[Types and colors of 1 374 chair-side CAD/CAM all-ceramic restorations].

PURPOSE: To analyse the types of chairside CAD/CAM all-ceramic restorations and the color range of all-ceramic materials used so as to provide reference for the application of clinical chairside all-ceramic restoration and the color selection of all-ceramic materials. METHODS: IPS e.max CAD prostheses and related data were collected from January 2021 to December 2021 from the Department of Prosthodontics, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine. The number and type of restorations and the color of materials were investigated and analyzed by descriptive statistics. RESULTS: A total of 1 374 restorations were included, of which 624 were crown restorations, accounting for 45.41% of the total restorations. 516 cases were veneer, accounting for 37.55%; 219 were inlays, accounting for 15.94%; fixed bridges were all adhesive bridges, with the least number with only 15 cases, accounting for 1.09%. In terms of the selection of restoration materials, the use rate of low-transparent(LT) ceramic blocks was significantly higher than that of other transparent ceramic blocks. A was the most frequently used ceramic color. The most frequently used porcelain blocks for veneers were LTA2 and LTA1; for inlay were LTA3; for crowns were LTA2 and LTA3. The blocks used in the fixed bridges were all LT, and A3 color was the majority. CONCLUSIONS: Chairside CAD/CAM all-ceramic prostheses made of IPS e.max CAD materials have been widely used in clinical practice. The types of prostheses include veneer, inset, crown and fixed bridge. The most commonly used IPS e.max CAD blocks are LTA2, LTA3 and LTA1. These findings have certain guiding significance for the clinical restoration decision and the reserve of porcelain blocks in primary hospitals.

Cerium doping of 45S5 bioactive glass improves redox potential and cellular bioactivity.

45S5 Bioglass (BG) is composed of a glass network with silicate based on the component and can be doped with various therapeutic ions for the enhancement of hard tissue therapy. Nanoceria (CeO2) has been shown to indicate redox reaction and enhance the biological response. However, few studies focus on the proportion of CeO2-doped and its effect on the cellular bioactivity of CeO2-doped BG (CBG). In this study, we synthesized the CBG series with increasing amounts of doping CeO2 ranging (1 to 12) wt.%. The synthesized CBG series examined the characterization, mineralization capacity, and cellular activity against BG. Our results showed that the CBG series exhibited a glass structure and indicated the redox states between Ce3+ and Ce4+, thus they showed the antioxidant activity by characterization of Ce. The CBG series had a stable glass network structure similar to BG, which showed the preservation of bioactivity by exhibiting mineralization on the surface. In terms of biological response, although the CBG series showed the proliferative activity of pre-osteoblastic cells similar to BG, the CBG series augmented not only the alkaline phosphatase activity but also the osteogenic marker in the mRNA level. As stimulated the osteogenic activity, the CBG series improved the biomineralization. In conclusion, the CBG series might have a potential application for hard tissue therapeutic purposes.

Employing novel biocompatible composite scaffolds with bioglass 58S and poly L-lactic acid for effective bone defect treatment.

BACKGROUND: Bioglass materials have gained significant attention in the field of tissue engineering due to their osteoinductive and biocompatible properties that promote bone cell differentiation. In this study, a novel composite scaffold was developed using a sol-gel technique to combine bioglass (BG) 58 S with a poly L-lactic acid (PLLA). METHODS AND RESULTS: The physiochemical properties, morphology, and osteoinductive potential of the scaffolds were investigated by X-ray diffraction analysis, scanning electron microscopy, and Fourier-transform infrared spectroscopy. The results showed that the SiO2-CaO-P2O5 system was successfully synthesized by the sol-gel method. The PLLA scaffolds containing BG was found to be osteoinductive and promoted mineralization, as demonstrated by calcium deposition assay, upregulation of alkaline phosphatase enzyme activity, and Alizarin red staining data. CONCLUSIONS: These in vitro studies suggest that composite scaffolds incorporating hBMSCs are a promising substitute material to be implemented in bone tissue engineering. The PLLA/BG scaffolds promote osteogenesis and support the differentiation of bone cells, such as osteoblasts, due to their osteoinductive properties.

Biocompatibility, bioactivity, porosity, and sealer/dentin interface of bioceramic ready-to-use sealers using a dentin-tube model.

