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  • ItemArtigo
    Development of Y-TZP/MWCNT-SiO2 nanocomposite for dental protheses
    (2023-07-01) da Silva, Lucas Hian; Rinaldi, Laura Ajamil; Lazar, Dolores Ribeiro Ricci; Ussui, Valter; Tango, Rubens Nisie [UNESP]; Belli, Renan; Lohbauer, Ulrich; Cesar, Paulo Francisco; Universidade de São Paulo (USP); Nuclear and Energy Research Institute (IPEN); Universidade Estadual Paulista (UNESP); Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU)
    Y-TZP/MWCNT-SiO2 nanocomposite was synthesized by co-precipitation and hydrothermal treatment methods. After the characterization of the MWCNT-SiO2 powder, specimens were obtained from the synthesized material Y-TZP/MWCNT-SiO2 by uniaxial pressing for a second characterization and later comparison of its optical and mechanical properties with the conventional Y-TZP. The MWCNT-SiO2 was presented in bundles of carbon nanotubes coated by silica (mean length: 5.10 ± 1.34 μm /D90: 6.9 μm). The composite manufactured was opaque (contrast ratio: 0.9929 ± 0.0012) and had a white color with a slightly difference from the conventional Y-TZP (ΔE00: 4.4 ± 2.2) color. The mechanical properties of Y-TZP/MWCNT-SiO2: vickers hardness (10.14 ± 1.27 GPa; p = 0.25) and fracture toughness (4.98 ± 0.30 MPa m1/2; p = 0.39), showed no significant difference from the conventional Y-TZP (hardness: 8.87 ± 0.89; fracture toughness: 4.98 ± 0.30 MPa m1/2). However, for flexural strength (p = 0.003), a lower value was obtained for Y-TZP/MWCNT-SiO2 (299.4 ± 30.5 MPa) when compared to the control Y-TZP (623.7 ± 108.8 MPa). The manufactured Y-TZP/MWCNT-SiO2 composite presented satisfactory optical properties, however the co-precipitation and hydrothermal treatment methods need to be optimized to avoid the formation of porosities and strong agglomerates, both from Y-TZP particles and MWCNT-SiO2 bundles, which lead to a significant decrease in the material flexural strength.
  • ItemErrata
    Sem título
    (2023-04-01) Silveira, Marcos Paulo Motta [UNESP]; Ramos, Nathália de Carvalho [UNESP]; Lopes, Guilherme da Rocha Scalzer [UNESP]; Tribst, João Paulo Mendes; Bottino, Marco Antonio [UNESP]; Universidade Estadual Paulista (UNESP); University of Taubaté (UNITAU); The University of Amsterdam and Vrije Universiteit
    Error in Figure In the original publication [1], there was a mistake in Figure 2 as published. “Aging” labels referring to “Yes” and “No” on the figure were switched. The corrected Figure 2 appears below. The authors state that the scientific conclusions are unaffected. This correction was approved by the Academic Editor. The original publication has also been updated.
  • ItemArtigo
    Stress distribution on implant- supported zirconia crown of maxillary first molar: effect of oblique load on natural and antagonist tooth
    (2023-01-01) Leandro, Lisliane Nara Rossi; Barra Grande, Mateus Favero [UNESP]; Pelegrine, André Antônio; Nishioka, Renato Sussumu [UNESP]; Teixeira, Marcelo Lucchesi; Basting, Roberta Tarkany; Faculdade São Leopoldo Mandic; Universidade Estadual Paulista (UNESP)
    This study evaluated the stress distribution on an implant-supported zirconia crown of a mandibular first molar subjected to oblique loading by occlusal contact with the natural maxillary first molar by using the 3D finite element method. Two virtual models were made to simulate the following situations: (1) occlusion between maxillary and mandibular natural first molars; (2) occlusion between zirconia implant-supported ceramic crown on a mandibular first molar and maxillary natural first molar. The models were designed virtually in a modeling program or CAD (Computer Aided Design) (Rhinoceros). An oblique load of 100 N was uniformly applied to the zirconia framework of the crown. The results were obtained by the Von Mises criterion of stress distribution. Replacement of the mandibular tooth by an implant caused a slight increase in stress on portions of the maxillary tooth roots. The crown of the maxillary model in occlusion with natural antagonist tooth showed 12% less stress when compared with the maxillary (model in occlusion with the) implant-supported crown. The mandibular crown of the implant show 35% more stress when compared with the mandibular antagonist crown on the natural tooth. The presence of the implant to replace the mandibular tooth increased the stresses on the maxillary tooth, especially in the region of the mesial and distal buccal roots.
