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The purpose of this study is to present current dental ceramic materials and processing methods. The clinical indication was emphasized on basis of the material's microstructure and composition. Studies of ceramic characterization were also discussed, as they impact the clinical indication and serve as a parameter for the development of new materials. The novel strategies were mostly found aiming to mimic the natural dental structures, provide mechanical reliability, and develop predictable restorations in terms of adaptation and design.

This systematic review was performed to determine the main cause of technical failure of tooth-supported zirconia crowns and fixed partial dentures (FPDs), categorizing them as fracture/chipping or loss of retention/decementation.Electronic and manual searches were performed for randomized clinical trials, prospective clinical trials, and prospective cohort studies that reported the technical failure rates of zirconia restorations. The Cochrane Collaboration risk-of-bias tool and Newcastle-Ottawa scale were used to assess the quality of the studies.Fifty-two studies were included and most of them had unclear risk of bias. Considering all reported fractures/chipping, for veneered crowns with 1 to 3 years of follow-up, the relative risk (RR) of fracture in relation to loss or retention was 3.95 (95% CI 1.18-13.23; p = 0.03). For 4 to 6 years of follow-up, the RR was 5.44 (95% CI 1.41-20.92; p = 0.01). For veneered FPDs with 1 to 3 years of follow-up, the RR was 5.98 (95% CI 2.31-15.01; p = 0.0002). For 4 to 6 years of follow-up, the RR was 3.70 (95% CI 1.63-8.41; p = 0.002). For 7 years or more of follow-up, the RR was 3.45 (95% CI 1.84-6.46; p = 0.0001). When only framework fractures were considered, there were no significant differences for the RR in all follow-up periods (p 0.05).Higher RR for fracture/chipping in relation to decementation for veneered zirconia crowns and FPDs at all follow-up times. For framework fractures, no difference was observed between the risk of failure of the restoration due to fracture or decementation.Zirconia crowns and FPDs showed relatively high success and survival rates. However, considering the technical failures, there is approximately four times higher chance of fracture/chipping than loss of retention for both single and multi-unit tooth-supported veneered zirconia restorations.

To evaluate the force absorption capacity of implant supported restorations utilizing different CAD-CAM materials for the fabrication of crowns and customized abutments.80 titanium inserts were scanned to design customized abutments and crowns. The specimens were divided into four groups (n = 20/material): (Z): zirconia, (P): PEEK, (V): VITA Enamic, and (E): IPS e.max. Each group was subdivided into two subgroups according to customized abutment material: (Z) zirconia, and (P) for PEEK. For the assessment of force absorption, all specimens were loaded in a universal testing machine, applied loads curves were collected from the machine's software, and resulting loads curves were collected from forcemeter below the assembly. The slopes of all curves were analyzed using Two-way multivariate analysis of variance with pairwise comparisons using Tukey Post Hoc test (p 0.05).The curve progression of the applied and resulting forces varied among the investigated materials for each specimen. For zirconia abutments, ZZ showed the highest slope values of the applied and resulting force curves, followed by EZ, VZ, and PZ demonstrating statistically significant differences (P .001). As for PEEK abutments, ZP and EP showed the least slope values, followed by PP then VP demonstrating statistically significant differences (P .001). For Zirconia and e.max crowns, using PEEK abutments significantly increased slope loss. As for PEEK and Vita Enamic crowns changing abutment material did not significantly affect slope loss.Combining rigid crown materials with less rigid abutments might enhance their force absorption capacity. However, with less rigid crown materials a stiff substructure might be mandatory to preserve their force absorption behavior.

Distance between dentistry and medicine is a traditional and historical obstacle that affects multiple levels of the health system, especially the health policies to improve health service quality. Changes in dental education, especially involving the adoption of integrative health models in professional development, are considered essential for reducing this gap. We aimed to show a dental curriculum focused on special care as a tool for medicine-dentistry integration.In this study, we present a new proposal for an undergraduate dental curriculum in which topics related to special care are addressed transversally and are the core for interdisciplinary integration of oral health with systemic health. We also describe how themes related to dental home care and hospital dentistry were included in this course as basic professional competencies.This initiative is aligned with the global trend to adopt educational systems that contribute to the reduction of health care inequalities and improve health service quality.

Um dos assuntos mais frequentes nas rodas de conversas de clínicos e pesquisadores é a forma como os profissionais da área da Odontologia utilizam as redes sociais. Na minha percepção, apesar de a maioria dos profissionais seguir as redes sociais e acompanhar o que os colegas estão publicando, seus comentários são, muitas vezes, negativos, como, por exemplo: “Você viu que fulano virou ‘blogueirinho’?” ou “Para fazer isso, ciclano deve estar desesperado para angariar pacientes para sua clínica ou alunos para seus cursos”, ou, ainda, “A minha geração era muito melhor, pois a gente não se expunha dessa forma”.

To characterize the physicomechanical properties of an alumina-toughened zirconia (ATZ). ATZ synthesis consisted of the addition of alumina particles in an yttria-stabilized tetragonal zirconia polycrystals (3Y-TZP) matrix. Specimens were obtained by uniaxial and isostatic pressing ATZ and 3Y-TZP powders and sintering at 1600°C/1 h and 1550°C/1 h, respectively. Crystalline content and residual stress were evaluated using X-ray diffraction (XRD). Microstructure was characterized by scanning electron microscopy (SEM). Optical properties were determined by reflectance test. Mechanical properties were assessed by biaxial flexural strength test. All analyses were performed before and after aging (134°C, 20 h, 2 bar). XRD and SEM revealed a typical ATZ and 3Y-TZP crystalline content, chiefly tetragonal phase, with a dense polycrystalline matrix, though a smaller grain size for ATZ. Aging triggered a similar monoclinic transformation for both systems; however, ATZ exhibited higher residual compressive stresses than 3Y-TZP. While as-processed 3Y-TZP demonstrated significantly higher characteristic strength relative to ATZ, no significant difference was observed after aging (~215 MPa increase in the ATZ strength). ATZ presented significantly higher opacity relative to 3Y-TZP, although aging significantly increased the translucency of both systems (increase difference significantly higher in the 3Y-TZP compared to ATZ). ATZ physicomechanical properties support its applicability in the dental field, with a lower detrimental effect of aging relative to 3Y-TZP.