This study evaluated the biocompatibility, bioactivity, porosity, and sealer/dentin interface of Sealer Plus BC (SP), Bio-C Sealer (BIOC), TotalFill BC Sealer (TF), and AH Plus (AHP). Dentin tubes filled with the sealers and empty tubes (control group) were implanted in the subcutaneous tissue of rats for different periods (n = 6 per group/period). Number of inflammatory cells (ICs), capsule thickness, von Kossa reaction, interleukin-6 (IL-6) and osteocalcin (OCN) were evaluated. Porosity and voids in the interface dentin/sealers were assessed by micro-computed tomography. The data were submitted to ANOVA/Tukey's tests (α = 0.05). Greater capsule thickness, ICs and IL-6 immunolabeling cells were observed in AHP. No significant difference in thickness of capsule, ICs, and IL-6- immunolabeling cells was detected between SP and TF, in all periods, and after 30 and 60 days between all groups. At 60 days all groups had reduction in capsule thickness, ICs and IL-6 immunolabeling cells. Von Kossa-positive and birefringent structures were observed in the capsules around the sealers. BIOC, SP, and TF exhibited OCN-immunolabeling cells. All sealers had porosity values below 5%, besides low and similar interface voids. BIOC, SP and TF are biocompatible, bioactive, and have low porosity and voids. The dentin-tube model used is an alternative for evaluating bioceramic materials.

Effect of different occlusal materials on peri-implant stress distribution with different osseointegration condition: A finite element analysis.

AIM: Studies have not been done to evaluate the peri-implant stress exerted by materials(like PEEK and resin matrix ceramics) in different osseointegration conditions. To investigate the effect of different occlusal materials on peri-implant stress distribution with different osseointegration condition using finite element analysis. SETTINGS AND DESIGN: Eighteen different 3D FEA models of implant fixed with abutment were created involving 6 different occlusal materials (Heat cured temporary acrylic resin (PMMA), Bis-GMA, PEEK, Lithium disilicate, Resin matrix ceramics and translucent Zirconia) and different osseointegrated conditions (50%, 75%, 100%). MATERIALS AND METHODS: Models were subjected to loading vertically and obliquely followed by evaluation of stress distribution. STATISTICAL ANALYSIS USED: The results of the simulation obtained were analysed in terms of Von mises, maximum principal and minimal principal stresses using descriptive stastistics. RESULTS: PMMA (40.14 MPa on vertical loading and 66 MPa on oblique loading) resulted in the highest stresses and lithium disilicate (24 MPa on vertical loading and 52.40 MPa on oblique loading) resulted in least stresses among all the crown materials. Upon oblique loading, von Mises stress increases except for translucent zirconia and lithium disilicate (52.444 MPa on 50%, 47.733 MPa on 75%, and 43.973 MPa on 100% osseointegration). Minimal principal stress values decreased with increase in osseointegration upon oblique loading for PMMA, BisGMA, and PEEK. CONCLUSION: Translucent zirconia and lithium disilicate offer a better stress transmission. Minimal principal stress values of PEEK and BisGMA decreased with increasing osseointegration.

Effect of conventional cigarette smoking and recent heated tobacco products on CAD/CAM restorative materials.

OBJECTIVE: To determine the effects of conventional cigarette smoking (CS) and recent heated tobacco products (HTPs) on the surface roughness and color stability of different indirect restorative materials. MATERIALS AND METHODS: One hundred disc-shaped samples were constructed of three different restorative CAD/CAM materials: lithium disilicate glass-ceramic (IPS e.max CAD; Ivoclar Vivadent, Liechtenstein), zirconia (BruxZir® Zirconia, Glidewell, USA) and polyetheretherketone (BioHPP® bredent GmbH, Germany). Of the IPS e.max CAD and the Bruxzir samples, 20 samples were glazed, and 20 samples were polished, while the BioHPP samples were all polished according to the manufacturer's instructions. Fifty samples were subjected to conventional cigarette smoking (LM, Philip Morris International Inc., Egypt) (Groups: IPS e.max CAD_Glazed exposed to CS (LD_G_Cig), IPS e.max CAD_Polished exposed to CS (LD_P_Cig), Bruxzir_Glazed exposed to CS (Zr_G_Cig), Bruxzir _Polished exposed to CS (Zr_P_Cig) and BioHPP exposed to CS (PEEK_Cig) and fifty samples were exposed to heated tobacco product smoking (Heets, Russet selection, Philip Morris International Inc., Italy) (Groups: IPS e.max CAD_Glazed exposed to HTP (LD_G_HTP), IPS e.max CAD_Polished exposed to HTP (LD_P_HTP), Bruxzir_Glazed exposed to HTP (Zr_G_HTP), Bruxzir CAD_Polished exposed to HTP (Zr_P_HTP) and BioHPP exposed to HTP (PEEK_HTP).. Six hundred cigarettes/heets representing 30 days of medium smoking behavior (20 cigarettes/day) were used. Before and after exposure to smoke, the surface roughness of all the samples was measured using JITAI8101 surface roughness tester (Beijing Jitai Tech Detection Device Co., Ltd, China, and the color parameters were assessed using VITA Easyshade Advance 4.01 (VITA shade, VITA made, VITA). The data were analyzed using One-way ANOVA, paired sample t-test and independent sample t-test. The significance level was set at α < 0.05. The surface topography was evaluated by scanning electron microscopy (SEM) and analyzed using energy-dispersive X-ray (EDX) spectroscopy to determine changes in the surface chemical composition. RESULTS: Both types of smoking caused significant increases in the surface roughness of all the samples. There was a significant difference in color change between CS and HTP for all materials with different surface finish (P < 0.01) and zirconia had the greatest effect on color change (P < 0.001). In contrast, polyetheretherketone (PEEK) "BioHPP" had the least effect (P < 0.001). CONCLUSION: Exposure to different types of smoking induce changes in the surface topography and color of different esthetic restorative materials. Compared with HTP, conventional cigarette smoke has a greater effect on the surface roughness and color stability of esthetic restorative materials. The glazed surfaces showed less change in surface topography than did the polished surfaces. Zirconia showed better color stability when compared to polyetheretherketone (PEEK).