  • ItemArtigo
    Fatigue survival of endodontically treated teeth restored with different fiber-reinforced composite resin post strategies versus universal 2-piece fiber post system: An in vitro study
    (2023-03-01) Penteado, Marcela Moreira [UNESP]; de Andrade, Guilherme Schmitt [UNESP]; Araujo, Rodrigo Máximo [UNESP]; Borges, Alexandre Luiz Souto [UNESP]; Valandro, Luiz Felipe; Pereira, Gabriel Kalil Rocha; da Silva, João Maurício Ferraz [UNESP]; Universidade Estadual Paulista (UNESP); Universidade Federal de Sergipe (UFS)
    Statement of problem: Various strategies have been proposed to reduce the cement space of foundation restorations for endodontically treated teeth. However, they may add more operative steps, or the dentist must keep different sizes of drills and posts in stock. A 2-piece universal adjustable post system has been developed to overcome this problem, but whether the system has acceptable fatigue survival performance is unclear. Purpose: The purpose of this in vitro study was to evaluate the fatigue survival and stress distribution of endodontically treated teeth without a ferrule and restored with different glass fiber post strategies versus a recently introduced universal 2-piece fiber post system. Material and methods: Bovine incisor roots were randomly assigned to 3 groups as per the post used (n=13): adapted glass fiber post with post space preparation of the same size, composite resin-custom glass fiber post (CTM), and universal 2-piece glass fiber-reinforced composite resin post (UNI). The posts were adhesively luted, the composite resin core was added, and a composite resin crown was produced with computer-aided design and computer-aided manufacturing (CAD-CAM), and then adhesively luted to each core. A fatigue test was performed with the stepwise stress method (10 000 cycles/step; 20 Hz; load=100 N to 750 N; step=50 N) until fracture, and the failure mode analyzed. The stress distribution was evaluated by finite element analysis with the maximum principal stress criteria by following the parameters of the in vitro test. The solids were considered homogeneous, linear, and isotropic, except for the glass fiber post (orthotropic), and a load of 450 N at 30 degrees was applied. The fatigue failure load and the number of cycles for failure were analyzed with Kaplan-Meier and Mantel-Cox (log rank test) (α=.05). The finite element analysis results were analyzed with colorimetric graphs. Results: The highest fatigue failure load and the number of cycles for failure were found in the UNI system, whereas the lowest results were found in the CTM group. All groups exhibited repairable failures. The finite element analysis showed the lowest stress in root dentin in the UNI system. The CTM system had the largest stress regions at the dentin and dentin-core interface. Conclusions: The use of a 2-piece universal glass fiber post system resulted in more fatigue behavior compared with composite resin-custom glass fiber posts.
  • ItemArtigo
    EFFECT OF SURFACE TREATMENT ON FLEXURAL STRENGTH AND SUBCRITICAL CRACK GROWTH OF LITHIUM DISILICATE: AN IN VITRO STUDY
    (2023-01-20) DE CARVALHO, Ronaldo Luís Almeida; Miranda, Jean Soares; Ramos, Nathália de Carvalho; Weitzel, Isabela Sandim Souza Leite; Amaral, Marina; Kimpara, Estevão Tomomitsu [UNESP]; Centro Universitário Braz Cubas; Universidade Federal de Juiz de Fora; Universidade São Francisco: Bragança Paulista; Universidade de Taubate; Universidade Estadual Paulista (UNESP)
    Alternative surface treatments have been proposed for the cementation of lithium disilicate ceramics aiming to improve adhesive and flexural strength under fatigue. This study aimed to evaluate the slow crack growth (SCG) parameters of the lithium disilicate ceramic after hydrofluoric acid (HF) etching or air abrasion (AB) as surface treatments. Ceramic discs were treated with HF (5%, 20 s) or AB (30 µm silica-modified alumina particles, 2.8 bar, 10 mm distance, 15 s), and received a layer of resin cement. The surface roughness after surface treatment was evaluated (n = 5). Samples were tested in a piston-on-three-ball assembly to evaluate the flexural strength (n = 20), inert strength (n = 25), and to determine SCG parameters n and D (n = 35). The highest roughness (p < 0.01) was observed in the AB group, with the highest reliability according to the Weibull analysis, but the lowest SCG susceptibility. Flexural (p = 0.03) and inert strength (p < 0.01) were the greatest in the HF group. Despite exhibiting lower strength than 5% HF, air abrasion may be an alternative for the surface treatment of lithium disilicate surfaces, indicating the best prognosis over time.
  • ItemArtigo
    Fluoride and Calcium Release from Alkasite and Glass Ionomer Restorative Dental Materials: In Vitro Study
    (2023-02-01) Di Lauro, Alessandro; Di Duca, Fabiana; Montuori, Paolo; Dal Piva, Amanda Maria de Oliveira; Tribst, João Paulo Mendes; Borges, Alexandre Luiz Souto [UNESP]; Ausiello, Pietro; University of Naples Federico II; University of Amsterdam and Vrije Universiteit Amsterdam; Universiteit van Amsterdam and Vrije Universiteit Amsterdam; Universidade Estadual Paulista (UNESP)
    This study evaluated the effect of pH and temperature on the ion (F− and Ca2+) release of a resin-based material containing alkaline fillers and a self-setting high-viscous glass ionomer cement. Disks were prepared according to manufacturers’ instructions for both materials: the EF group (Equia Forte HT filling, GC) and the CN group (Cention N, Ivoclar). Specimens were immersed in 50 mL buffer solution with three different pHs (4.8, 6.8, and 8.8), and stored at 0°, 18°, 37°, and 44 °C. After 24 h, 7 d, and 28 d, cumulative F− and Ca2+ releases were analyzed by chromatography and mass spectrometry, and pH was measured. Both materials showed minimal changes in pH with final values after 28 d of 5.17 ± 0.56 for CN and 5.12 ± 0.24 for EF. In all experimental conditions, the percentages of ion release were higher for EF than for CF. In particular, both materials showed a significant difference in temperature in F− release. Regardless of the pH values, the highest Ca2+ ion release was after 28 days, with a significant difference in temperature for CN and EF. Within the limit of this study, the temperature storage influenced ion release and the high-viscous glass ionomer showed the maximum values.
