The effectiveness of EDTA 17% as a cleaning solution for the fiber post space after filling with cements

Aim: To evaluate the resistance of the union between a glass fiber post and radicular dentine after cleaning the root with 17% EDTA and filling with different endodontic cements. Methods: Forty uniradicular bovine incisors were removed to obtain root lengths of 18 mm. Endodontic treatment was performed on all roots using different filling cements (zinc oxide and eugenol-based, OZE; cement based on epoxy resin, AH) and cleaning solutions (saline, SA or EDTA), which made it possible to obtain four groups: OZESA, OZEEDTA, AHSA and AHEDTA. Subsequently, 12 mm of filling material was removed from the roots, and they were prepared to receive fiber posts luted with resin cement. To execute the mechanical cycles (2x106 cycles, 90 N, 4 Hz), coronal reconstruction was performed with a silicon matrix. The roots were then sliced (2-mm thick) to perform the push-out test. The results were analyzed using analysis of variance (one factor and two factors) and Tukey's test (α=0,05). Results: Bond strength (Mpa) was significantly higher for OZEEDTA (9,18) and AHEDTA (8,70) than for OZESA (6,06) AHSA (8,7). OZEEDTA also presented the highest values in the cervical region (15,18) but was significantly lower in the apical region (2,99). However, AHEDTA had a homogeneous bond strength in all thirds. Conclusion: Regardless of the endodontic cement used, EDTA was used as an irrigating solution, culminating in a higher bond strength between the glass fiber post and dentin

Influence of substrate, cement and aging on the biaxial flexural strength of lithium disilicate / Influência do substrato, cimento e envelhecimento na resistência a flexão biaxial do dissilicato de lítio

Objective: To evaluate the biaxial flexural strength (BFS) of lithium disilicate (L), cemented on different substrates (epoxy resin - E and metal - M) with dual-cure resin cement (Rc) and zinc phosphate cement (Zc), not aged, thermally aged (TC) or thermo-mechanical aged (TC/MC). Material and Methods: Disks of L, E, and M were fabricated, and the cementation was performed according to the following groups: ERc (L+E+Rc); MRc (L+M+Rc); MZc (L+M+Zc); EZc (L+E+Zc). Ten samples from each described group were tested in BFS, ten more samples were subjected to TC (1×104 cycles between 5 ºC and 55 ºC water), and the last 10 samples were subjected to TC/MC (MC: 1.2×106 cycles, 50 N, 3.8 Hz). The BFS test was performed and scanning electron microscopy (SEM) was performed to evaluate the failure mode. The effect of the cementation strategy (cement/substrate) was compared in each aging method and the effect of the aging method was evaluated for each cementation strategy by one-way ANOVA and Tukey post-hoc test (α=0.05). Results: The strength values were highest to M (237.8 ~ 463.9 MPa), in comparison to the E (41.03 ~ 66.76 MPa), despite aging and luting agent. Flexural strength data decreased after TC and TC/MC in groups cemented with Zc, but was stable when cemented with Rc. SEM analysis indicated that failure origins were located at the tensile surface of the L. Conclusion: Lithium disilicate discs cemented to the metallic substrate presented the highest biaxial flexural strength. The cementation with dual-cure resin cement did not decrease BFS after aging (AU)

Objetivo: Avaliar a resistência à flexão biaxial (BFS) do dissilicato de lítio (L), cimentado sobre diferentes substratos (resina epóxi - E e metal - M) com cimento resinoso dual (Rc) e cimento de fosfato de zinco (Zc), não envelhecido, submetido ao envelhecido térmico (TC) ou ao envelhecido térmico-mecânico (TC/MC). Material e Métodos: Foram confeccionados discos de L, E e M, e a cimentação foi realizada de acordo com os seguintes grupos: ERc (L+E+Rc); MRc (L+M+Rc); MZc (L+M+Zc); EZc (L+E+Zc). Dez amostras de cada grupo descrito foram testadas em BFS, mais dez amostras foram submetidas à TC (1×104 ciclos de imersão em água entre 5 ºC e 55 ºC), e as últimas 10 amostras foram submetidas à TC/MC (MC: 1.2 ×106 ciclos, 50 N, 3.8 Hz). Foram realizados os testes de BFS e a microscopia eletrônica de varredura (MEV) para avaliar o modo de falha. O efeito da estratégia de cimentação (cimento/substrato) foi comparado em cada método de envelhecimento e o efeito do método de envelhecimento foi avaliado para cada estratégia de cimentação por ANOVA a um fator e teste post-hoc de Tukey (α=0,05). Resultados: Os valores de resistência foram maiores para M (237.8 ~ 463.9 MPa), em comparação com E (41.03 ~ 66.76 MPa), independentemente do envelhecimento e do agente cimentante utilizado. Os dados de resistência à flexão diminuíram após TC e TC/MC nos grupos cimentados com Zc, mas se mantiveram estáveis quando cimentados com Rc. A análise MEV indicou que a origem das falhas estava localizada na superfície de tração do L. Conclusão: Os discos de dissilicato de lítio cimentados ao substrato metálico apresentaram maior resistência à flexão biaxial. A cimentação com cimento resinoso dual não diminuiu o BFS após o envelhecimento (AU)