To evaluate the effect of Er:YAG laser conditioning of a glass-infiltrated alumina-based zirconia-reinforced ceramic on its flexural strength and on bonding to a resin cement. Sixteen blocks (5 × 5 × 4 mm) and 50 discs (Ø 12 mm, 1 mm thickness) of In-Ceram Zirconia (ICZ) obtained from CAD-CAM blocks were infiltrated with glass. For the microtensile bond strength (μTBS) test, all blocks were treated with aluminum oxide (AOX) and divided into 4 groups (n = 4): G1 (AOX), no combined surface treatment; G2 (ROC), tribochemical silica-coating; G3 (EY200), Er:YAG laser 200 mJ/15 Hz; and G4 (EY250), Er:YAG laser 250 mJ/10 Hz. The ceramic blocks were silanated and cemented with a resin cement (Panavia F2.0/Kuraray) to composite resin blocks and subjected to the μTBS test. For the flexural strength evaluation, the discs were divided into 5 groups (n = 10) as described above, in addition to a control group (G5 - CTRL, mirror-polished without further treatment). Each surface treatment was submitted to qualitative evaluation under SEM. One-way ANOVA (α = 5%) revealed the highest bond strength value for EY200 with no significant difference from ROC. The groups AOX and EY250 showed similar μTBS values that were statistically lower than those of EY200. For flexural strength, ROC was the only group with significantly lower values when compared with the CTRL. The use of Er:YAG laser at 200 mJ/15 Hz can be considered an innovative and effective alternative for surface conditioning of ICZ since it did not reduce the flexural strength of the ceramic and improved the resin cement bond to this substrate.

This review aimed to illustrate the utility of additive manufacturing technologies for the fabrication of polymer, metal, and ceramic components within the confines of their current and potential clinical applications in dentistry. The literature reviewed on five additive manufacturing technologies, namely, vat-polymerization, material jetting, material extrusion, powder-based fusion, and binder jetting, have been investigated in relevance to their dental applications. These technologies have the following existing or potential clinical applications: diagnostic and definitive casts, custom trays, positioning guides for custom abutments, tooth preparation guides, interim dental restorations, all-ceramic crowns, metal crowns and copings, silicone indices, occlusal devices, complete dentures, wax patterns for intra- and extra-coronal restorations, surgical guides, removable partial dentures, and tooth- or implant-supported frameworks. Vat-polymerization, material jetting, and powder-based fusion technologies have existing clinical applications utilizing mainly polymers and metals. Additive manufacturing technologies need further development to be used with ceramic materials for dental applications.

Objective The aims of this study were: 1) to evaluate the effect of sintering temperature on microstructure, density and flexural strength of a 3Y-TZP/TiO2 composite containing 12.5 wt% of TiO2 compared to 3Y-TZP specimens (control); 2) to compare 3Y-TZP with the experimental 3Y-TZP/TiO2 composite, both sintered at 1400 °C, with respect to the following parameters: optical properties, characteristic strength, Weibull modulus, fatigue behavior, induction of osteoblasts proliferation and differentiation (mineralization nodules formation). Methods The 3Y-TZP and 3Y-TZP/TiO2 powders were uniaxially pressed and sintered at 1200 °C, 1300 °C, 1400 °C or 1500 °C for one hour in a furnace. The microstructural analysis consisted of X-ray diffraction and scanning electron microscopy. The density was measured by the Archimedes' principle and the flexural strength was obtained by the biaxial flexure test. The optical properties were measured using a spectrophotometer operating in the visible light wavelength range. The step-stress accelerated life testing was performed by the pneumatic mechanical cycler and the biological behavior achieved by using osteoblast-like cells (Osteo-1 cell line). Results Tetragonal zirconia was identified in all groups and cubic zirconia was identified only at 3Y-TZP group. The addition of TiO2 decreased the values of density and flexural strength of the composite 3Y-TZP/TiO2 in relation to 3Y-TZP regardless of the sintering temperature. The color difference between the two materials was not significant regarding L*a*b* parameters. The composite showed higher probability of failure, and induced higher proliferation and differentiation than control. Significance The composite developed have good aesthetic and biologics properties. However, its microstructure and mechanical properties need to be improved for future dental implant applications.

This study aimed to analyze the effects of polyvinyl chloride (PVC) film and oxygen-blocking gel (OBG) on the irradiance from an LED source and the depth of cure of a composite resin. Irradiance was measured with a curing radiometer, and curing depth was evaluated according to the methods described by the International Organization for Standardization (ISO 4049). Twelve experimental conditions were investigated in a 3 × 4 factorial design (n = 5 specimens per condition): no PVC film at the tip of the device, fitted PVC film, or misfit PVC film; and no OBG or a 1-, 2-, or 3-mm-thick layer of OBG. The data were analyzed using analysis of variance and Tukey tests (P0.05), and a linear regression test was performed between the variables (P0.05). The analyses showed that the variables under study influenced the irradiance (P0.05) but not the curing depth (P0.05). The 3 groups that did not have the PVC film and either did not have the OBG or had the OBG in a thickness of 1 or 2 mm were not significantly different from each other (P0.05) but presented the highest irradiance values among all the groups (P0.05). The use of the misfit PVC film with a 3-mm layer of OBG led to the lowest irradiance values (P0.05). The variables did not influence each other (P0.05). The results of this study indicated that the presence of PVC film, especially misfit film, reduced the irradiance. In addition, the greater the thickness of the OBG, the lower the irradiance. None of the PVC film barrier conditions or OBG thicknesses had an effect on the depth of cure.