  • ItemArtigo
    Effect of Resin Cement at Different Thicknesses on the Fatigue Shear Bond Strength to Leucite Ceramic
    (2022-01-01) Arcila, Laura Viviana Calvache [UNESP]; Gomes, Laís Carolina Landim [UNESP]; Ortiz, Laura Patricia Nadal [UNESP]; Costa, Mardoqueu M. Da; Tribst, João Paulo Mendes; Bottino, Marco Antonio [UNESP]; Saavedra, Guilherme De Siqueira Ferreira Anzaloni [UNESP]; De Melo, Renata Marques [UNESP]; Universidade Estadual Paulista (UNESP); Brasil University; University of Amsterdam and Vrije Universiteit Amsterdam
    Objectives This in vitro study was performed to evaluate fatigue survival by shear test in the union of leucite-reinforced feldspathic ceramic using different cement thicknesses. Materials and Methods Leucite-reinforced glass ceramics blocks were sectioned in 2-mm thick slices where resin cylinders were cemented. The samples were distributed in two experimental groups (n = 20) according to the cement thickness (60 and 300 μm). The specimens of each group were submitted to the stepwise fatigue test in the mechanical cycling machine under shear stress state, with a frequency of 2 Hz, a step-size of 0.16 bar, starting with a load of 31 N (1.0 bar) and a lifetime of 20,000 cycles at each load step. Results The samples were analyzed in a stereomicroscope and scanning electron microscopy to determine the failure type. There is no significant difference between the mean values of shear bond strength according to both groups. Log-rank (p = 0.925) and Wilcoxon (p = 0.520) tests revealed a similar survival probability in both cement layer thicknesses according to the confidence interval (95%). The fracture analysis showed that the mixed failure was the most common failure type in the 300-μm thickness group (80%), while adhesive failure was predominant in the 60-μm thickness group (67%). The different cement thicknesses did not influence the leucite ceramic bonding in fatigue shear testing; however, the thicker cement layer increased the predominance of the ceramic material failure. Conclusion The resin cement thicknesses bonded to leucite ceramic did not influence the long-term interfacial shear bond strength, although thicker cement layer increased the ceramic material cohesive failure. Regardless the cement layer thickness, the shear bond strength lifetime decreases under fatigue.
  • ItemArtigo
    Influence of CAD/CAM Abutment Heights on the Biomechanical Behavior of Zirconia Single Crowns
    (2022-12-01) de Matos, Jefferson David Melo [UNESP]; Gomes, Leonardo Silva [UNESP]; de Carvalho Ramos, Nathália [UNESP]; Queiroz, Daher Antonio; Tribst, João Paulo Mendes; Campos, Tiago Moreira Bastos; Borges, Alexandre Luiz Souto [UNESP]; da Rocha Scalzer Lopes, Guilherme [UNESP]; Bottino, Marco Antonio [UNESP]; Paes Junior, Tarcisio José Arruda [UNESP]; University of Florida; Universidade Estadual Paulista (UNESP); Universidade São Francisco (USF); University of Taubaté (UNITAU); The University of Texas Health Science Center at Houston (UTHealth); University of Amsterdam and Vrije Universiteit; Technological Institute of Aeronautics
    The biomechanical behavior of the universal link (titanium base) prosthetic abutment with different heights in implant-supported restorations was evaluated. Forty regular implants (4 × 10 mm) in titanium were used, divided into two groups according to the abutment height (n = 20): 4.5 × 4 mm (short) and 4.5 × 5.5 mm (long). Using CAD/CAM technology, zirconia crowns were milled and cemented onto the prosthetic abutments. Half of the specimens were submitted to the initial maximum fracture load test in a universal testing machine. The long abutments presented fracture load (41.1 ± 6.96 kgf) statistically similar to the short abutments (49.5 ± 7.68 kgf). The other half of the specimens were submitted to mechanical cycling (2,000,000 cycles, 2 Hz with a stainless-steel antagonist with a diameter of 1.6 mm), following ISO 14801:2007. Subsequently, the survival of the specimens was evaluated using the survival analysis function, Kaplan–Meier and Mentel–Cox (log- rank) (p < 0.05). The finite element analysis was performed in similar conditions to those used for the in vitro test through computer-aided engineering software (version 19.2, ANSYS Inc., Houston, TX, USA). The biomechanical behavior of both models was similar regardless of the evaluated structure of the set. It was concluded that both short and long abutment presents promising fatigue behavior and stress distribution for use in long-term implant-supported restorations.