Effect of Coffee Thermocycling on Color Stability and Translucency of CAD-CAM Polychromatic High Translucent Zirconia Compared With Lithium Disilicate Glass Ceramic.

AIMS AND OBJECTIVES: To evaluate the effect of coffee thermocycling on color stability and translucency of CAD-CAM polychromatic high translucent zirconia compared with lithium disilicate glass ceramic. METHODS: Sixteen rectangular plates (14 × 16 × 1.0 mm) of two ceramic materials (IPS E.max CAD (IEC), IPS E.max ZirCAD Prime [IZP]) were prepared. Each specimen was measured for color coordinates using a spectrophotometer following 30,000 cycles of coffee thermocycling. CIELAB formula was used to determine color and translucency differences (ΔE and ΔTP). The means of ΔE and ΔTP were compared using independent samples t-test and were evaluated using their respective 50%:50% perceptibility and acceptability thresholds (PT and AT). One-way analysis of variance was performed to evaluate the translucency parameter (TP) and surface roughness (Ra) of each material. RESULTS: Mean ΔE values of IEC (4.69) and IZP (4.64) were higher than the AT (ΔE ≤ 2.7) with no significant difference found between the two groups (p = 0.202). Considering the TP, only IEC showed a statistically significant increase in TP value (p < 0.001). However, the mean ΔTP of IEC (3.25) remained within the range of acceptability (1.3 < ΔTP ≤ 4.4). CONCLUSIONS: Within the limitations of this current study, the color stability of all materials was clinically affected by coffee thermocycling. In terms of translucency, only lithium disilicate glass ceramic was influenced by coffee thermocycling. High translucent zirconia had superior translucency stability compared to lithium disilicate glass ceramic.

Effects of Different Concentrations of Carbamide Peroxide on Color, Surface Roughness, and Hardness of CAD/CAM Dental Ceramics.

OBJECTIVES: This study assessed the effects of 15% and 20% carbamide peroxide (CP) on color, surface roughness, and hardness of computer-aided design/computer-aided manufacturing (CAD/CAM) dental ceramics. MATERIALS AND METHODS: This in vitro study was conducted on 120 Vita Mark II, Celtra Duo, and Suprinity CAD/CAM ceramic specimens. The ceramic specimens in each group (n = 40) were randomly assigned to two subgroups (n = 20) for polishing and glazing, and their baseline color, surface roughness (Ra), and hardness were assessed. In each subgroup, half of the specimens were exposed to 15% CP, while the other half were exposed to 20% CP. Their color change (ΔE), surface roughness, and hardness were then measured again. Surface roughness, hardness, and color were analyzed sequentially by profilometer, Vickers hardness tester, and spectrophotometer, respectively. Data were analyzed by repeated measures ANOVA, one-way ANOVA, and post hoc Bonferroni test (α = 0.05). RESULTS: The surface roughness of all groups significantly increased after bleaching treatment (p < 0.05). Surface hardness of all groups decreased after bleaching treatment, but this reduction was only significant in Vita Mark II subgroups (glazed, polished, 15%, and 20% CP). The ΔE was not clinically and visually perceivable in any group. CONCLUSION: The present results revealed that concentration of CP and type of surface treatment affected the surface properties of CAD/CAM ceramics. Type of surface treatment only affected the surface hardness of Vita Mark II ceramics (p < 0.05). Concentration of CP had a significant effect only on polished Vita Mark II.