Purpose This study aims to evaluate the effect of erosive, abrasive, and erosive/abrasive challenges on the glaze layer of ceramic materials. Methods Ninety-five samples of monolithic zirconia (MZ) (LuxaCam Zircon HT-Plus) and lithium disilicate (LD) (IPS e.max CAD) were divided according to the response variables: Surface roughness and surface loss (n = 10), evaluated with optical profilometry; surface topography, with scanning electron microscopy SEM (n = 3); and biofilm deposition, with microbiological assay (n = 5). The evaluations were performed in three different time evaluations: (a) Sintered, (b) Glaze, and (c) Challenge (Erosion, Abrasion, and Erosion/Abrasion). Erosion consisted in immersing specimens in HCl solution, abrasion was performed with brushing machine, and erosion/abrasion consisted of a combination of the two previous protocols. Data were analyzed with parametric tests (P Results MZ glaze layer presented significantly higher surface roughness (P = 0.00), surface loss (P = 0.03), and biofilm deposition (P = 0.00) than LD. Abrasion and erosion/abrasion showed similar outcomes, generating significantly higher surface roughness (P = 0.00), surface loss (P = 0.00), and biofilm deposition (P = 0.01) than erosion. Conclusions Glaze layer properties were altered by the challenges, with abrasion and erosion/abrasion generating higher surface roughness, surface loss, and biofilm deposition than erosion. A significant correlation was found between the surface roughness and biofilm deposition. Clinical significance The glaze layer is susceptible to challenges, especially to abrasion and erosion/abrasion, which generated greater surface roughness and surface loss than erosion. The greater surface roughness lead to a greater biofilm deposition on the glaze layer.

A evolução dos sistemas informatizados para a produção de restaurações dentárias associadas ao desenvolvimento de novas microestruturas para materiais cerâmicos causou uma mudança importante no fluxo de trabalho clínico de dentistas e técnicos, bem como nas opções de tratamento oferecidas aos pacientes. Novas microestruturas também foram desenvolvidas pela indústria para oferecer materiais cerâmicos e compósitos com propriedades otimizadas, ou seja, boas propriedades mecânicas, comportamento adequado ao desgaste e características estéticas aceitáveis. O objetivo desta revisão de literatura é discutir as principais vantagens e desvantagens dos novos sistemas cerâmicos e métodos de processamento. O manuscrito está dividido em cinco partes: I) restaurações monolíticas de zircônia; II) próteses dentárias multicamadas; III) novas vitrocerâmicas; IV) cerâmica infiltrada por polímero; e V) novas tecnologias de processamento. As cerâmicas dentárias e as tecnologias de processamento evoluíram significativamente nos últimos dez anos, com a maior parte da evolução relacionada a novas microestruturas e métodos CAD-CAM. Além disso, uma tendência ao uso de restaurações monolíticas mudou a maneira como os médicos produzem próteses dentárias totalmente em cerâmica, uma vez que as restaurações mais estéticas em várias camadas, infelizmente, são mais propensas a lascar ou delaminar. Os materiais compósitos processados ​​via CAD-CAM tornaram-se uma opção interessante, pois possuem propriedades intermediárias entre cerâmica e polímeros e são mais facilmente fresados ​​e polidos.

Made available in DSpace on 2020-12-12T02:35:32Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-05-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Objective: To evaluate the composition, flexural strength and fatigue behaviour of lithium disilicate ceramic (LD) after repeated firings and different staining techniques. Methods: LD discs were fabricated and divided according to number of firing cycles and staining technique: CO - control, discs were crystallized (850 °C/10 min); SC – single-step characterization – crystallization and staining (applied with a thin brush) were performed in a single step with one firing cycle (850 °C/10 min); and DC – double-step characterization – crystallization firing cycle was performed first (850 °C/10 min), followed by staining firing cycle (770 °C/90 s). Specimens were fired two, four or six times (one crystallization firing cycle and one, three or five staining firing cycles), resulting into 9 groups (n = 30): COII, COIV, COVI, SCII, SCIV, SCVI, DCII, DCIV and DCVI. The composition of the specimens was investigated (EDS, XRD, Raman spectroscopy), and the biaxial flexural strength (n = 10) and staircase tests (n = 20, 5 × 104 cycles, 5 Hz) were performed. Data were subjected to one-way ANOVA and Tukey's test (α = 0.05). Results: EDS and XRD revealed amorphous content for stained groups. Biaxial flexural strength was not affected by repeated firings in any group, but stained groups presented lower flexural strength than control groups (p = 0.001). The fatigue limit results decreased in all groups compared to flexural strength. SC groups showed similar (SCII and SCIV) or even higher fatigue limits (SCVI) than the control groups, and DC showed the lowest fatigue limit values. SEM and Raman suggested that the interfaces between staining and the LD showed only an overlap for the DC groups, whereas for the SC it was suggested an interaction between the stain and the LD. Significance: Repeated firings did not result in decreased lithium disilicate flexural strength.Staining affected flexural strength and also resulted in increased amorphous content in the characterized specimens. Single-step staining resulted in the highest fatigue limit. Institute of Science and Technology UNESP – Paulista State University São José dos Campos Technological Institute of Aeronautics São José dos Campos Dental School University of São Paulo Department of Dentistry University of Taubaté Institute of Science and Technology UNESP – Paulista State University São José dos Campos FAPESP: 2017-11913-8

Aim: To evaluate the fracture resistance of roots restored with CAD/CAM-fabricated posts, receiving or not intracanal laser treatment, compared with glass fiber posts under mechanical cycling. Methods: Twenty-seven endodontically treated, single-rooted teeth were divided into 3 groups: group 1 (control), prefabricated glass fiber posts relined with resin composite; group 2, CAD/CAM-fabricated intraradicular posts using Resin Nano Ceramic (RNC) blocks; and group 3, CAD/CAM-fabricated intraradicular posts using RNC blocks in canals irradiated with a 940-nm diode laser (100 mJ, 300-um optic fiber, coronal-apical and apical-coronal helical movements, speed of 2 mm/second, 4 times each canal). After cementation of the coping, cyclic loading was applied at an angle of 135° to the long axis of the root, with a pulse load of 130 N, frequency of 2.2 Hz, and 150,000 pulses on the crown at a point located 2 mm below the incisal edge on the lingual aspect of the specimen. Every 50,000 cycles, the specimens were evaluated for root fracture occurring below or above the simulated bone crest. Results were analyzed by one-way ANOVA followed by Tukey’s test (p

Objective: Evaluate the bond strength of repairs made on composite resin following the treatment of the surface of the flaw with different bonding agents and/or CO2 laser. Background: The ...