  • ItemArtigo
    Influence of Optional Crystallization Firing on the Adhesion of Zirconia-Reinforced Lithium Silicate before and after Aging
    (2022-12-01) Rodrigues, Murilo Rocha [UNESP]; Grangeiro, Manassés Tercio Vieira [UNESP]; Rossi, Natalia Rivoli [UNESP]; de Carvalho Ramos, Nathalia [UNESP]; de Carvalho, Rodrigo Furtado; Kimpara, Estevão Tomomitsu [UNESP]; Tribst, João Paulo Mendes; de Arruda Paes Junior, Tarcisio José [UNESP]; Universidade Estadual Paulista (UNESP); Federal University of Juiz de Fora; Universiteit van Amsterdam and Vrije Universiteit Amsterdam
    This study proposed to evaluate the influence of the crystallization firing process and the hydrothermal degradation on the bond strength between different reinforced glass-ceramics and resin cement. Material and Methods: zirconia-reinforced lithium silicate (ZLS) and lithium disilicate (LD) were divided into six groups according to aging simulation (baseline or after thermocycling) and restorative approach (ZLS without firing; ZLS with firing; LD with firing). ZLS and LD surfaces were etched with 5% hydrofluoric acid for 30 s and 20 s, respectively, and then received a layer of silane coupling agent (Monobond-N). Then, cylinders of resin cement (1 mm diameter × 2 mm height) were bonded onto their surfaces. The baseline samples were immersed in distilled water for 24 h before the microshear bond strength (µSBS) test, while half of the specimens were tested after 6000 cycles of thermocycling aging. The types of failures were analyzed through stereomicroscopic and scanning electron microscope. The failure modes were classified as adhesive, predominantly adhesive, cohesive in ceramic, or cohesive in cement. The µSBS data were analyzed by two-way ANOVA and Tukey’s test. A restorative approach (p = 0.000) and aging (p = 0.000) affected the bond strength. The highest bond-strength values were observed in the ZLS without the optional crystallization firing. The most frequent failures were adhesive and predominantly adhesive. The cementation of zirconia-reinforced lithium silicate without the optional crystallization firing process leads to high bond-strength values with resin cement.
  • ItemArtigo
    Biomechanical Behavior of Different Miniplate Designs for Skeletal Anchorage in the Anterior Open Bite Treatment
    (2022-12-01) Ielpo, Ana Paula Macarani [UNESP]; de Matos, Jefferson David Melo [UNESP]; Noritomi, Pedro Yoshito; da Rocha Scalzer Lopes, Guilherme [UNESP]; Queiroz, Daher Antonio; Borges, Alexandre Luiz Souto [UNESP]; Nascimento, Rodrigo Dias [UNESP]; Universidade Estadual Paulista (UNESP); University of Florida (UFHealth); Renato Archer Information Technology Center; The University of Texas Health Science Center Houston (UTHealth)
    This study aimed to evaluate the stress distribution and mechanical behavior of miniplate designs to skeletal anchorage for the treatment of anterior open bite in adult patients. A complete hemimaxilla, teeth, brackets, transpalatal bar, and three miniplates were virtually modeled. I-, Y-, and T-shaped miniplates were installed in the area of the alveolar zygomatic crest. The assembly was constricted and three intrusive forces (2, 4, and 6 N) were applied to the maxillary molars and anchorage according to the miniplates. All materials were considered homogeneous, elastic, and linear; the mesh was 1,800,000 hexahedrons with 2,800,000 nodes on average. Displacement, maximum principal stress, and von Mises stress were evaluated according to the shape of the anchorage device and intrusive force. The miniplate configurations resulted in different stress and displacement intensities in the bone tissue and plate; these stresses were always located in the same regions and were within physiological limits. The Y-plate showed the best performance since its application generated less stress in bone tissue with less displacement.
  • ItemArtigo
    Resin cement coating reverts the machining damage on the flexural fatigue strength of lithium disilicate glass-ceramic
    (2023-04-01) May, Michele Mirian; Machry, Renan Vaz; Fraga, Sara; de Andrade, Guilherme Schmitt [UNESP]; Bottino, Marco Antonio [UNESP]; Valandro, Luiz Felipe; May, Liliana Gressler; Federal University of Santa Maria; Federal University of Rio Grande do Sul; Universidade Estadual Paulista (UNESP)
    This study evaluated the effect of resin cement coating with high and low viscosities on the flexural fatigue strength of machined lithium disilicate glass-ceramic. Discs (IPS e.max CAD; Ivoclar Vivadent) were prepared and divided according to the surface condition (machining [M]—CEREC inLab; and polishing [P]—laboratory procedures), resin cement coating (with or without), and cement viscosity (high [H] and low [L]). The ceramic bonding surface was etched/primed by a one-step primer application followed by resin cement application (Variolink N base + high or low viscosity catalyst; Ivoclar Vivadent). Biaxial flexural fatigue strength was evaluated on a piston-on-three-ball set by the step-test method (n = 15) (initial stress: 60 MPa; incremental steps: 20 MPa; 10,000 cycles/step, at 20 Hz). Weibull statistics were used for fatigue data. Contact angle, topographic, and fractographic analysis were also performed. Machining produced statistically lower contact angle than polishing and a significant detrimental effect on the fatigue behavior (σ0M = 247.2 [246.9–268.3]; σ0P = 337.4 [297.8–382.4]). Machined groups followed by resin cement coating (σ0MH = 297.9 [276.0–321.5]; σ0Ml = 301.2 [277.1–327.4]) behaved similarly to the polished and coated groups (σ0PH = 342.0 [308.9–378.5]; σ0PL = 357.3 [324.7–393.1]), irrespective of the cement viscosity. Therefore, cement coating has able to revert the detrimental effects of the machining on the fatigue strength of lithium disilicate glass-ceramic. High and low viscosity cements behaved similarly in the improvement of CAD–CAM lithium disilicate fatigue strength.