Development of Bioactive Hybrid Poly(lactic acid)/Poly(methyl methacrylate) (PLA/PMMA) Electrospun Fibers Functionalized with Bioglass Nanoparticles for Bone Tissue Engineering Applications.

Hybrid scaffolds that are based on PLA and PLA/PMMA with 75/25, 50/50, and 25/75 weight ratios and functionalized with 10 wt.% of bioglass nanoparticles (n-BG) were developed using an electrospinning technique with a chloroform/dimethylformamide mixture in a 9:1 ratio for bone tissue engineering applications. Neat PLA and PLA/PMMA hybrid scaffolds were developed successfully through a (CF/DMF) solvent system, obtaining a random fiber deposition that generated a porous structure with pore interconnectivity. However, with the solvent system used, it was not possible to generate fibers in the case of the neat PMMA sample. With the increase in the amount of PMMA in PLA/PMMA ratios, the fiber diameter of hybrid scaffolds decreases, and the defects (beads) in the fiber structure increase; these beads are associated with a nanoparticle agglomeration, that could be related to a low interaction between n-BG and the polymer matrix. The Young's modulus of PLA/PMMA/n-BG decreases by 34 and 80%, indicating more flexible behavior compared to neat PLA. The PLA/PMMA/n-BG scaffolds showed a bioactive property related to the presence of hydroxyapatite crystals in the fiber surface after 28 days of immersion in a Simulated Body Fluids solution (SBF). In addition, the hydrolytic degradation process of PLA/PMMA/n-BG, analyzed after 35 days of immersion in a phosphate-buffered saline solution (PBS), was less than that of the pure PLA. The in vitro analysis using an HBOF-1.19 cell line indicated that the PLA/PMMA/n-BG scaffold showed good cell viability and was able to promote cell proliferation after 7 days. On the other hand, the in vivo biocompatibility evaluated via a subdermal model in BALC male mice corroborated the good behavior of the scaffolds in avoiding the generation of a cytotoxic effect and being able to enhance the healing process, suggesting that the materials are suitable for potential applications in tissue engineering.

Tailoring zirconia surface topography via femtosecond laser-induced nanoscale features: effects on osteoblast cells and antibacterial properties.

The performance and long-term durability of dental implants hinge on the quality of bone integration and their resistance to bacteria. This research aims to introduce a surface modification strategy for zirconia implants utilizing femtosecond laser ablation techniques, exploring their impact on osteoblast cell behavior and bacterial performance, as well as the integral factors influencing the soft tissue quality surrounding dental implants. Ultrafast lasers were employed to craft nanoscale groove geometries on zirconia surfaces, with thorough analyses conducted using x-ray diffraction, scanning electron microscopy, atomic force microscopy, and water contact angle measurements. The study evaluated the response of human fetal osteoblastic cell lines to textured zirconia ceramics by assessing alkaline phosphatase activity, collagen I, and interleukin 1ßsecretion over a 7 day period. Additionally, the antibacterial behavior of the textured surfaces was investigated usingFusobacterium nucleatum, a common culprit in infections associated with dental implants. Ciprofloxacin (CIP), a widely used antibacterial antibiotic, was loaded onto zirconia ceramic surfaces. The results of this study unveiled a substantial reduction in bacterial adhesion on textured zirconia surfaces. The fine biocompatibility of these surfaces was confirmed through the MTT assay and observations of cell morphology. Moreover, the human fetal osteoblastic cell line exhibited extensive spreading and secreted elevated levels of collagen I and interleukin 1ßin the modified samples. Drug release evaluations demonstrated sustained CIP release through a diffusion mechanism, showcasing excellent antibacterial activity against pathogenic bacteria, includingStreptococcus mutans, Pseudomonas aeruginosa, andEscherichia coli.

Gamma-ray shielding characteristics of concrete containing different percentage of ceramics for different energies.