Objective: Evaluate the adhesive behavior of conventional and high-translucent zirconia after surface conditioning and hydrothermal aging. Materials and methods: Conventional (ZrC) and high-translucent zirconia (ZrT) specimens were divided into six groups: without surface treatment (ZrC and ZrT), air-borne particle abrasion with 50-μm Al2 O3 sized particles (ZrC-AO and ZrT-AO), and tribochemical treatment with 30-μm silica modified Al2 O3 sized particles (ZrC-T and ZrT-T). Zirconia specimens were treated using an MDP-containing universal adhesive and bonded to two resins blocks with an adhesive luting cement. Microbar specimens with cross-sectioned areas of 1 mm2 were achieved. Half of the microbars were subjected to hydrothermal aging. Bond strength was evaluated by microtensile bond strength test and statistically evaluated by the Weibull analysis. Results: Roughness of the ZrC-AO and ZrT-AO groups were statistically higher. Bond strength analysis revealed higher bond strength for ZrC-AO and ZrC-T groups compared to ZrT-AO and ZrT-T, respectively. Mixed failure was the most frequent for the mechanically treated groups, while no cohesive failures were obtained. Conclusion: Lower values of bond strength were obtained for the mechanically treated high-translucent zirconia groups when compared to their conventional zirconia counterparts. Mechanical surface treatment significantly improved the bond strength to conventional and high-translucent zirconia. Clinical significance: Mechanical surface treatment (air-borne particle abrasion or tribochemical treatment) associated with the use of universal adhesives containing MDP could provide a durable bonding to conventional and high-translucent zirconia. Keywords: adhesive cementation; high-translucent zirconia; microtensile bond strength.

A resina composta fotoativável é usualmente utilizada para o procedimento de colagem de bráquetes ortodônticos devido ao controle de tempo que ela proporciona. No entanto, seu uso requer cuidados antes da fotoativação propriamente dita, pois sua polimerização pode ocorrer precocemente por outras fontes de luz, que não a de um fotoativador dental (e.g. luz ambiente). Para tanto, se faz necessária a utilização da resina composta de maneira imediata na colagem dos bráquetes, com a finalidade de se evitar prejuízos no procedimento, como a perda de material. Em uma tentativa de otimizar o tempo clínico do ortodontista e diminuir os problemas associados à polimerização precoce da resina de colagem, foi idealizado um recipiente fotoprotetor. Este recipiente fotoprotetor permite o armazenamento temporário do conjunto pinças com o bráquetes preparados com resina em sua base, evitando o processo de polimerização da resina antes do momento desejado. Este estudo tem como objetivo apresentar uma descrição detalhada do procedimento de colagem de bráquetes ortodônticos estéticos cerâmicos quando se utiliza um recipiente fotoprotetor para otimizar o atendimento. A utilização do recipiente fotoprotetor mostrou-se extremamente eficiente e com um bom resultado final na satisfação, tanto do profissional quanto do paciente. O seu uso foi capaz de reduzir o tempo de cadeira do paciente durante o procedimento e impediu a polimerização precoce da resina composta de colagem utilizada.

To compare the influence of surface roughness and accelerated aging on the mechanical properties of polymer-based and ceramic CAD/CAM materials.Three polymers (Lava Ultimate [LVU], VITA ENAMIC [ENA], and Shofu Block HC [SFB]) and one ceramic (IPS Empress CAD [EMP]) were selected for this study. The specimens were treated with the aim of measuring surface roughness (Ra [mm]) and its influence on the mechanical properties. The treatments were: polishing (POL); etching with 9.6% hydrofluoric acid for 90 seconds (ETC); airborne-particle abrasion with 50-μm aluminum oxide at 2-bar pressure (SBT); and airborne-particle abrasion with 50-μm aluminum oxide at 2-bar pressure plus etching with 9.6% hydrofluoric acid (SAC) for 90 seconds. Before and after the accelerated aging (AA) protocol (30,000 cycles, 5°C and 55°C), the specimens were subjected to the 3-point bending test. The data were analyzed with two-way and three-way ANOVA and post hoc Tukey test (P.05).The surface roughness ranged from 0.24 μm to 1.96 μm, with statistically significant differences (P.05). The highest surface roughness, in descending order, was exhibited by: LVUSFBEMPENA. The AA demonstrated an influence on the flexural strength of LVU, ENA, and SFB. The surface treatment did not affect the flexural moduli of the materials tested. The LVU and SFB showed decreased moduli of resilience after the AA; however, modulus of resilience was not influenced by surface treatment.The polymer-based materials were affected by AA. In addition, surface treatment could jeopardize their mechanical properties in certain conditions.

This study investigated the effect of irradiation with an erbium-doped yttrium aluminium garnet (Er:YAG) laser and coating with silica on the surface characteristics, bond strength, and flexural strength of dental zirconia. Three hundred and forty-three standard zirconia specimens were created, and 49 were assigned to each of seven surface treatment groups: (i) no treatment; Er:YAG laser (80 mJ/2 Hz) with pulse widths of 50 μs (ii), 100 μs (iii), 300 μs (iv), or 600 μs (v); or tribochemical silica coating at the partially sintered stage (vi) or after sintering was complete (vii). All specimens were sintered after the surface treatments, except for the group in which specimens were sintered before treatment. The study outcomes were roughness, surface loss, microshear bond strength (μSBS), and biaxial flexural strength (BFS). Mean roughness and surface loss values were significantly higher in specimens from irradiated groups than in those from silica-coated groups. Regarding μSBS, after aging, specimens from all experimental groups presented very low and similar μSBS values, irrespective of the surface treatment. Silica coating after sintering yielded the highest BFS (1149.5 ± 167.6 MPa), while coating partially sintered specimens with silica resulted a BFS (826.9 ± 60.9 MPa) similar to that of the untreated control group (794.9 ± 101.7 MPa). Laser treatments, irrespective of pulse width used, significantly decreased the BFS. In the group treated with laser at 300 μs pulse width, specimens exhibited the lowest BFS value (514.1 ± 71.5 MPa). Adhesion to zirconia was not stable after aging, regardless of the surface treatment implemented.

The aims of this study were: 1) to evaluate the effect of sintering temperature on microstructure, density and flexural strength of a 3Y-TZP/TiOThe 3Y-TZP and 3Y-TZP/TiOTetragonal zirconia was identified in all groups and cubic zirconia was identified only at 3Y-TZP group. The addition of TiOThe composite developed have good aesthetic and biologics properties. However, its microstructure and mechanical properties need to be improved for future dental implant applications.