  • ItemArtigo
    Glycol thermal synthesis of the 45B5 bioactive borate glass: Structural, physical, and apatite mineralization in vitro
    (2023-04-01) dos Santos, Verônica Ribeiro; Campos, Tiago Moreira Bastos; Thim, Gilmar Patrocínio; Borges, Alexandre Luiz Souto [UNESP]; de Sousa Trichês, Eliandra; Universidade Federal de São Paulo (UNIFESP); Aeronautic Technological Institute; Universidade Estadual Paulista (UNESP)
    This work was performed aiming to develop a new and straightforward route for bioactive glasses obtention with minimal equipment and explore the structural, physical, and bioactivity properties of the resulting glass and its glass ceramics. Herein, the synthesis of the borate bioactive glass in the 45B5 composition (46.1 B2O3 – 26.9 CaO – 24.4 NaO – 2.6 P2O5, mol%) by the glycol thermal method was proposed; an original chemical route for bioactive glass obtention based on transesterification reaction between the precursors with a glycol. The suggested mechanism for the borate network formation was proven accurate, revealing a vitreous structure formed by ring-type metaborate structural units with a lamellar morphology upon calcination. Glass-ceramics obtained at 500 (45B5-500) and 700 °C (45B5-700) indicate the oxides were effectively incorporated into the network by crystallization of Ca–Na–B, Ca–B, and Na–B phases. The in vitro apatite mineralization assay performed on the glass and glass-ceramics revealed their great solubility and conversion rate into hydroxyapatite (HA, Ca5(PO4)3(OH)), which is taken as an indication of bioactivity. Besides HA, however, calcium carbonate species were identified at the early stages of mineralization for 45B5 and 45B5-500, suggesting the 45B5-700 glass-ceramic has a higher ability to form apatite as the majority of Ca2+ are directed to precipitate into hydroxyapatite. Overall, the 45B5 glass and glass-ceramics demonstrated their great bioactivity, having high application potential in soft tissue engineering on wound healing materials and devices, as incorporation in hydrogels and nanofibers. Furthermore, the glycol thermal method generated new perspectives for the synthesis of a broad range of bioactive glasses compositions and their application in tissue engineering.
  • ItemArtigo
    Silica infiltration on translucent zirconia restorations: Effects on the antagonist wear and survivability
    (2022-12-01) Alves, Larissa Marcia Martins [UNESP]; Rodrigues, Camila da Silva [UNESP]; Ramos, Nathalia de Carvalho [UNESP]; Buizastrow, Jeff; Campos, Tiago Moreira Bastos; Bottino, Marco Antonio [UNESP]; Zhang, Yu; Melo, Renata Marques de [UNESP]; Universidade Estadual Paulista (UNESP); New York University College of Dentistry; Aeronautics Technological Institute (ITA); University of Pennsylvania
    Objective: To assess potential antagonist wear and survival probability of silica-infiltrated zirconia compared to glass-graded, glazed, and polished zirconia. Methods: Table top restorations made of 3Y-TZP (3Y), 5Y-PSZ (5Y), and lithium disilicate (LD) were bonded onto epoxy resin preparations. Each zirconia was divided into five groups according to the surface treatment: polishing; glaze; polishing-glaze; glass infiltration; and silica infiltration. The LD restorations received a glaze layer. Specimens were subjected to sliding fatigue wear using a steatite antagonist (1.25 ×106 cycles, 200 N). The presence of cracks, fractures, and/or debonding was checked every one/third of the total number of cycles was completed. Roughness, microstructural, Scanning electron microscopy, wear and residual stress analyses were conducted. Kaplan–Meier, Mantel–Cox (log-rank) and ANOVA tests were performed for statistical analyses. Results: The survival probability was different among the groups. Silica infiltration and polishing-glaze led to lower volume loss than glaze and glass-infiltration. Difference was observed for roughness among the zirconia and surface treatment, while lithium disilicate presented similar roughness compared to both glazed zirconia. Scanning electron microscopy revealed the removal of the surface treatment after sliding fatigue wear in all groups. Compressive stress was detected on 3Y surfaces, while tensile stress was observed on 5Y. Significance: 3Y and 5Y zirconia behaved similarly regarding antagonist wear, presenting higher antagonist wear than the glass ceramic. Silica-infiltrated and polished-glazed zirconia produced lower antagonist volume loss than glazed and glass-infiltrated zirconia. Silica-infiltrated 3Y and lithium disilicate restorations were the only groups to show survival probabilities lower than 85%.