To shield people from dangerous gamma radiation, it is imperative to fabricate inexpensive and environmentally friendly materials. In the present work, suitability of concrete with various % concentrations of ceramics as gamma-ray shielding material has been studied. In this regard, concrete mixture using M-sand and cement with ceramic as filler in different concentrations has been prepared. The mass attenuation coefficients of the prepared samples were measured for different concentrations of ceramics such as 15, 30, 45 and 60%. The mass attenuation coefficients, half value layer (HVL) and tenth vale layer (TVL) of the prepared samples were determined using gamma-ray spectrometer with NaI(Tl) detector at 511, 661.6, 1173, 1332 keV gamma energies. Experimentally obtained mass attenuation coefficients varied from 0.080 to 0.090, 0.074 to 0.086, 0.056 to 0.072 and 0.054 to 0.055 cm2 g-1 at 511, 662, 1173 and 1332 keV, respectively. Therefore concrete mixture with ceramics filler could be a promising shielding material than the bare concrete.

Marginal integrity of prototype bioactive glass-doped resin composites in class II cavities.

OBJECTIVES: This in vitro study examined the marginal integrity of experimental composite materials doped with bioactive glass (BG). MATERIALS AND METHODS: Class-II MOD cavities were prepared and restored with one of the following composite materials: a commercial composite material as a reference (Filtek Supreme XTE), an experimental composite doped with BG 45S5 (C-20), and an experimental composite doped with a fluoride-containing BG (F-20). Six experimental groups (n = 8) were used, as each of the three composites was applied with (+) or without (-) a universal adhesive (Adper Scotchbond Multipurpose). All specimens were subjected to thermocycling (10,000 x, 5-55 °C) and then additionally stored in artificial saliva for eight weeks. Scanning electron micrographs of the mesial and the distal box were taken at three time points (initial, after thermocycling, and after eight weeks of storage in artificial saliva). The margins were classified as "continuous" and "non-continuous" and the percentage of continuous margins (PCM) was statistically analyzed (α = 0.05). RESULTS: In most experimental groups, thermocycling led to a significant decrease in PCM, while the additional 8-week aging had no significant effect. F-20 + performed significantly better (p = 0.005) after 8 weeks storage in artificial saliva than the reference material with adhesive, while no statistically significant differences were observed at the other two time points. C-20 + exhibited significantly better PCM than the reference material with adhesive after thermocycling (p = 0.026) and after 8 weeks (p = 0.003). CONCLUSIONS: Overall, the experimental composites with BG showed at least as good marginal adaptation as the commercial reference, with an indication of possible re-sealing of marginal gaps. CLINICAL RELEVANCE: Maintaining or improving the marginal integrity of composite restorations is important to prevent microleakage and its likely consequences such as pulp irritation and secondary caries.

Methodological approaches in graded dental ceramics: a scoping review protocol.

OBJECTIVES: This review will map the various methodological approaches used in graded dental ceramics and distinguish their material characteristics and properties. The aim is to identify gaps in the development and application of grading in dental ceramic systems. INTRODUCTION: The advantage of functionally graded materials is the absence of the weakest link, with no distinct boundaries, thereby eliminating the possibility of stress concentrations at the interfaces. Functionally graded materials are well established in nature, such as in human teeth, bone, and the bio-tissues of plants and animals. This concept has also been explored in dental ceramics to enhance fatigue resistance and strength. INCLUSION CRITERIA: This review will include observational studies and interventional studies, such as in vitro and experimental studies, on functionally graded dental ceramic systems. Studies that use finite element analysis to evaluate stress distributions, and studies on the mechanical performance of graded dental ceramics, irrespective of the type of ceramic material, design, or thickness of graded layers, will be considered. METHOD: The review will follow the JBI methodology for scoping reviews and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews. MEDLINE (PubMed), Scopus, ProQuest Dissertations and Theses (EBSCOhost), Cochrane CENTRAL, and Google Scholar will be searched for English language studies. The search strategy will be based on MeSH terms and free-text specific terms, and will be adapted for each database. Two independent reviewers will screen titles and abstracts, and extract data from selected sources. The data extracted from the selected studies will be analyzed and presented in the form of tables and figures. REVIEW REGISTRATION: Open Science Framework: https://osf.io/ahsp7.

Purification of Adeno-Associated Viral Vector Serotype 9 Using Ceramic Hydroxyapatite Chromatography and its Analysis.