Made available in DSpace on 2020-12-12T01:19:33Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-06-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) This study aimed to produce a new SiO2+Y-TZP ceramic via uniaxial/isostatic compression that was structurally and chemically characterized relating to its translucency and flexural strength. SiO2 and Y-TZP were mixed using a ball mill, pressed and sintered at 1150 °C. The optical and mechanical properties of the specimens were compared to lithium disilicate (LD) and zirconia-reinforced lithium silicate (ZLS) (Kruskal-Wallis, α = 0.05). The Fourier Transform Infrared Spectroscopy bands suggested an interaction between Si, O and Zr. Contrast ratio and translucency parameter of the experimental ceramic were higher and lower, (p = 0.000001) respectively, than those of the LD and ZLS. The experimental ceramic presented similar flexural strength to ZLS, but lower than LD (p < 0.0001). It can be concluded that this processing method is efficient to obtain a SiO2+Y-TZP ceramic and 1150 °C crystallizes SiO2 without inducing t-m transformation. The SiO2+Y-TZP ceramic presented lower translucency and higher masking ability than the commercially available glass-ceramics, but similar flexural strength to one glass-ceramics. Department of Operative Dentistry Endodontics and Dental Materials Bauru School of Dentistry University of São Paulo Department of Prosthodontics and Periodontics Bauru School of Dentistry University of São Paulo Department of Chemistry UNESP-School of Science São Paulo State University Department of Mechanical Engineering São Carlos School of Engineering University of São Paulo Department of Physics UNESP-School of Science São Paulo State University Department of Biomaterials and Oral Biology School of Dentistry University of São Paulo Department of Pediatric Dentistry Orthodontics and Public Health Bauru School of Dentistry University of São Paulo Department of Chemistry UNESP-School of Science São Paulo State University Department of Physics UNESP-School of Science São Paulo State University FAPESP: 2017/18157-4

Purpose To evaluate the influence of specimen configuration, bonding area and zirconia surface treatment on the push out bond strength to Y-TZP and on the stress distribution using finite element analysis (FEA). Materials and methods 240 Y-TZP blocks with a central perforation were assigned to 8 groups (n=30) according to the adhesive area (macro-test: 5 × 5.5 × 4 mm and micro-test: 5 × 5.5 × 1 mm), material inserted in the perforation (resin cement or composite resin) and surface treatment (silanization or tribochemical silica coating+silanization). Push-out bond strength test, failure modes evaluation and FEA were performed. Results Three-way ANOVA showed that bond strength was statistically higher for composite resin (p=0.00) and for macro specimens (p=0.00). Surface treatment significantly increased the adhesion, except for ‘resin cement macro-test’ (p=0.00). Finite element analysis showed that the stresses were more homogeneously distributed at the interface of micro-specimens. Conclusion Macro-push out with composite resin or cement does not appear to be promising when evaluating adhesion to zirconia ceramics; micro-push out with composite resin filler is an adequate method; the tribochemical silica coating surface treatment can be evaluated by all tested methods in the current study, except for the macro-test with resin cement condition.

Objective To determine the influence of benzenesulfinic acid sodium salt 98% (BAS) and the activation mode on the polymerization behavior of experimental self-adhesive resin cements (SARCs) formulated with distinct self-etch methacrylates. Materials and methods Three catalyst-pastes using different self-etch methacrylates (2MP — bis 2-(methacryloyloxy) ethyl phosphate; 4META — 4-methacryloxyethyl trimellitic acid anhydride; and GDMAP — 1,3-glycerol dimethacrylate phosphate) and four base-pastes were formulated from the incorporation of different amounts of BAS associated to N-N-dihydroxyethyl-p-toluidine (DHPT). BAS/DHPT ratios were blended respectively based on the following final weight (wt%): control (0.0;2.0%), BP1 (0.5;1.5%), BP2 (0.8;1.2%) and BP3 (1.0;1.0%). Real-time polymerization kinetics (KP) was assessed for 10 min by FTIR spectroscopy. Maximum rate of polymerization (Rpmax) was obtained from the first derivative of the curve conversion versus time. Degree of conversion (DC) was determined over 10 min and after 24 h. SARCs were tested in self and dual activation modes. Data of Rpmax and DC 24 h were respectively analyzed by two-way ANOVA followed by Tukey’s method (α = 0.05). Results All factors and their interactions were statistically significant (p Significance The addition of BAS increased the degree of conversion of SARCs in the first minutes and 24 h after the polymerization reaction. This finding showed the importance of adding this type of salt during resin cement production to achieve better polymerization in the first minutes of the luting procedure specially when light exposure is not possible.

This study aimed to produce a new SiO

Objectives The use of thio-urethane oligomers has been shown to significantly improve the mechanical properties of resin cements (RCs). The aim of this study was to use thio-urethane-modified RC to potentially reinforce the porcelain-RC structure and to improve the bond strength to zirconia and lithium disilicate. Methods Six oligomers were synthesized by combining thiols - pentaerythritol tetra-3-mercaptopropionate (PETMP, P) or trimethylol-tris-3-mercaptopropionate (TMP, T) – with di-functional isocyanates - 1,6-Hexanediol-diissocyante (HDDI) (aliphatic, AL) or 1,3-bis(1-isocyanato-1-methylethyl)benzene (BDI) (aromatic, AR) or Dicyclohexylmethane 4,4′-Diisocyanate (HMDI) (cyclic, CC). Thio-urethanes (20 wt%) were added to a BisGMA/UDMA/TEGDMA organic matrix. Filler was introduced at 60 wt%. The microshear bond strength (μSBS), Weibull modulus (m), and failure pattern of RCs bonded to zirconia (ZR) and lithium disilicate (LD) ceramics was evaluated. Biaxial flexural test and fractographic analysis of porcelain discs bonded to RCs were also performed. The biaxial flexural strength (σbf) and m were calculated in the tensile surfaces of porcelain and RC structures (Z = 0 and Z = −t2, respectively). Results The μSBS was improved with RCs formulated with oligomers P_AL or T_AL bonded to LD and P_AL, P_AR or T_CC bonded to zirconia in comparison to controls. Mixed failures predominated in all groups. σbf had superior values at Z = 0 with RCs formulated with oligomers P_AL, P_AR, T_AL, or T_CC in comparison to control; σbf increased with all RCs composed by thio-urethanes at Z = −t2. Fractographic analysis revealed all fracture origins at Z = 0. Conclusion The use of specific thio-urethane oligomers as components of RCs increased both the biaxial flexural strength of the porcelain-RC structure and the μSBS to LD and ZR. Clinical significance The current investigation suggests that it is possible to reinforce the porcelain-RC pair and obtain higher bond strength to LD and ZR with RCs formulated with selected types of thio-urethane oligomers.

