesses. Methodology: A total of 120 samples were produced from 4 different CAD/CAM hybrid ceramic blocks (Cerec blocs, GC Cerasmart, Vita Enamic, 3M Lava Ultimate) in 1, 1.5 and 2 mm thickness. The samples were sliced with 100 N pressure in a low-speed precision cutting device under water cooling. The specimens were placed over the neutral grey background for initial spectrophotometric measurements. A3 color posterior nanohybrid composite (14 X 7 X 1 mm) was preferred to mimic discoloration in the substructure. The cementation procedure of composite and the CAD/CAM hybrid ceramic complex was standardized under 10 N continuous pressure and was performed using a dual cured resin cement. All samples were incubated at 37 °C for 24 hours in incubator after cementation. And the second spectrophotometeric measurement was done via the L*, a*, and b* color attributes of the complex specimens. Additionally, ΔE* values were calculated to determine the color differences between each group. Kruskal Wallis test was used for statistical analysis and Dunn’s test was used for group comparison. Significance was evaluated at least p <0.05. Results: It was found that thickness of the ceramics increases, the substructure color is better masked and the thickness made a statistically significant difference on the masking ability (p<0.01). For 1 mm thick samples, the highest ΔE* value was found in Cerec blocs with 9.36, while the lowest value was found in GC Cerasmart as 4.27. Conclusion: Within the limitations of this study, it was concluded that the tested CAD/CAM hybrid ceramics showed better masking ability than Cerec blocs. How to cite this article: Ünalan Değirmenci B, Wahid WF. Evaluating the masking ability of CAD/CAM hybrid ceramics with different thicknesses. Int Dent Res 2021;11(2):114-20. https://doi.org/10.5577/intdentres.2021.vol11.no1.9 Linguistic Revision: The English language in this manuscript has been checked by at least two professional editors, both native speakers of English.

Hardness of Resin Cements Polymerized through Glass-Ceramic Veneers

(1) Background: The aim of this study is to evaluate the hardness of resin cements polymerized through ceramic disks under different process factors (ceramic type and thickness, light-polymerization units and polymerization time); (2) Method: Three types of ceramic blocks were used (IPS e.max CAD; Celtra Duo; VITABLOCS). Ceramic disks measuring 0.5 mm, 1.0 mm and 1.5 mm were cut from commercial blocks. Two resin cements (Rely X Veneer and Variolink Esthetic) were polymerized through the ceramic specimens using distinct light-polymerization units (Deep-cure; Blue-phase) and time intervals (10 and 20 s). Hardness of cement specimens was measured using microhardness tester with a Knoop indenter. Data were statistically analyzed using factorial ANOVA (α = 5%); (3) Results: Mean microhardness of Rely X Veneer cement was significantly higher than that of Variolink Esthetic. Deep-cure resulted in higher mean microhardness values compared to Blue-phase at 0.5- and 1-mm specimen thicknesses. Moreover, a direct correlation was found between polymerization time and hardness of resin cement; (4) Conclusions: Surface hardness was affected by resin cement type and ceramic thickness, and not affected by ceramic types, within evaluated conditions. Increasing light-polymerization time significantly increased the hardness of the cement.

Attenuation Measurement of Ceramic Blocks Wall Using X-Band Waves

Nowadays, many companies depend on good communication between their technologies and Wi-Fi signal, which are part of the X-waves frequencies. Communication may suffer interference due to wave propagation’s difficulty, mainly depending on the number of walls and where the building is located. Therefore, buildings should be adapted to avoid this interference in order to minimize signal losses. Interference in wave propagation depends not only on walls but also on their structure. The studies of building construction and wave propagation may be complementary since the structure and organization may negatively affect the signal strength. This work analyzes X-waves’ attenuation (from 8GHz up to 12 GHz) in ceramic walls to evaluate their effects on wave propagation. This work differs from Literature not only by the material used, considering that there are many jobs involving concrete blocks, but also by calculating the wave signal focusing on a loss function in the analyzed object, enabling anomalous behavior analysis. This propagation behavior allows evaluating the most valuable equipment in a house (wireless device, TV). Finally, ceramic blocks were studied because they have a low cost, they are lightweight, easy to handle, and have a high frequency of use. The tests were performed in an 80cm x 80cm wall. The x-waves were produced by two horn antennas (transmitter and receiver) located at 70 cm of the wall on opposite sides and directions. We found an enhancement of attenuation in the x-waves frequency band with a significant drop at 11GHz. The signal drop mainly occurs due to the material characteristics, a.k.a stop band. This drop is caused by the electromagnetic band structure produced by the difference between the dielectric constant of the ceramic blocks and their periodically repeated voids called Electromagnetic Band Gap structure.