Adeno-associated virus (AAV) vectors can efficiently transduce exogenous genes into various tissues in vivo. Owing to their convenience, high efficiency, long-term stable gene expression, and minimal side effects, AAV vectors have become one of the gold standards for investigating gene functions in vivo, especially in non-clinical studies. However, challenges persist in efficiently preparing a substantial quantity of high-quality AAV vectors. Commercial AAV vectors are typically associated with high costs. Further, in-laboratory production is hindered by the lack of specific laboratory equipment, such as ultracentrifuges. Therefore, a simple, quick, and scalable preparation method for AAV vectors is needed for proof-of-concept experiments. Herein, we present an optimized method for producing and purifying high-quality AAV serotype 9 (AAV9) vectors using standard laboratory equipment and chromatography. Using ceramic hydroxyapatite as a mixed-mode chromatography medium can markedly increase the quality of purified AAV vectors. Basic Protocols and optional methods for evaluating purified AAV vectors are also described. © 2024 The Author(s). Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Production of AAV9 vectors in 293EB cells Basic Protocol 2: Concentration and buffer exchange of AAV9 vectors from 293EB cell culture supernatants using tangential flow filtration Basic Protocol 3: Purification of AAV9 vectors from TFF samples using ceramic hydroxyapatite chromatography Basic Protocol 4: Analysis of the purified AAV9 vectors.

Effect of different design and surface treatment on the load-to-failure of ceramic repaired with composite.

Glass ceramics are widely used to manufacture esthetic veneers, inlays, onlays, and crowns. Although the clinical survival rates ofglass-ceramic restorations arefavorable,fractures or chips are common. Certain cases can be repaired with direct composite. AIM: The aim of this study was to investigate the interaction effect of different designs and surface treatments on the load-to-failure of lithium disilicate glass-ceramic repaired with nanofilled composite. MATERIALS AND METHOD: Lithium-disilicate glass-ceramic slabs (IPS e.max Press, Ivoclar Vivadent) with three different designs of the top surface (flat, single plateau, or doubleplateau) (n=U) received 'no treatment', '5% HF etching', or "AI2O3 sandblasting". HF-etched and sandblasted slabs also received silane and universal one-step adhesive application. All slabs were incrementally repaired with nanofilled composite (Filtek Z350, 3M ESPE) up to6 mm above the highest ceramic top plateau. Specimens were stored in artificial saliva at 37 °C for 21 days and then subjected to 1,000 thermocycles between 5 and 55 °C. The interface composite-ceramic of each specimen was tensile tested until failure in a universal testing machine and the mode of failure was determined under a stereomicroscope. The ceramic surface morphology of one representative tested specimen from each subgroup (design/surface treatment) was observed through scanning electron microscopy (SEM). RESULTS: Regardless of ceramic design, the absence of surface treatment resulted in significantly lower load-to-failure values. No significant differences in load-to-failure values were observed between HF-etched and sandblasted specimens for the flat design; however, HF etching resulted in significantly higher load-to-failure values than sandblasting for both single plateau and double plateau designs. The majority (60%) of HF-etched specimens with single plateau or double plateau presented mixed failures. SEM photomicrographs showed that HF-etched specimens had smoother surfaces than sandblasted specimens. CONCLUSION: The surface treatment of a defective lithium disilicate glass-ceramic restoration has more influence than its macroscopic design on the retention of the composite repair. HF etching seems to provide higher bond strength to the composite repair.

Embora fraturas e lascamento de restauragoes vitrocerámicas sejam comuns, alguns casos podem ser reparados com compósito direto. OBJETIVO: investigar o efeito da interagao de diferentes formas e tratamentos de superficie na carga de ruptura de uma vitrocerámica reforgada com dissilicato de litio reparada com compósito nanoparticulado. MATERIAIS E MÉTODOS: A superficie superior de espécimes de vitroceramica (IPS e.max Press, Ivoclar Vivadent) foi preparada com tres formas (plana, plato único, ou duplo) e recebeu (n=11): 'nenhum tratamento', 'condicionamento com ácido hidrofluoridrico 5%', ou 'jateamento com AfOf. Ambos espécimes condicionados e jateados receberam silano e adesivo universal. Todos os espécimes foram reparados incrementalmente com compósito (Filtek Z350, 3M ESPE) até6 mm acima do plato cerámico mais alto, armazenados em saliva artificial á 37 °C por 21 dias, e submetidos á 1.000 termociclos (5 e 55 °C). A interface compósito-cerámica de cada amostra foi testada á tragao até sua falha em máquina universal e o modo de falha foi determinado com estereomicroscópio. A morfologia da superficie de uma amostra representativa de forma/tratamento de superficie foi observada através de microscopia eletronica de varredura (MEV). RESULTADOS: Independentemente da forma ceramica, a ausencia de tratamento superficial resultou em valores de carga de ruptura significativamente menores. Nao foi observada differenga significativa entre os espécimes planos condicionados ou jateados; no entanto, o condicionamento resultou em valores significativamente maiores que o jateamento para espécimes com plato único e duplo. A maioria (60%) dos espécimes condicionados e com plato único ou duplo apresentou falhas mistas. Imagens SEM demonstraram rugosidade superficial mais regular dos espécimes condicionados que os jateados. CONCLUSÕES: O tratamento superficial de uma restauragao defeituosa de vitrocerámica reforgada por dissilicato de litio tem maior influencia na retengao do reparo de compósito do que sua forma macroscópica; ainda, o condicionamento com ácido hidrofluoridrico parece proporcionar maior resistencia de uniao ao reparo com compósito.