Objective: This study investigated the influence of different surface treatments on zirconia surface energy, roughness and microshear bond strength. Material and Methods: Forty eight slices of Yttria-stabilized tetragonal zirconia polycrystal (Y-TZP- VITA In-Ceram® YZ for inLab®) (6.4 x 3.2 x 1.6 mm) were divided into 3 groups according to the surface treatment (n = 16): YTZP_control -untreated; YTZP_plasma -surface treatment with non-thermal oxygen plasma; YTZP_primer - coating with ceramic primer. Surface energy (n = 6) was measured with a goniometer; and surface roughness (n = 10) was analyzed with a 3D profilometer were performed over zirconia surface. On the same specimens of surface roughness, on the treated zirconia's surface, resin cement (PANAVIA V5 - Kuraray Noritake Dental) was built up by inserting the resin cement into Tygon tubes (1 mm of internal diameter X 1 mm length). After 24 h storage, microshear test was assessed. Data were analyzed by one-way ANOVA and Tukey post-hoc test (p < 0.05). Results: Non-thermal oxygen plasma treated specimens exhibited higher statistically significant surface energy (p = 0.00) and bond strength (p = 0.00) when compared to control and primer groups. Roughness test (p = 0.897) could not detect statistical difference among the tested groups. Conclusion: Non-thermal oxygen plasma should be a suitable alternative for zirconia surface treatment prior to luting hence it improved microshear bond strength and provided higher surface energy without affecting surface roughness. Keywords Adhesion; Non-thermal plasma; Surface treatment.

Objective To investigate the effect of titania addition (0, 10 and 30 mol%) on the microstructure, relative density, Young’s modulus (E), Poisson’s ratio (υ), mechanical properties (flexural strength, σf, and Weibull modulus, m) of a Y-TZP/TiO2 composite. The effect of the presence of a biomimetic coating on the microstructure and mechanical properties was also evaluated. Methods Y-TZP (3 mol% of yttria) and Y-TZP/TiO2 composite (10 or 30 mol% of titania) were synthesized by co-precipitation. The powders were pressed and sintered at 1400°C/2 h. The surfaces, with and without biomimetic coating, were characterized by X-ray diffraction analysis and scanning electron microscopy. The relative density was measured by the Archimedes’ principle. E and υ were measured by ultrasonic pulse-echo method. For the mechanical properties the specimens (n = 30 for each group) were tested in a universal testing machine. Results Titania addition increased the grain size of the composite and caused a significant decrease in the flexural strength (in MPa, control 815.4a; T10 455.7b and T30 336.0c), E (in GPa, control 213.4a; T10 155.8b and T30 134.0c) and relative density (control 99.0%a; T10 94.4%c and T30 96.3%b) of the Y-TZP/TiO2 composite. The presence of 30% titania caused substantial increase in m and υ. Biomimetic coating did not affect the mechanical properties of the composite. Significance The Y-TZP/TiO2 composite coated with a layer of CaP has great potential to be used as implant material. Although addition of titania affected the properties of the composite, the application of a biomimetic coating did not jeopardize its reliability.

Made available in DSpace on 2022-04-28T19:43:28Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-11-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Universidade Estadual de Maringá Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Objective: To characterize the effects of aging on the nanomechanical properties and 3D surface topographical parameters of an experimental Zirconia Toughened Alumina (ZTA) composite compared to its respective individual counterpart materials. Methods: Disk-shaped specimens comprised of three material groups were processed: 1) ZTA 70/30 (70% alumina reinforced with 30% second-generation 3Y-TZP); 2) Zpex (Second-generation 3Y-TZP), and; 3) Al2O3 (High purity Alumina) (n = 10/material, 12 × 1 mm). After synthesis, ceramic powders were pressed, the green-body samples were sintered and polished. Nanoindentation testing was performed to record elastic modulus (E) and hardness (H). Interferometry was utilized to assess 3D surface roughness parameters (Sa, Sq), while X-ray diffraction (XRD) and scanning electron microscope (SEM) assessed the crystalline content and microstructure. All tests were performed before and after simulated aging (134°C, 2.2 bar, 20 h). Statistical analyses were performed using linear mixed-model and least square difference pos-hoc tests (α = 5%). Results: XRD spectra indicated increase of monoclinic peaks for Zpex (~18%) relative to ZTA 70/30 (~2.5%) after aging. Additionally, aging did not affect the surface roughness parameters of ZTA 70/30 and Al2O3, although a significant increase in Sa was recorded for Zpex following aging (~90 nm) (p < 0.001). Al2O3 yielded the highest H and E values (H:21 GPa, E: 254 GPa), followed by ZTA 70/30 (H: 13 GPa, E: 214 GPa) and Zpex (H:11 GPa, E: 167 GPa), all significantly different (p < 0.03). Conclusion: ZTA 70/30 and Al2O3 presented high hydrothermal stability with respect to all evaluated variables, where artificial aging significantly increased the monoclinic content and surface roughness of Zpex. Department of Prosthodontics and Periodontology University of São Paulo - Bauru School of Dentistry Department of Biomaterials New York University College of Dentistry Hansjörg Wyss Department of Plastic Surgery NYU Langone Medical Center Department of Mechanical and Aerospace Engineering NYU Tandon School of Engineering Department of Biomedical Engineering NYU Tandon School of Engineering Department of Biomaterials and Oral Biology University of São Paulo School of Dentistry Institute of Research in Nuclear Energy Department of Physics São Paulo State University Analytical Laboratory of Restorative Biomaterials - LABiom-R Federal Fluminense University (UFF) School of Dentistry Niteroi Technological Institute of Aeronautics (ITA) Integrated Biomedical Engineering and Health Sciences McMaster University Department of Physics São Paulo State University FAPESP: 2012/19078-7 Universidade Estadual de Maringá: 2016/17793-1 Universidade Estadual de Maringá: 2016/18818-8 Universidade Estadual de Maringá: 2017/19362-0 Universidade Estadual de Maringá: 2018/03072-6 Universidade Estadual de Maringá: 2019/00452-5 Universidade Estadual de Maringá: 2019/08693-1 CNPq: 304589/2017-9 CNPq: 434487/2018-0