Effect of different surface treatments on the micro tensile bond strength to dentin, biaxial flexural strength and roughness of CAD/CAM resin composite and polymer infiltrated ceramic.

OBJECTIVES: To evaluate the biaxial flexural strength (BFS), surface roughness (Ra) and micro tensile bond strength (µTBS) of two CAD/CAM materials after different surface treatments. MATERIALS AND METHODS: For µTBS, 64 human molars were used and 32 blocks of resin composite (RC-Lava Ultimate) and polymer-infiltrated ceramic (PIC -Vita Enamic). The blocks and teeth were distributed into 16 groups according to the factors "surface treatment" (HF: 10% hydrofluoric acid; APA: Al2O3 sandblasting; SC: silicate-Al2O3 sandblasting; MEP: Monobond Etch and Prime) and "thermal cycling" (TC). After cementation, the blocks were sectioned into 1 mm2 bars. Half of the specimens were thermocycled and submitted to µTBS test. For BFS, RC and PIC discs were made and distributed according to the surface treatments and after mechanical cycling, submitted to BFS test. Roughness, EDS, SEM, and Weibull analyses were also performed. Data were analyzed by (1 or 2-way) ANOVA and Tukey test (α = 0.05). RESULTS: For RC, SC and HF after TC showed significantly higher µTBS values. For PIC HF after TC showed higher µTBS than the other groups. For RC, the BFS was higher for MEP than Al2O3 and SC. For PIC, none of the surface treatments influenced BFS. CONCLUSION: The highest µTBS for RC was obtained with SC followed by silanization and for PIC, HF followed by silanization. The RC showed lower strength after Al2O3 blasting. For PIC all surface treatments resulted in similar BFS.

Effect of different surface treatments on the biaxial flexure strength, Weibull characteristics, roughness, and surface topography of bonded CAD/CAM silica-based ceramics.

OBJECTIVE: To investigate the influence of different surface treatments on biaxial flexure strength, roughness, and surface topography of lithium silicate/disilicate-based ceramics. METHODS: 225 discs (∅: 12 mm; 1.2 mm - ISO 6872) were made from three ceramics: IPS e.max CAD (LD - Ivoclar Vivadent), Suprinity (LSS - Vita) and Celtra Duo (LSC - Dentsply). The samples were randomly divided into 5 groups (n = 15): no treatment (C); 10% hydrofluoric acid + silane (HF); sandblasting Al2O3 + silane (SB); silicatization + silane (SC); and self-etching ceramic primer (SEP). After surface treatment, a resin cement layer was applied to the disc surface (RelyX U200, 3M ESPE), mechanical cycled (1.2 × 106 cycles, 50 N, 3.8 Hz) and submitted to biaxial flexural strength test (1 mm/min, 1000 Kgf). Roughness, EDS and SEM were also performed. Data were analyzed by one-way ANOVA, Tukey test (5%) and Weibull. RESULTS: ANOVA revealed that the "surface treatment" factor was significant for all ceramics (p < 0.05). The groups LD-HF (289.30 ± 40) LD-SEP (298. 87 ± 53.29), LSC-HF (195.51 ± 42.12), LSS-HF (269.58 ± 27.07) and LSS-SEP (207.45 ± 28.63) presented significantly higher biaxial flexure strength than respective control groups, except for the LSC-SEP (165.41 ± 33.86), which was statistically similar to the control. The Weibull modulus was significantly higher for the LD-SB, LSC-SC groups. Additionally, the LD-SB, LSC-SC and LSS-HF groups showed higher roughness compared to the other treatments. SIGNIFICANCE: HF etching followed by silanization and self-etching ceramic primer are the most suitable surface treatments for lithium silicate/disilicate-based glass-ceramics.

