Characterizing ceramics and the interfacial adhesion to resin: I - The relationship of microstructure, composition, properties and fractography

O apelo das cerâmicas como materiais odontológicos é baseado no seu peso leve, dureza alta, inércia química e características tribológicas únicas. Um dos maiores objetivos atuais das pesquisas com cerâmicas é a produção de materiais resistentes que possam oferecer uma utilização confiável para o uso odontológico. A quantificação dos parâmetros microestruturais é importante para o desenvolvimento da relação entre estrutura e propriedades. A análise quantitative da microestrutura fornece uma associação entre a composição, as propriedades físicas, e as características estruturais dos materiais. A confiabilidade estrutural das cerâmicas odontológicas é um fator importante para o sucesso clínico das restaurações cerâmicas. Distribuições complexas de estresse estão presentes na maioria das situações clínicas e, por isso, os valores isolados de resistência não podem ser diretamente extrapolados para prever a durabilidade estrutural dos materiais.The appeal of ceramics as structural dental materials is based on their light weight, high hardness values, chemical inertness, and anticipated unique tribological characteristics. A major goal of current ceramic research and development is to produce tough, strong ceramics that can provide reliable performance in dental applications. Quantifying microstructural parameters is important to develop structure/property relationships. Quantitative microstructural analysis provides an association among the constitution, physical properties, and structural characteristics of materials. Structural reliability of dental ceramics is a major factor in the clinical success of ceramic restorations. Complex stress distributions are present in most practical conditions and strength data alone cannot be directly extrapolated to predict structural performance

Characterizing ceramics and the interfacial adhesion to resin: II- the relationship of surface treatment, bond strength, interfacial toughness and fractography

O sucesso clínico de procedimentos adesivos para restaurações cerâmicas e reparo destas restaurações depende da qualidade e durabilidade da adesão entre a cerâmica e a resina. A qualidade desta adesão dependerá dos mecanismos adesivos que são controlados em parte pelo tratamento de superfície que promove uma união micro-mecânica e/ou química com o substrato. O objetivo desta revisão é correlacionar a tenacidade de fratura aparente da interface adesiva (K A) com os parâmetros morfológicos da superfície de fratura de sistemas cerâmica-resina em função do tratamento da superfície cerâmica. Esta análise é desenvolvida para identificar os mecanismos que promovem a adesão nestes sistemas cerâmica-resina e uma metodologia apropriada para testar a resistência adesiva produzindo resultados relevantes da performa adesiva.The clinical success of resin bonding procedures for indirect ceramic restorations and ceramic repairs depends on the quality and durability of the bond between the ceramic and the resin. The quality of this bond will depend upon the bonding mechanisms that are controlled in part by the surface treatment that promote micromechanical and/or chemical bonding to the substrate. The objective of this review is to correlate interfacial toughness (K A) with fracture surface morphological parameters of the dental ceramic-resin systems as a function of ceramic surface treatment. This analysis is designed to identify mechanisms that promote adhesion of these ceramic-resin systems and an appropriate bond test method to yield relevant adhesion performance data

Adesão a uma cerâmica aluminizada densamente sinterizada e a uma cerâmica a base de alumina / zircônia infiltrada de vidro