  • ItemArtigo
    Influence of the Peek Abutments on Mechanical Behavior of the Internal Connections Single Implant
    (2022-11-01) Matos, Jefferson David Melo de [UNESP]; Lopes, Guilherme da Rocha Scalzer [UNESP]; Queiroz, Daher Antonio; Pereira, André Luiz Jesus; Sinhoreti, Mário Alexandre Coelho; Ramos, Nathália de Carvalho [UNESP]; Lino, Vinicius [UNESP]; de Oliveira, Flavio Rosa [UNESP]; Borges, Alexandre Luiz Souto [UNESP]; Bottino, Marco Antonio [UNESP]; University of Florida (UF Health); Universidade Estadual Paulista (UNESP); The University of Texas Health Science Center at Houston (UTHealth); Aeronautics Technological Institute (ITA); Universidade Estadual de Campinas (UNICAMP); Universidade São Francisco (USF); University of Taubaté (UNITAU)
    The present study aimed to evaluate the biomechanical behavior of PEEK abutments with different heights on single titanium implants. To investigate the implant surface, different tests (scanning electron microscopy, energy-dispersive X-ray, and X-ray diffraction) were adopted. Herein, 20 implants received the 4.5 × 4.0 mm PEEK short abutment (SA) and 20 received the 4.5 × 5.5 mm PEEK long abutment (LA). The abutments were installed using dual-cure resin cement. To determine the fatigue test, two specimens from each group were submitted to the single load fracture test. For this, the samples were submitted to a compressive load of (0.5 mm/min; 30°) in a universal testing machine. For the fatigue test, the samples received 2,000,000 cycles (2 Hz; 30°). The number of cycles and the load test was analyzed by the reliability software SPSS statistics using Kaplan-Meier and Mantel-Cox tests (log-rank) (p < 0.05). The maximum load showed no statistically significant differences (p = 0.189) for the SA group (64.1 kgf) and the LA group (56.5 kgf). The study groups were statistically different regarding the number of cycles (p = 0.022) and fracture strength (p = 0.001). PEEK abutments can be indicated with caution for implant-supported rehabilitation and may be suitable as temporary rehabilitation.
  • ItemArtigo
    Bond Strength between Different Zirconia-Based Ceramics and Resin Cement before and after Aging
    (2022-10-01) Silveira, Marcos Paulo Motta [UNESP]; Ramos, Nathália de Carvalho [UNESP]; Lopes, Guilherme da Rocha Scalzer [UNESP]; Tribst, João Paulo Mendes; Bottino, Marco Antonio [UNESP]; Universidade Estadual Paulista (UNESP); University of Taubaté (UNITAU); The University of Amsterdam and Vrije Universiteit
    The objective of this study was to evaluate the bond strength of different stabilized zirconias with resin cement and evaluate the susceptibility to thermal aging of the adhesive interface. Zirconia discs (Vita Zahnfabrik, Bad Säckingen, Germany) were obtained: 3Y-TZP first generation (translucent), 3Y-TZP third generation (high-translucent), 4Y-PSZ (super-translucent), and 5Y-PSZ (extra-translucent). Each disc had its surface polished with a standardized protocol. The specimens were cleaned and sintered according to the manufacturer’s recommendation (conventionally: ~12 h). However, 3Y-TZP groups were subdivided into subgroups and sintered following the speed sintering process (~80 min). After their sintering shrinkage, the dimensions of the final discs were 12 mm × 2 mm. The specimens were blasted with 50 μm aluminum oxide (1 cm distance, 2 bar pressure, and 2 s/cm²), cleaned, and silanized with an MDP primer. After the surface treatment, a resin cement cylinder was built on the ceramic surface (Ø = 1 mm; h = 2 mm). Half of the specimens of each group were subjected to a microshear bond strength test in a universal testing machine after 24 h of cementation, while the other half were subjected to thermocycling prior to the bond strength test (6000 cycles; 5 °C–55 °C, 30 s for each bath). Bond strength data were submitted to two-way ANOVA and Tukey’s test (95%), as well as Weibull analysis, to determine adhesive reliability. Bond strength was statistically different among the materials, and only 3Y-TZP third generation and 4Y-PSZ were not affected by thermal aging. The speed sintering method was statistically similar to the conventional process for 3Y-TZP first generation. However, 3Y-TZP third generation showed higher immediate bond strength when speed sintered. The Weibull modulus was superior for conventional 3Y-TZP third generation and 4Y-PSZ. In this study, thermal aging caused a degradation of the adhesive interfaces of 3Y-TZP first generation and 5Y-PSZ with the resin cement; however, it did not affect the interfaces of 3Y-TZP third generation and 4Y-PSZ. The speed sintering method did not affect the long-term bond strength with the resin cement. Adhesive reliability was superior for 3Y-TZP third generation and 4Y-PSZ.