COVID-19 and Painful Temporomandibular Disorders: what does the dentist need to know? / COVID-19 e Disfunções Temporomandibulares Dolorosas: o que o dentista precisa saber?

ABSTRACT COVID-19 outbreak may lead to major impacts in applied oral sciences. Remarkably, it could be expected that factors associated to pandemic may lead to a greater risk of developing, worsening and perpetuating TMD and its associated risk factors. This non systematic literature review aims to discuss how the COVID-19 pandemic can influence the emergence, maintenance or worsening of TMD worldwide. During epidemics: the number of people whose mental health is affected tends to be greater than the number affected by the infection, and fear increases anxiety and stress levels in healthy individuals; chronic pain patients probably not receipt important treatments; overuse of medications becomes frequent; there are manifestation of unconscious oral parafunctional habits and poor sleep quality. All these facts represent risk factors common to TMD. Dentists should be aware of these issues and adapt their practices to properly diagnose and treat these patients within a multifactorial approach, increasing the quality of life of these individuals.

RESUMO O surto de COVID-19 pode causar grandes impactos nas ciências relacionadas a odontologia. Notavelmente, pode-se esperar que os fatores associados à pandemia possam levar a um maior risco de desenvolver, agravar e perpetuar a DTM e seus fatores associados. Esta revisão não sistemática da literatura tem como objetivo discutir como a pandemia de COVID-19 pode influenciar no surgimento, manutenção ou agravamento da DTM em todo o mundo. Durante as epidemias: o número de pessoas cuja saúde mental é afetada tende a ser maior do que o número afetado pela infecção, e o medo aumenta os níveis de ansiedade e estresse em indivíduos saudáveis; pacientes com dor crônica provavelmente não recebem tratamentos importantes; o uso excessivo de medicamentos torna-se frequente; há manifestação de hábitos parafuncionais orais inconscientes e má qualidade do sono. Todos esses fatos representam fatores de risco comuns à DTM. O dentista deve estar atento a essas questões e adaptar sua prática para diagnosticar e tratar adequadamente esses pacientes dentro de uma abordagem multifatorial, aumentando a qualidade de vida desses indivíduos.

Can different etching protocols change the properties of a hybrid ceramic?

The aim of this study was to evaluate the effects of different concentrations of hydrofluoric acid (HF) and etching times on the flexural strength, roughness, wettability, and type of failure of a hybrid ceramic (VITA ENAMIC). Blocks of the ceramic material were made according to the norms of International Organization for Standardization standard 6872:2015 and randomly divided into 7 groups (n = 13): control (no treatment); surface etching with 5% HF for 30 (HF5-30), 60 (HF5-60), or 90 (HF5-90) seconds; and surface etching with 10% HF for 30 (HF10-30), 60 (HF10-60), or 90 (HF10-90) seconds. The adhesive surface of 10 specimens in each group was cemented with dual-curing resin cement. The specimens were submitted to biaxial flexural tests and fractographic analysis. Surface analyses were carried out using 3 noncemented specimens from each group. The surface roughness was evaluated through optical profilometry and the surface wettability through goniometry (contact angle). The values obtained were analyzed by a Dunnett test followed by 2-way analysis of variance and Tukey test (α = 5%). The flexural test results indicated a statistically significant reduction in the resistance of the ceramic when conditioned with 10% acid (P < 0.01). Etching with HF, at any concentration used for any applied time, significantly modified the ceramic roughness of the experimental groups (P < 0.01). The wettability was also significantly altered in the HF5-90 group and in all HF10 groups (P < 0.01). The higher the concentration of the acid, the lower the wettability of the ceramic (P < 0.01). Based on these results, a 5% HF concentration is best indicated for the surface treatment of VITA ENAMIC.

Effect of repeated firings and staining on the mechanical behavior and composition of lithium disilicate.

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/10min); SC - single-step characterization - crystallization and staining (applied with a thin brush) were performed in a single step with one firing cycle (850°C/10min); and DC - double-step characterization - crystallization firing cycle was performed first (850°C/10min), followed by staining firing cycle (770°C/90s). 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, 5Hz) 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.

Can the silane heat treatment influence the bond durability between resin cements and a dental ceramic? / O tratamento térmico do silano pode influenciar na durabilidade da adesão entre cimento e cerâmica dental?