Composite bone graft of CaO-MgO-SiO2 glass-ceramics and CaSO4 ceramics for boosting bone formation rate.

This study develops a composite bone graft of CaO-MgO-SiO2 glass-ceramic and CaSO4 [abbreviated as (CMS)3-x(CS)x] via the sponge replication technique with weight fractions of x = 0, 1, 1.5, 2, and 3. The (CMS)1.5(CS)1.5 composite displays a superior degradability and, a suitable compressive strength of ∼3 MPa, and excellent cell proliferation and differentiation. The in vivo rat femur test in the hybrid-pore (CMS)1.5(CS)1.5 composite granules achieves a higher rate of bone formation, which is ∼2.7 times better than that of the commercial HAP/ß-TCP at 12 weeks. Improved expressions of osteocyte and mature osteocyte marker genes, namely (Spp1, Dmp1, and Fgf23), were observed in the (CMS)1.5(CS)1.5 group, indicating a faster differentiation into mature bone tissue. The ions release of (CMS)1.5(CS)1.5 through the ERK1/2 signaling pathway promotes osteogenic differentiation. The high bone generation rate can be attributed to faster active ions release and modified surface topography. This work highlights an excellent bone graft candidate for clinical applications in orthopedic surgery.

The influence of hygroscopic expansion of resin supporting dies on the fracture resistance of ceramic restorations during thermal cycling.

OBJECTIVES: To evaluate the hygroscopic expansion characterization of resin composite dies during thermal cycling, and their influence on the fracture resistance of dental ceramic materials as well as the effect of pre-immersion on these measurements. METHODS: Disc-shaped specimens (φ = 15.0 mm, h = 1.2 mm) and anatomical crown dies of four resin composites (epoxy, Z350, P60, G10) were fabricated. Disc-shaped samples were continuously soaked in distilled water and the volume expansion was measured at different time point by Archimedes method. Disc-shaped samples were pre-immersed for 0, 7, or 30 days, elastic modulus and hardness were measured using Nanoindentation test; thermal cycling (TC) test was performed (5 °C-55 °C, 104 cycles), and volume expansion during TC was measured. Four kinds of resin die with pre-immersion for 0, 7, or 30 days were cemented to 5Y-Z crown, or epoxy dies without pre-immersion were cemented to 5Y-Z, 3Y-Z and lithium disilicate glass (LDG) crowns, and load-to-failure testing was performed before and after TC. Finite element analysis (FEA) and fractography analysis were also conducted. RESULTS: The hygroscopic expansion was in the order: epoxy > Z350 > P60 > G10. Except for G10, the other three resin composites exhibited different degrees of hygroscopic expansion during TC. Only the elastic modulus and hardness of epoxy decreased after water storage. However, only the fracture loads of 5Y-Z and LDG crowns supported by epoxy dies were significantly decreased after TC. FEA showed a stress concentration at the cervical region of the crown after volume expansion of the die, leading to the increase of the peak stress at the crown during loading. SIGNIFICANCE: Only the hygroscopic expansion of epoxy dies caused by TC led to the decrease in the fracture resistance of the 5Y-Z and LDG crown, which may be related to the decrease in the elastic modulus of the epoxy die and the tensile stress caused by it.

Ceramic conversion treated titanium implant abutments with gold for enhanced antimicrobial activity.