Glass-infiltrated ceramic biocomposites have shown high strength and toughness, which results in long lifetime, but their translucency is relatively low, limiting the aesthetic quality of dental restorations. This study evaluated the effects of glass compositions based on the system SiO 2 -B 2 O 3 -Al 2 O 3 -La 2 O 3 -TiO 2 -CaO-CeO 2 , designed using SciGlass software, on the optical properties of alumina-based biocomposites. For (45-x)SiO 2 -xB 2 O 3 -25Al 2 O 3 -15La 2 O 3 -15TiO 2 glasses, the increase in B 2 O 3 content enhanced the infiltration of glass in the alumina preform because of the decrease in glass viscosity. The addition of CaO enhanced the infiltration depth and increased light transmittance of the biocomposite in the visible region (wavelength between 360 and 740 nm); however, the addition of CeO 2 significantly decreased the transmittance, particularly at the low wavelength range, because of the coloring effect (yellowish color due to the formation of cerium-titanium complexes). The highest transmittance was measured for biocomposites infiltrated with glass of composition 25% SiO 2 -20% B 2 O 3 -20% Al 2 O 3 -15% La 2 O 3 -15% TiO 2 -5% CaO (mol%).

The purpose of this study was to evaluate color stability of two dental ceramics cemented with two resin cements, assessing the color difference (ΔE00) by the measurement of L*, a*, b*, c* and h* of transmittance. The combination of two ceramic system (feldspathic and lithium disilicate) and two resin cements - color A3 (RelyX ARC and Variolink II) resulted in 4 groups (n=5). Ten disks-shaped specimens were fabricated for each ceramic system (10x1.5 mm), etched with hydrofluoric acid (10%) and silanized prior to cementation. The color analysis was performed 24 h after cementation of the samples and after 6 months of storage in relative humidity by means of spectrophotometry. The ΔE00 values were analyzed statistically by two-way ANOVA followed by the Tukey test (p

This study evaluated the impact of tooth shade on differences in color (Delta E), lightness (Delta L), chromaticity coordinates a*/b* (Delta alpha and Delta b), transmittance and the degree of fluorescence of CAD/CAM leucite based ceramic (LBC). Ten disks were fabricated of LBC;Empress CAD, A2, thickness of 1.5 mm and eight disks of resin-nano-ceramic (RNC;Lava Ultimate) in different colors to simulate variations in substrate shade. The associations of LBC disks with different color substrates were analyzed with a spectrophotometer;AE, Delta L*, Delta a*, Delta b*, and transmittance were measured and calculated. Fluorescence was evaluated with a fluorescence system (Fluorescence System, Biopdi). All substrate shades influenced the optical properties of LBC, with regard to color, luminosity, coordinate a* and b*, transmittance, and fluorescence (p

To evaluate the effect of two aging methods (mechanical cycling and autoclave) on the mechanical behavior of veneer and framework ceramic specimens with different configurations (monolithic, two and three-layers).Three ceramics used as framework for fixed dental prostheses (YZ-Vita In-Ceram YZ; IZ-Vita In-Ceram Zirconia; AL-Vita In-Ceram AL) and two veneering porcelains (VM7 and VM9) were studied. Bar-shaped specimens were produced in three different designs: monolithic, two layers (porcelain-framework) and three layers (porcelain-framework-porcelain). Specimens were tested for three-point flexural strength at 1MPa/s in 37°C artificial saliva. Three different experimental conditions were evaluated (n=10): control; mechanical cycling (2Hz, 37°C artificial saliva); and autoclave aging (134°C, 2 bars, 5h). Bi-layered specimens were tested in both conditions: with porcelain or framework ceramic under tension. Fracture surfaces were analyzed using stereomicroscope and scanning electron microscopy. Results were statistically analyzed using Kruskal-Wallis and Student-Newman-Keuls tests.Only for AL group, mechanical cycling and autoclave aging significantly decreased the flexural strength values in comparison to the control (p0.01). YZ, AL, VM7 and VM9 monolithic groups showed no strength degradation. For multi-layered specimens, when the porcelain layer was tested in tension (bi and tri-layers), the aging methods evaluated also had no effect on strength (p≥0.05). Total and partial failure modes were identified.Mechanical cycling and autoclave aging protocols had no effect on the flexural strength values and failure behavior of YZ and IZ ceramic structures. Yet, AL monolithic structures showed a significant decrease in flexural strength with any of the aging methods.

SUMMARYThe aim of this study was to evaluate the influence of finishing and polishing systems and toothbrush abrasion on transmittance (T) and surface roughness (Ra) of three composite resins (Filtek Z350 XT, Tetric N-Ceram, and IPS Empress Direct). Eighteen resin disks (10 mm diameter × 2 mm thick) finished by polyester strips had initial surface smoothness recorded, representing phase 1 (P1). Specimens were divided into three groups (n=6) according to the finishing/polishing instrument used (OneGloss, TopGloss, and Sof-Lex) to compose phase 2 samples (P2). Then specimens were subjected to 514 cycles of toothbrush simulation using a toothpaste slurry, with a constant load applied to soft bristles, and were then washed (phase 3=P3). After each phase, the specimens were examined by an optical profiler and spectrophotometer to measure Ra and T. Data were analyzed by analysis of variance, Tukey and Pearson tests. T values were statistically influenced by composite resin ( p=0.000) and phase of measurement ( p=0.000) factors, while the finishing/polishing system used ( p=0.741) did not affect T. On the other hand, Ra values were statistically affected by the factor finishing/polishing system ( p=0.000), but not by composite resin ( p=0.100) and phase of measurement ( p=0.451). Tetric N-Ceram and Empress Direct presented higher values of roughness when polished by OneGloss, while TopGloss and Sof-Lex showed a lower roughness. It can be concluded that composite resins transmitted more light after dental abrasion. Transmittance of composite resins was not modified by the distinct roughness created by finishing/polishing instruments.