ABSTRACT Objective Evaluate the influence of silane heat treatment in bond durability between two resin cements and CAD/CAM feldspathic ceramic. Methods 40 feldspathic ceramic blocks were obtained, and were duplicated in microhybrid composite. All ceramic blocks were etched with 10% hydrofluoric acid for 20 s and received application of silane agent. The blocks were randomizedinto eight groups (n=5) according to the surface treatments and luting agents: P- Panavia F; PAg- Panavia F + Aging; HP- Heat Treatment + Panavia F; HPAg- Heat Treatment + Panavia F + Aging; R- RelyX ARC; Rag- RelyX ARC + Aging; HR- Heat Treatment + RelyX ARC; HRAg- Heat Treatment + RelyX ARC + Aging. The heat treatment was performed in furnace at 100 °C for 2 min. All blocks were cemented and cut to obtain samples with adhesive area of 1 mm2. Aging was performed with 10000 thermal cycles. The samples were subjected to microtensile bond strength test. Results The three-way ANOVA test revealed a significant interaction between cement versus heat treatment (p=0.001) and heat treatment versus thermal cycling (p=0.001) indicating that there was a change in bond strength due to surface treatment and aging. Conclusion Therefore, the heat treatment of the silane at 100 ºC for 2 minutes obtained higher values of bond strength between the resin cement and a feldspathic ceramicafter aging.

RESUMO Objetivo Avaliar a influência do tratamento térmico do silano na resistência de união entre dois cimentos resinosos e uma cerâmica feldspática CAD/CAM. Métodos Quarenta blocos cerâmicos foram duplicados em resina micro-híbrida. Todas as cerâmicas foram condicionadas com ácido fluorídrico 10% por 20 s e receberam aplicação do silano. Os blocos foram randomizados em oito grupos (n = 5): P-Panavia F; PAg- Panavia F + Envelhecimento; HP-Tratamento térmico + Panavia F;HPAg-Tratamento térmico + Panavia F + Envelhecimento; R-RelyX ARC; RAg-RelyX ARC; HR-Tratamento térmico + RelyX ARC; HRAg - Tratamento térmico + RelyX ARC + Envelhecimento. O tratamento térmico foi realizado em forno a 100 °C durante2 min. Todos os blocos foram cimentados e cortados para obter amostras para microtração. Foram feitos 10000 ciclos térmicos. As amostras foram submetidas a teste de micro-tração. Resultados O teste ANOVA revelou uma interação significativa entre cimento/tratamento térmico (p=0,001) e tratamento térmico/ciclo térmico (p=0,001). Conclusão Dessa maneira, o tratamentotérmico do silano a 100ºC por 2 minutos foi capaz de aumentar a resistência de união entre o cimento resinoso e uma cerâmica feldspática mesmo após o envelhecimento.

Can the size and the luting material influence in the bond strength of the fiberglass post to dentin? / O comprimento e o tipo de cimento podem influenciar na adesão do pino de fibra de vidro a dentina?

Aim: To evaluate the influence of lengths and different luting agents on the bond strength of fiberglass posts' adhesion to dentin.Methods: Sixty single-root bovine teeth were endodontically treated and included in polyether and acrilyc resin to simulate a periodontal ligament. These were divided into 6 groups according to the post lengths (6, 10 or 14 mm) and luting agents (self-adhesive dual resin cement ­ U; or etch-and-rinse dual resin cement ­ A): U6, U10, U14, A6, A19, and A14. All fiberglass posts were cemented according to manufacturer instructions. After this, mechanical aging was performed (1.2x106 cycles; 4 Hz, 90 N). The push-out specimens were then conducted (2.0 ± 0.1 mm), with the test executed in a universal machine (10 kgf at 0.5 mm/min). Data obtained were submitted to the Kruskal-Wallis and Dunn's test. Results: No statistically significant difference was observed in bond strength between the groups due to the type of luting agent (p > 0.05). However, the isolated post-length factor showed significantly different results for the U groups (p < 0.05). The U10 group showed similar union values to U6 but statistically inferior to U14. Conclusion: bond strength of fiberglass posts of the same length as the dentin presented no differences according to the luting agent, but the post-length property influenced the bond strength when self-adhesive resin cement was used.