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    Effect of Surface-Etching Treatment, Glaze, and the Antagonist on Roughness of a Hybrid Ceramic after Two-Body Wear
    (2022-10-01) Grangeiro, Manassés Tercio Vieira [UNESP]; Rodrigues, Camila da Silva [UNESP]; Rossi, Natália Rivoli [UNESP]; da Silva, Jadson Mathyas Domingos [UNESP]; Ramos, Nathalia de Carvalho [UNESP]; Tribst, João Paulo Mendes [UNESP]; Anami, Lilian Costa [UNESP]; Bottino, Marco Antonio [UNESP]; Universidade Estadual Paulista (UNESP)
    Stains and glaze are effective procedures for achieving an aesthetic smoothness on indirect restorations. Thus, the effect of surface-etching treatments previous to the stain layer and the glaze application on the occlusal and antagonist wear of a hybrid ceramic were evaluated against different antagonists. Disc-shaped samples were prepared from polymer-infiltrated ceramic network (PICN) blocks. The specimens were divided into eight groups, according to the surface-etching treatment and glaze application: P (polished specimens); PG (polishing plus glaze); E (hydrofluoric acid etching plus stain); EG (acid etching plus stain plus glaze); A (aluminum oxide sandblasting plus stain); AG (sandblasting plus stain plus glaze); S (self-etching primer plus stain); SG (self-etching primer plus stain plus glaze). Half of the samples were subjected to a wear simulation with a steatite antagonist, and the other half was tested using a PICN antagonist. The test parameters were: 15 N, 1.7 Hz, 6 mm of horizontal sliding, 5000 cycles. The discs and the antagonists’ masses were measured before and after the wear tests. The average roughness and spacing defects were evaluated. The etching treatment affected the surface and antagonist mass loss when tested against steatite. AG showed the highest mass loss. This influence was not detected when using the PICN antagonist. The glaze application after staining ensures a smoother surface and avoids antagonist wear.
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    Influence of Abutment Design on Biomechanical Behavior to Support a Screw-Retained 3-Unit Fixed Partial Denture
    (2022-09-01) Lopes, Guilherme da Rocha Scalzer [UNESP]; Matos, Jefferson David Melo de [UNESP]; Queiroz, Daher Antonio; Tribst, João Paulo Mendes; Ramos, Nathália de Carvalho [UNESP]; Rocha, Mateus Garcia; Barbosa, Adriano Baldotto; Bottino, Marco Antonio [UNESP]; Borges, Alexandre Luiz Souto [UNESP]; Nishioka, Renato Sussumu [UNESP]; Universidade Estadual Paulista (UNESP); University of Florida (UF Health); The University of Texas Health Science Center at Houston (UTHealth) School of Dentistry; The University of Amsterdam and Vrije Universiteit; Universidade São Francisco (USF); Midwest Dental Arts Inc
    This study aimed to evaluate the biomechanical behavior of Morse taper implants using different abutments (CMN abutment [(CMN Group] and miniconical abutments [MC Group]), indicated to support a screw-retained 3-unit fixed partial denture. For the in vitro test, polyurethane blocks were fabricated for both groups (n = 10) and received three implants in the “offset” configuration and their respective abutments (CMN or MC) with a 3-unit fixed partial denture. Four strain gauges were bonded to the surface of each block. For the finite element analysis, 3D models of both groups were created and exported to the analysis software to perform static structural analysis. All structures were considered homogeneous, isotropic, and elastic. The contacts were considered non-linear with a friction coefficient of 0.3 between metallic structures and considered bonded between the implant and substrate. An axial load of 300 N was applied in three points (A, B, and C) for both methods. The microstrain and the maximum principal stress were considered as analysis criteria. The obtained data were submitted to the Mann–Whitney, Kruskal–Wallis, and Dunn’s multiple comparison test (α = 5%). The results obtained by strain gauge showed no statistical difference (p = 0.879) between the CMN (645.3 ± 309.2 με) and MC (639.3 ± 278.8 με) and allowed the validation of computational models with a difference of 6.3% and 6.4% for the microstrains in the CMN and MC groups, respectively. Similarly, the results presented by the computational models showed no statistical difference (p = 0.932) for the CMN (605.1 ± 358.6 με) and MC (598.7 ± 357.9 με) groups. The study concluded that under favorable conditions the use of CMN or MP abutments to support a fixed partial denture can be indicated.
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    Effect of Porcelain-to-Zirconia Ratio and Bonding Strategy on the Biaxial Flexural Strength and Weibull Characteristics of a Stress-Free Bilayer CAD/CAM Ceramic System
    (2022-01-01) Sato, Tabata Prado [UNESP]; Arata, Anelyse; de Miranda, Larissa Mendonça; Bottino, Marco Antonio [UNESP]; de Melo, Renata Marques [UNESP]; Zhang, Yu; Souza, Rodrigo Othávio Assunção; Universidade Estadual Paulista (UNESP); Federal University of ABC; Division of Prosthodontics; School of Dental Medicine; Federal University of Rio Grande do Norte