Dental prostheses made of ceramic composites infiltrated with glasses have been used due to their biocompatibility and possibility to mimic the natural teeth. In this study, the devitrification behavior of 20SiO2-25B2O3-25Al2O3-15La2O3-15TiO2 glass during the infiltration process in a porous alumina preform was investigated. Glass frits were prepared by melting the raw materials at 1500 °C for 60 min. The glass was infiltrated into the alumina preform at 1,150 or 1,200 °C for 60 min. The specimens were characterized by X-ray diffraction analysis and scanning electron microscopy. After the infiltration, it was possible to note that the devitrification process occurred in the remaining glass (excess glass that did not infiltrate in the preform), forming mostly aluminum borate and mullite crystalline phases. However, within the infiltrated composite no devitrification was noticed in the infiltrated glass. Possible explanations for this behavior are discussed.

Made available in DSpace on 2020-12-10T19:55:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-04-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) EMU Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Purpose: To synthesize a zirconia-toughened alumina (ZTA) composite with 85% alumina matrix reinforced by 15% zirconia and to characterize its optical and mechanical properties before and after artificial aging, to be compared with a conventional dental zirconia (3Y-TZP). Material and methods: After syntheses, ZTA and 3Y-TZP powders were uniaxially and isostatically pressed. Green-body samples were sintered and polished to obtain 80 disc-shaped specimens per group (12 x 1 mm, ISO 6872:2015). The crystalline content and microstructure were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). Optical properties were determined by the calculation of contrast ratio (CR) and translucency parameter (TP) using reflectance data. Mechanical properties were assessed by Vickers hardness, fracture toughness and biaxial flexural strength test (BFS). All analyses were conducted before and after artificial aging (20h, 134 degrees C, 0.22 MPa). Optical parameters and microhardness differences were evaluated through repeated-measures analysis of variance (p < 0.05). BFS data were analyzed using Weibull statistics (95% CI). Results: The synthesis of the experimental ZTA composite was successful, with 98% of theoretical density, as shown in the SEM images. XRD patterns revealed typical zirconia and alumina crystalline phases. ZTA optical properties parameters showed no effect of aging, with a high CR and low TP values denoting a high masking-ability. 3Y-TZP presented lower masking-ability and aging significantly affected its optical properties. ZTA Vickers hardness, fracture toughness and Weibull parameters, including characteristic stress and Weibull modulus were not influenced by aging, while 3Y-TZP presented a significant decrease in characteristic stress and increase in fracture toughness after aging. The ZTA probability of survival for missions of 300 and 500 MPa was estimated at similar to 99% validating its use for 3-unit posterior fixed dental prostheses (FDP), and no different from conventional 3Y-TZP. At high-stress mission (800 MPa) a significant decrease in probability of survival was observed for aged 3Y-TZP (84%) and for immediate and aged ZTA (73 and 82% respectively). Conclusion: The ZTA composite presented a dense microstructure, with preservation of the crystalline content, optical and mechanical properties after artificial aging, which encourages future research to validate its potential use for large span FDP. Univ Sao Paulo, Dept Prosthodont & Periodontol, Bauru Sch Dent, Al Otavio Pinheiro Brisola 9-75, BR-17012901 Bauru, SP, Brazil Univ Sao Paulo, Sch Dent, Dept Biomat & Oral Biol, Sao Paulo, SP, Brazil Nucl & Energy Res Inst, Sao Paulo, SP, Brazil Sao Paulo State Univ, Dept Phys, Bauru, SP, Brazil NYU, Coll Dent, Dept Biomat & Biomimet, New York, NY USA NYU Langone Med Ctr, Hansjorg Wyss Dept Plast Surg, New York, NY USA NYU Tandon Sch Engn, Mech & Aerosp Engn, New York, NY USA Univ Sao Paulo, Bauru Sch Dent, Dept Biol Sci, Discipline Pharmacol, Sao Paulo, SP, Brazil Sao Paulo State Univ, Dept Phys, Bauru, SP, Brazil FAPESP: 2012/19078-7 EMU: 2016/18818-8 CNPq: 304589/2017-9 CNPq: 434487/2018-0 CAPES: 001 FAPESP: 2016/24165-7 FAPESP: 2016/18657-4 FAPESP: 2016/17793-1 FAPESP: 2017/19362-0 FAPESP: 2018/03072-6 FAPESP: 2019/00452-5 FAPESP: 2019/14798-0 FAPESP: 2019/08693-1

This study compared the fatigue performance and the stress distribution of endodontically treated molars restored with endocrowns obtained with lithium disilicate glass-ceramic or a polymer-infiltrated ceramic network, both processed by CAD-CAM, and direct composite restorations. Forty-eight human mandibular molars were randomly assigned into 03 groups (n = 16) and restored with endocrowns (LD – lithium disilicate glass-ceramic or PICN – polymer-infiltrated ceramic network) or with direct composite restorations. Fatigue testing followed a step-stress approach (initial maximum load of 200 N and 5000 cycles, incremental step load of 200N and 10,000 cycles/step, being the specimens loaded until failure or to a maximum of 135,000 cycles at 2800 N). The fatigue failure load and number of cycles until failure were recorded and statistically analyzed. Fractographic and finite element (FEA) analyzes were conducted as well. There were no differences in fatigue failure load, number of cycles until fracture and mean survival probabilities among groups. However, indirect endocrowns had higher mechanical structural reliability, and LD restorations lasted more time before start to failing. FEA showed that the stress concentration in tooth tissues was higher for the resin composite, followed by PICN and LD in a decreasing order. Almost all fractures were restricted to the restorative material (without tooth involvement), and origins were identified at occlusal surface. The type of restoration did not influence the fatigue failure load, number of cycles until fracture and mean survival probabilities of the restorative strategies. Despite that, the mechanical structural reliability of endocrowns, especially those made of lithium disilicate, was higher and lasted more time before start to failing.