Objetivo: avaliar a influência dos agentes cimentantes e dos diferentes comprimentos de pinos na resistência de união de pinos de fibra de vidro a dentina. Métodos: Sessenta dentes bovinos uniradiculares tiveram a raiz endodonticamente tratada, e foram incluídos em poliéter e resina acrílica para simular o ligamento periodontal. Os espécimes foram divididos em seis grupos de acordo com o comprimento dos pinos (6, 10 ou 14mm) e dos agentes de cimentantes (cimento resinoso dual autoadesivo (RelyX U200, 3M ESPE) - U; ou cimento resinoso dual convencional (AllCem Core, FGM) - A: U6, U10, U14, A6, A19 e A14. Todos os pinos de fibra de vidro foram cimentados conforme as recomendações do fabricante. Após, o envelhecimento mecânico (1,2x106 ciclos; 4 Hz, 90 N) as amostras foram fatiadas para o teste de push-out (2,0 ± 0,1 mm) executado em uma máquina de ensaio universal (10 kgf a 0,5 mm/min). Os dados foram submetidos ao teste de Kruskal-Wallis e Dunn. Resultados: não houve diferença estatística na resistência de união entre os grupos devido ao tipo de agente cimentante (p > 0,05), mas houve para o comprimento dos pinos dos grupos U (p < 0,05). O grupo U10 apresentou valores de união semelhantes a U6, mas estatisticamente inferiores ao U14. Conclusão: a resistência de união dos pinos de fibra de vidro de um mesmo comprimento não apresentou diferenças mesmo quando cimentados com cimentos diferentes, mas o comprimento dos pinos isoladamente influenciou quando o cimento resinoso autoadesivo foi utilizado.

Effect of extrinsic pigmentation and surface treatments on biaxial flexure strength after cyclic loading of a translucent ZrO2 ceramic.

OBJECTIVE: To evaluate the influence of extrinsic pigmentation on the biaxial flexural strength and surface topographic of translucent Y-TZP (InCoris TZI - Sirona - USA) subjected to several surface treatments. METHODS: Sintered zirconia discs-shaped specimens (n=120) (ø:12mm; thickness:1.2mm; ISO 6872) were prepared and divided (n=15) according to various factors: "extrinsic pigmentation" (n: without; p: with) and "surface treatments" (C: control - as sintered; A: abraded with silica-coated alumina particles (30µm); G: glazed with a thin film of low-fusing porcelain glaze; GH: glazed and etched with 10% hydrofluoridric acid for 60s. Mechanical cycling (1.2×106 cycles, 200N, 3.8Hz) and flexural strength test (1mm/min - 1000kg cell) were performed. Two-way ANOVA and Tukey's were used for statistical test (α=0.05). Weibull analysis was used to evaluate the strength reliability. Samples were analyzed via (1) an optical profilometer to determine the surface roughness (Ra); (2) an X-ray diffraction (XRD) to evaluate phase transformations; and (3) a SEM equipped with an energy dispersive X-ray spectroscopy (EDX) to elucidate morphological properties and chemical compositions. RESULTS: Regardless of the surface treatment (p=0.5459) (Cn: 560.16MPa; Gn: 573.36MPa; An: 643.51MPa; GHn: 542.94MPa; Cp: 628.04MPa; Gp: 641.90MPa; Ap: 554.47MPa; GHp :602.84MPa) and extrinsic pigmentation (p=0.1280) there was no difference in the flexural strength among the experimental groups. According to the XRD analysis, phase transformations occurred in the An group (t→m) and in Ap group (t→c). Surface roughness was affected by surface treatments (An - p=0.001) and extrinsic pigmentation (Gp - p=0.001). SIGNIFICANCE: The biaxial flexural strength of the tested samples was not affected neither by surface treatments nor by pigmentation, although it can cause phase transformation and promote surface roughness.

Effect of different loading pistons on stress distribution of a CAD/CAM silica-based ceramic: CAD-FEA modeling and fatigue survival analysis.

PURPOSE: This study evaluated the effect of different loading pistons, made of various materials and with different elastic moduli acting as antagonist material, on stress distribution and fatigue behavior of a CAD/CAM silica-based ceramic. MATERIALS AND METHODS: Discs of CAD/CAM made silica-based ceramic (N = 60) (VITA MARK II) were divided into six groups (n = 10 per group), according to the test method (M: Monotonic; F: Fatigue) and the antagonist piston material (T: Tungsten; S: Steel; G: Epoxy resin). FT, FS and FG combinations were submitted to mechanical cycling (2 × 106 cycles, 4 Hz, 45 N). The bending stress after fatigue were also valuated using Weibull analysis and the parameters η (eta), ß (beta) and the mean time to failure (MTTF) were calculated. Fractographic analysis and Finite Element Analysis (FEA) were performed. Data were analyzed using ANOVA and Tukey's tests (alpha=0.05). RESULTS: MG presented significantly less bending strength (MPa) (75.6) compared to MT (87.8) and MS (84.4) (p < 0.05). Six specimens from FT (MMTF: 8.3 × 106; ß:0.60; η:5.6 × 106), four from FS (MMTF: 1.9 × 106; ß:1.2; η:2.0 × 106) and one from FG (MMTF: 1.3 × 106; ß:0.48; η:0.64 × 106) survived the fatigue test. The stress peak on the tensile surface of S was similar to that of T and both were less than that of G. The failure origins were on the tensile surface. CONCLUSION: The epoxy resin pistons were able to decrease the bending stress, and life expectancy (faster failure) of a silica-based ceramic compared to tungsten and steel.