The objective of this study was to test two hypotheses: (1) silica coating affects the bond strength between ceramics and a resin cement; (2) bond strength is affected by the type of ceramic. Twelve blocks 5 x 6 x 8 mm of In-Ceram Zirconia (ZR) and twelve Procera AllCeram (PR) ceramics were made and duplicated in composite. Five blocks of each ceramic were treated as follows: (1) ZR + GB (laboratorial airborne particles abrasion with Al2O3 particles) + silane; (2) ZR + SC (chairside tribochemical silica coating system, Cojet); (3) PR + GB; (4) PR + SC. Two treated samples of ceramic were analyzed under SEM. The ceramic-composite blocks were cemented with Panavia F and stored in 37ºC distilled water for 7 days. They were then cut to produce bar specimens (n=30) with a bonding area of 0.6±0.1mm². Specimens were loaded to failure under tension in a universal testing machine (1 mm/min). Bond strength (sigma) values were statistically analyzed using ANOVA (Two-way) and Tukey (alpha = 0.05). Mean sigma (MPa) and standard deviation were as follows: 1) 15.1 ± 5.3; 2) 26.8 ± 7.4; 3) 12.7 ± 2.6; 4) 18.5 ± 4.7. Silica coated surfaces showed statistically higher sigma than the same substrate treated with GB only. In addition, ZR (with vitreous phase) showed higher ó than PR (without vitreous phase).O objetivo deste estudo foi testar duas hipóteses: (1) a deposição de sílica afeta a resistência adesiva entre cerâmicas e cimento resinoso; (2) a resistência adesiva é afetada pelo tipo de cerâmica. Dez blocos (5 x 6 x 8 mm³) das cerâmicas In-Ceram Zircônia (ZR) e Procera AllCeram (PR) foram confeccionados e duplicados em resina composta. Cinco blocos de cada cerâmica foram assim tratados: (1) ZR + GB (jateamento com partículas de Al2O3) + silano; (2) ZR + SC (deposição de sílica/silanização - Sistema CoJet); (3) PR + GB; (4) PR + SC. Os blocos de cerâmica-compósito foram cimentados com Panavia F e armazenados em água destilada (37ºC / 7 dias). Eles foram então cortados para obter corpos-de-prova em forma de barras (n=30) com uma área adesiva de 0,6 ± 0,1mm². Os cp foram submetidos ao teste de microtração em uma máquina de ensaio universal (1mm.min-1). Os valores de resistência adesiva (sigma) foram submetidos à análise de variância (2 fatores) e ao teste de Tukey (alfa = 0,05). As médias de sigma (MPa) e os desvios padrão foram: 1) 15,1 (5,3); 2) 26,8 (7,4); 3) 12,7 (2,6); 4) 18,5 (4,7). A deposição de sílica na superfície cerâmica apresentou maior que o mesmo substrato tratado com GB. Além disso, ZR (com fase vítrea) apresentou maior sigma que PR (sem fase vítrea)

Bonding to densely sintered alumina- and glass infiltrated aluminum / zirconium-based ceramics.

The objective of this study was to test two hypotheses: (1) silica coating affects the bond strength between ceramics and a resin cement; (2) bond strength is affected by the type of ceramic. Twelve blocks 5 x 6 x 8 mm of In-Ceram Zirconia (ZR) and twelve Procera AllCeram (PR) ceramics were made and duplicated in composite. Five blocks of each ceramic were treated as follows: (1) ZR + GB (laboratorial airborne particles abrasion with Al2O3 particles) + silane; (2) ZR + SC (chairside tribochemical silica coating system, Cojet); (3) PR + GB; (4) PR + SC. Two treated samples of ceramic were analyzed under SEM. The ceramic-composite blocks were cemented with Panavia F and stored in 37ºC distilled water for 7 days. They were then cut to produce bar specimens (n=30) with a bonding area of 0.6±0.1mm². Specimens were loaded to failure under tension in a universal testing machine (1 mm/min). Bond strength (sigma) values were statistically analyzed using ANOVA (Two-way) and Tukey (alpha = 0.05). Mean sigma (MPa) and standard deviation were as follows: 1) 15.1 ± 5.3; 2) 26.8 ± 7.4; 3) 12.7 ± 2.6; 4) 18.5 ± 4.7. Silica coated surfaces showed statistically higher sigma than the same substrate treated with GB only. In addition, ZR (with vitreous phase) showed higher ó than PR (without vitreous phase)

Color and optical properties of 3D printing restorative polymer-based materials: A scoping review

Objective: Color and optical properties are particularly crucial to mimic natural tooth. This scoping review aimed to present an overview of the literature published on color and optical properties of 3D printing restorative polymer-based materials. The litera- ture search was performed in MED-LINE/Pubmed, Scopus and Web of Science. Materials and methods: The literature search was conducted in the three databases based on the question: “Are the optical properties and color adequately reported on polymer-based 3D printing dental restorative materials studies?” with no restriction on year of publication. Data were reported and synthesized following PRISMA-ScR statement. Results: Nine studies fit the inclusion criteria. Five studies focused on evaluating only color stability; three articles assessed the color stability along with mechanical and morphological properties and only one study compared color parameters of 3D printed to conventional polymers. Two studies evaluated translucency parameter and no study was found evaluating scattering, absorption, and transmittance. Conclusions: Color and optical properties of 3D printed polymers that can be used in restorative dentistry are not adequately evaluated and characterized. Future studies on the influence of experimental printing conditions should include these physical properties to assist on improving esthetics. Clinical significance: This review shows the scarce literature existing on color and optical properties of 3D printing restorative polymer-based materials. These proper- ties and their study are of outmost importance to create materials that mimic natural tooth to allow clinicians to obtain esthetically pleasant restorations.i + D + I Government of Andalusia 2020, Spain (P20-00200)University of Granada, Spain (A.TEP.280. UGR18)Spanish Ministry of Science, Innovation and Universities (PGC2018-101904-A-100)State of Rio Grande do Sul, FAPERGS (grant#19/2551-0001721-9)

Influência de diferentes métodos de ampliação cervical na determinação do comprimento de trabalho