    Purpose: To evaluate the biaxial flexural strength of different porcelain-to-zirconia thickness ratios and bonding strategies of a stress-free bilayer CAD/CAM ceramic system. Materials and Methods: A total of 60 zirconia discs (diameter: 15 mm; thickness: 0.3 or 0.5 mm; n = 30 for each thickness) were divided into six groups (n = 10 each) according to porcelain-to-zirconia ratio and bonding strategy: VM/Zr (control): zirconia discs veneered with a feldspathic ceramic (VM 9, Vita) in 0.9-mm and 0.7-mm thicknesses using a conventional hand-layering technique; VB/Zr-SBU: zirconia discs airborne particle–abraded with 50-μm Al2O3 particles followed by an MDP primer application (Single Bond Universal, 3M) and bonded to the porcelain with a resin cement (Panavia F 2.0, Kuraray); and VB/Zr-RC: zirconia discs airborne particle– abraded with 30-μm silica-coated Al2O3 particles and silanized and bonded to the porcelain with the same resin cement. Before cementation, the VB (Vitablocs II) discs were etched with 5% hydrofluoric acid (60 seconds), followed by silane application. The bilayers (thickness = 1.2 mm) were loaded with 750 g while light curing the resin cement. Two porcelain-to-zirconia thickness ratios were evaluated: 0.9: 0.3 mm and 0.7: 0.5 mm. All groups were subjected to 106 mechanical cycles, followed by a biaxial flexural test. Data (MPa) were subjected to two-way analysis of variance (ANOVA), Tukey test (5%), and Weibull analyses. Results: Two-way ANOVA revealed that the factor porcelain-to-zirconia ratio (P =.0556) was not significant; however, the bonding strategy factor was statistically significant. Among the 0.5-mm zirconia groups, the VB/Zr-SBU group presented higher flexural strength (s) than the VM/Zr or VB/Zr-RC groups. Similar results were also found for the 0.3-mm zirconia groups, in which the VB/Zr-SBU group also presented higher strength than the others, which were similar in comparison (Tukey). The Weibull modulus was similar among the groups; however, the characteristic strength was significantly different (P =.000). Conclusion: The zirconia bonding strategy with 50-μm Al2O3 airborne-particle abrasion, followed by a primer application, increases the flexural strength of a stress-free bilayer CAD/CAM ceramic system
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    Effect of staining layer on roughness after progressive wear of monolithic ceramics
    (2023-01-01) de Matos, Jefferson David Melo [UNESP]; da Rocha Scalzer Lopes, Guilherme [UNESP]; Queiroz, Daher Antonio; Campos, Tiago Moreira Bastos; de Carvalho Ramos, Nathalia [UNESP]; Bottino, Marco Antonio [UNESP]; Universidade Estadual Paulista (UNESP); The University of Texas Health Science Center at Houston (UTHealth) School of Dentistry; Aeronautical Technology Institute (ITA)
    Purpose: The aim of this study was to evaluate staining layer behavior applied to high-translucency zirconia (YZHT), feldspathic ceramics (FD), and zirconia-reinforced lithium silicate (ZLS) surfaces against different antagonists. Methods and Materials: Monolithic ceramic discs (n = 120) (ø 12 mm; thickness, 1.2 mm; ISO 6872) were obtained, 30 from YZHT and FD, and 60 from ZLS CAD/CAM blocks (staining layer applied before or after the crystallization procedure). The specimens were divided into 12 subgroups (n = 10) according to the antagonists: steatite, polymer-infiltrated ceramic, or zirconia. Mechanical cycling (1.5 × 104 cycles; 15 N; horizontal displacement, 6 mm; 1.7 Hz) and flexural strength tests (1 mm/min–1000 kg cell) were performed. The differences between final and initial roughnesses (Ra, Rz, and Rsm), the mass loss, and the flexural strength data were individually analyzed by two-way ANOVA and Tukey's test (α = 0.05). Results: The roughnesses of all ceramics did not present a statistically significant difference before wear simulation: Ra (p = 0.3348), Rz (p = 0.5590), and Rsm (p = 0.5330). After the wear simulation, the Ra parameter was not affected by an interaction between ceramic and antagonist (p = 0.595). The Rz and Rsm parameters were affected only by the antagonist pistons (both, p = 0.000). The ceramics used in this study showed statistically significant differences in mass loss after the wear test (p < 0.0001). The additional firing (2 steps) of the ZLS2 led to a higher lost mass quantity. Conclusion: All ceramics presented similar initial roughnesses and similar roughnesses after the wear simulation. The zirconia antagonist showed better performance against ceramics with high crystalline content. Clinical Significance: It is clear that restorative materials must be carefully selected by dental practitioners according to indications, properties, and antagonists. The steatite antagonist, that is, an enamel analog, showed better performance against vitreous ceramics, while the zirconia antagonist showed better performance against ceramics with high crystalline content. Wear affects the surface roughnesses of the ceramics. Additional firing for the staining of the zirconia-reinforced lithium silicate ceramic led to a greater loss of mass.
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    Electrospun PHBV nanofiber containing Tea Tree Oil: physicochemical and antimicrobial activity
    (2023-01-01) dos Santos, Verônica Ribeiro; Vera, Samara Domingues; de Cena, Gabrielle Lupeti; Silva, Adrielle de Paula; Lemes, Ana Paula; da Conceição, Kátia; Tada, Dayane Batista; Borges, Alexandre Luiz Souto [UNESP]; Trichês, Eliandra de Sousa; Universidade Federal de São Paulo (UNIFESP); Universidade Estadual Paulista (UNESP)
    Aiming to produce an antimicrobial dressing for wound healing applications, in this work Tea Tree oil (TTO) was incorporated into PHBV nanofibers by absorption. It was observed increase in the nanofiber diameter due to 5% TTO absorption efficiency, which also led to a 54% decrease in the contact angle. The releasing assay indicates a 6.8% oil release in the first 24 h – being probably the oil deposited at the polymer surface – followed by a minimal release at 48 h. The set of antimicrobial assays performed suggests the incorporation of TTO optimized the antimicrobial activity of the polymer for E. coli and C. albicans, while against S. aureus no significant difference was observed. The MTT assay showed no cytotoxicity of PHBV, but the incubation of L929 fibroblast cells with PHBV-TTO reduced cell viability. Overall, the PHBV nanofibers containing TTO present great potential as an antimicrobial dressing.