INTRODUCTION: Peri-implantitis is an inflammatory process around dental implants that is characterised by bone loss that may jeopardize the long-term survival of osseo integrated dental implants. The aim of this study was to create a surface coating on titanium abutments that possesses cellular adhesion and anti-microbial properties as a post-implant placement strategy for patients at risk of peri-implantitis. MATERIALS AND METHODSMETHODS: Titanium alloy Grade V stubs were coated with gold particles and then subjected to ceramic conversion treatment (CCT) at 620 °C for 3, 8 and 80 h. The surface characteristics and chemistry were assessed using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) analysis. The leaching profile was investigated by inductively coupled plasma mass spectroscopy (ICP-MS) for all groups after 7, 14 and 28 days in contact with distilled water. A scratch test was conducted to assess the adhesion of the gold coating to the underlying titanium discs. Two bacterial species (Staphylococcus aureus (SA) & Fusobacterium nucleatum (FN)) were used to assess the antibacterial behaviour of the coated discs using a direct attachment assay test. The potential changes in surface chemistry by the bacterial species were investigated by grazing angle XRD. RESULTS: The gold pre-coated titanium discs exhibited good stability of the coating especially after immersion in distilled water and after bacterial colonisation as evident by XRD analysis. Good surface adhesion of the coating was demonstrated for gold treated discs after scratch test analysis, especially titanium, following a 3-hour (3 H) ceramic conversion treatment. All coated discs exhibited significantly improved antimicrobial properties against both tested bacterial species compared to untreated titanium discs. CONCLUSIONS: Ceramic conversion treated titanium with a pre-deposited gold layer showed improved antimicrobial properties against both SA and FN species than untreated Ti-C discs. Scratch test analysis showed good adherence properties of the coated discs the oxide layer formed is firmly adherent to the underlying titanium substrate, suggesting that this approach may have clinical efficacy for coating implant abutments.

Advances in zirconia-based dental materials: Properties, classification, applications, and future prospects.

OBJECTIVES: Zirconia (ZrO2) ceramics are widely used in dental restorations due to their superior mechanical properties, durability, and ever-improving translucency. This review aims to explore the properties, classification, applications, and recent advancements of zirconia-based dental materials, highlighting their potential to revolutionize dental restoration techniques. STUDY SELECTION, DATA AND SOURCES: The most recent literature available in scientific databases (PubMed and Web of Science) reporting advances of zirconia-based materials within the dental field is thoroughly examined and summarized, covering the major keywords "dental zirconia, classification, aesthetic, LTD, applications, manufacturing, surface treatments". CONCLUSIONS: An exhaustive overview of the properties, classifications, and applications of dental zirconia was presented, alongside an exploration of future prospects and potential advances. This review highlighted the importance of addressing challenges such as low-temperature degradation resistance and optimizing the balance between mechanical strength and translucency. Also, innovative approaches to improve the performances of zirconia as dental material was discussed. CLINICAL SIGNIFICANCE: This review provides a better understanding of zirconia-based dental biomaterials for dentists, helping them to make better choice when choosing a specific material to fabricate the restorations or to place the implant. Moreover, new generations of zirconia are still expected to make progress on key issues such as the long-term applications in dental materials while maintaining both damage resistance and aesthetic appeal, defining the directions for future research.

Quantitative examination of factors influencing the colour reproduction ability of lithium disilicate glass-ceramics.

BACKGROUND: Effects of ceramic translucency, layer thickness, and substrate colour on the shade of lithium disilicate glass-ceramic restorations proved to be significant in several studies, however, quantitative, numerical results on the relationship between the colour difference and these parameters are still lacking. The purpose of this in vitro study was to quantitatively determine how the colour reproduction ability of a lithium disilicate glass-ceramic is affected by its translucency, layer thickness, and substrate colour. METHODS: Ceramic samples were prepared from A2 shade IPS e.max CAD blocks with high and low translucencies (HT and LT) in a thickness range of 0.5-2.5 mm (+/- 0.05 mm). Layered samples were acquired utilizing composite substrates in 9 shades; transparent try-in paste was used. The spectral reflectance of the specimens was assessed under D65 standard illumination with a Konica Minolta CM-3720d spectrophotometer. The CIEDE2000 colour difference (ΔE00) between two samples was analysed using perceptibility and acceptability thresholds set at 50:50%. Statistical analysis involved linear regression analysis and the Kruskal-Wallis test. RESULTS: An increase in the thickness of 0.5 mm reduced the ΔE00 of the HT samples to 72.8%, and that of the T samples to 71.1% (p < 0.0001). 7 substrates with HT and LT specimens had significantly different results from the mean (p < 0.05). A thickness of 0.5 mm is not sufficient to achieve an acceptable result at any level of translucency, while the low translucency ceramic at a thickness of 1.5 mm gave acceptable results, except for severely discoloured substrates (ND8 and ND9). CONCLUSIONS: The colour reproduction ability of lithium disilicate glass-ceramics is significantly affected by their translucency, layer thickness, and 7 substrates out of 9 substrates examined.