OBJETIVO: determinar a influência de três sistemas distintos de instrumentos rotatórios para alargamento cervical na determinação do comprimento real de trabalho. MATERIAL E MÉTODOS: Trinta primeiros molares inferiores foram submetidos ao acesso endodôntico convencional e odontometria inicial pelo método visual, utilizando-se para irrigação/aspiração da câmara pulpar o hipoclorito de sódio a 5%. Procedeu-se a ampliação cervical dos canais mésio-vestibulares empregando-se diferentes alargadores cervicais. De acordo com o sistema de ampliação cervical empregado, as 30 amostras foram divididas aleatoriamente em 3 grupos de 10 dentes cada. No Grupo 1 as brocas de Gates-Glidden foram utilizadas para a ampliação cervical; no Grupo 2, Orifice Openers foram empregados; e, no Grupo 3, foi usado o sistema La Axxess. Foram utilizadas em ordem crescente, duas numerações do sistema rotatório correspondente a cada grupo e, após, realizou-se a odontometria final. A leitura das duas tomadas odontométricas foi realizada com paquímetro digital, em milímetros, considerando-se duas casas decimais para averiguar a provável discrepância entre ambas as tomadas. RESULTADOS: a análise de variância (ANOVA) e o teste de Tukey (p£ 0,05) demonstraram diferença estatística entre o Grupo 1 e os Grupos 2 e 3. CONCLUSÕES: todos os grupos apresentaram encurtamento do comprimento de trabalho após alargamento cervical; os grupos preparados com instrumentos La Axxes e Orifice Opener apresentaram os melhores resultados.OBJECTIVE: to investigate the influence of three different rotary systems for cervical flaring on establishment of the real working length. MATERIAL AND METHODS: Thirty mandibular first molars were submitted to conventional endodontic access and initial working length measurement, followed by irrigation/suction of the pulp chamber with 5% sodium hypochlorite. Teeth were randomly divided into 3 groups (n=10) and cervical flaring of the mesiobuccal canals were performed using one of the following instrument systems: Group 1 - Gates-Glidden burs; Group 2 - Orifice Openers; Group 3 - La Axxess system. Two subsequent numbers of instruments of each rotary system were used and the final working length was recorded. A digital calyper was used to record the working length, in millimeters, to investigate a possible discrepancy between initial and final measurements. RESULTS: Analysis of variance (Anova) na Tukey test revealed statistical difference between Group 1 and Groups 2 and 3 (p£ 0.05). CONCLUSIONS: all groups presented shorter working length after cervical flaring; groups prepared with instruments La Axxes and Orifice Opener presented the best results among the systems studied

The influence of printing angle on color and translucency of 3D printed resins for dental restorations

Objectives: To evaluate the influence of printing orientation on color and translucency of 3D printing restorative resins. Methods: Four 3D printing resin systems in the available shades (DFT-Detax Freeprint Temp- A1, A2,A3; FPFormlabs Permanent Crown- A2,A3,B1,C2; FT- Formlabs Temporary CB- A2,A3,B1,C2; GCT-GC TemporaryLight, Medium) were evaluated. Three samples (10x10x1.2 mm) from each material were printed at two different printing orientations (0 degrees and 90 degrees) and polished to 1.00 +/- 0,01 mm of thickness. Spectral reflectance was measured against black background using a calibrated spectroradiometer, CIE D65 standard illuminant and the 45 degrees/0 degrees geometry. Color and translucency differences were evaluated using CIEDE2000 metric (AE00) and 50:50% perceptibility (PT00 and TPT00) and acceptability (AT00 and TAT00) thresholds. Results: In general, color changes due to printing orientation at (0 degrees and 90 degrees) were mainly produced by AL* or AC* . AE00 were above PT00 for all DFT shades, FP-B1, FP-C2, FT-A2 and FT-B1. Only for DFT-1, AE00 was above AT00. ARTP00 values were above TPT00 for DFT-A1, DFT-A3, FP-B1 and FT-B1, but lower than TAT00. The direction of the changes in translucency (ARTP00) depends on the material and shade. Significance: The selection of building orientation (0 degrees and 90 degrees) for the 3D printed resins influence the visual color and translucency and therefore their esthetic appearance. These aspects should be considered when printing dental restorations using the evaluated materials.FEDER/Government of Andalusia P20-00200Spanish Government PGC2018-101904-A-100State of Rio Grande do Sul, FAPERGS 19/2551-0001721-9Universidad de Granada/CBU

Optical behavior of 3D-printed dental restorative resins: Influence of thickness and printing angle

The authors also acknowledge Detax GmbH, Formlabs Inc. and GC Corporation for providing the polymer-based 3D printing restorative resins used in this study.Objectives To evaluate the influence of thickness and printing angle on the optical properties of 3D-printed dental restorative resins. Methods Four 3D printing resin systems were evaluated: DFT-Detax Freeprint Temp; FP- Formlabs Permanent Crown; FP- Formlabs Temporary CB; and GCT- GC Temporary-. Samples from each material were printed at 0° and 90°, and polished up to 0.5, 1.0, 1.5 and 2.0 mm thickness. Scattering (S), absorption (K) and albedo (a) coefficients, transmittance (T%), light reflectivity (RI) and infinite optical thickness ( ) were calculated using Kubelka-Munk’s model. Data were statistically analyzed using Kruskal–Wallis¸ Mann-Whitney tests, and VAF coefficient. Results The spectral distribution on S, K, T%, RI, were wavelength dependent. Although the spectral behaviors were similar for all the specimens evaluated, the values of S, K, T% and presented significant differences between specimen thicknesses for all the materials used and for both printing orientations. Values for S and K increased, and T% and decreased. Significant differences between 0° and 90° were found for RI values at 0.5 and 1.0 mm thick samples, for S and K at 2.0 mm, for at 0.5 and 1.0 mm for DFT, and at 0.5 mm for FT. Conclusions Optical properties of 3D-printed restorative resins vary between thicknesses, and could be affected by the building orientation. Therefore, these factors should be considered in order to improve the biomimetic potential of 3D-printed dental restorative resins. Clinical significance Understanding the optical behavior of the 3D-printed restorative resins is essential to optimize their clinical performance.FEDER/ Government of Andalusia P20-00200support from the FEDER/ Government of Andalusia P20-00200 and State of Rio Grande do Sul, FAPERGS (grant #19/2551-0001721-9)Funding for open access charge: Universidad de Granada / CBU

Surface roughness of glazed feldspar, alumina, and zirconia-based ceramics

The aim of this study was to compare the mean surface roughness (Ra) of feldspar-, alumina-, and zirconia-based ceramics, testing the hypothesis that the feldspathic ceramics have lower average surface roughness (Ra) than the ceramics used for infrastructure. Eight disk specimens (5mm in diameter; 2mm in thickness) of each ceramic material were fabricated according to the manufacturer's specifi cations: V7-feldspathic veneer ceramic (Vita VM7); VA-feldspathic veneer ceramic (Vitadur-α); IA-slip casted, glass-infi ltrated alumina-based ceramic (Vita In-Ceram Alumina); IZS-slip casted, glass-infi ltrated zirconia-reinforced alumina-based ceramic (Vita In-Ceram Zirconia); IZB-dry-pressed block ofglass-infi ltrated zirconia-reinforced alumina-based ceramic (Vita In-Ceram Zirconia 2000 for Cerec InLab). All materials were glazed as recommended by the manufacturer. Four Ra readings (Mitutoyo SJ 400) per specimen were performed, averaging the value per specimen (n=8). Ra values were statistically analyzed using one-way ANOVA and Tukey test (α=0.05). V7 showed the lowest mean Ra value (0.43±0.07 μm) compared to the other ceramics. There were no statistical differences between the mean Ra values of VA (0.94±0.2 μm), IA (0.7±0.13 μm), IZS (0.98±0.3 μm) and IZB (0.75±0.4 μm). The testing hypothesis was partially accepted. V7 showed a smoother ceramic surface than the VA. There were no statistically differences between the mean Ra value of the high crystalline content ceramics (IA, IZS, IZB)

Reabilitação estética em dente anterior traumatizado - Relato de Caso

Os dentes anteriores, principalmente os superiores são fundamentais para obtenção de um sorriso estético. Porém, os mesmos são os mais comumente acometidos em casos de fraturas coronárias, que são emergências frequentes na clínica odontológica. Além dos traumatismos dentais acidentais, vários fatores predispõem tais fraturas, como a presença de sobremordida, dentes fragilizados por amplas restaurações, lesões de cárie extensa além de dentes tratados endodonticamente. Em fraturas sem comprometimento pulpar, sempre que possível realiza-se a colagem do fragmento, porém quando este não estiver presente, uma segunda opção é a restauração com resinas compostas de uso direto, que permite resultados estéticos satisfatórios. O objetivo do presente trabalho é descrever um caso clínico de fratura coronária onde optou-se pela restauração com resina composta microhíbrida da parte fraturada. Conclusivamente a metodologia de restaurar dentes através de compósitos restauradores, quando da inviabilidade de uma colagem autógena ou homógena, passa a ser uma opção restauradora de grande importância nos casos de dentes traumatizados