Digital smile designing, pressing and stratifying ceramic lithium disilicate veneers to rehabilitate dental agenesis: a clinical report / Facetas cerâmicas de dissilicato de lítio estratificadas e prensadas para reabilitação de agenesia dental com digital smile design: relato de caso

ABSTRACT This article had the objective of reporting a case of aesthetic rehabilitation with laminated facets from the 14 to the 24 teeth made with IPS E.max Ceram ceramics (Ivoclar-Vivadent), which replaced previous unsatisfactory composite resin restorations in the anterior region. The patient had agenesis of 12 and 22 teeth, making it necessary to anatomize the anterior teeth. A digital smile design was first virtually created and then followed by a diagnostic wax-up. The following was performed in a single day: periodontal surgery using the flapless technique to achieve prosthetic space; teeth preparation; an additionalsilicone impression; and multiple provisional restorations of bis-acryl composite resins were fabricated. Fourteen days later, in the second session the ceramic veneers were etched with 5% hydrofluoric acid for 20s; they received a silane application and a silane heat treatment, then lastly an ultrasonic bath. A universal adhesive was used in combination with a light curing cement.Cementation was performed immediately following an occlusal adjustment. The patient returned for a follow-up appointment another fourteen days after the luting process, in which a further occlusal adjustment was performed, and he reported complete satisfaction with the treatment.

RESUMO Este é um relato de caso de reabilitação estética anterior com facetas laminadas dos elementos 14 ao 24 confeccionadas com a cerâmica IPSE.max Ceram (Ivoclar -Vivadent), as quais substituíram facetas de resina composta insatisfatórias dos elementos 13 ao 23. Ressalta-se que o paciente possuía agenesia dos elementos 12 e 22, tornando-se necessária a reanatomização dos dentesanteriores. Inicialmente ocorreu o planejamento digital, seguido pelo enceramento diagnóstico. Foi realizado em consulta única: cirurgia periodontal pela técnica "flapless" para conquista de espaço protético; confecção dos preparos para facetas; moldagem com silicona de adição; e confecção de múltiplos provisórios em resina bisacrilica. Na consulta de cimentação, as peças foram tratadas comácido fluorídrico 5% por 20s; silanizadas com Relyxceramic primer (3M ESPE), submetidas ao tratamento térmico; e banho ultrassônico. O sistema adesivo utilizado foi o Single Bond (3M ESPE) associado ao RelyxVenner (3M ESPE). Imediatamente a cimentação foi realizado um ajuste oclusal. Após 14 dias o paciente retornou para uma nova consulta de acompanhamento, na qual foi realizada mais um ajuste oclusal, e relatou total satisfação com o tratamento realizado.

Different surface treatment protocols of a Y-TZP ceramic with a superficial glaze layer

Aim: evaluate the influence of etching time with hydrofluoric acid on the bond strength of a Yttrium-stabilized polycrystalline tetragonal zirconia (Y-TZP) ceramic with a superficial glaze layer and a resin cement. Methods: Y-TZP blocks were cut to obtain 40 samples. They were distributed into four groups (n = 10): control treated by sandblasting with silica-coated alumina (RS) and three glazed experimental groups with different etching times: GS20s, GS60s and GS100s. Cementation was done with a universal adhesive and a resin cement. Two cement cylinders were made in each block. After thermocycling, the shear bond test was performed. Two extra samples of each group were made to obtain profilometry, scanning electron microscopy, mapping and backscattered electron detector images. Energy dispersive spectrometry and goniometry were also performed. Results: Kruskal-Wallis and Dunn tests demonstrated bond strength differences only between the RS (22.10MPa) and the GS groups (GS20s: 8,10Mpa; GS60s: 10.49MPa; GS100s: 7.53MPa) (p = 0.001), but there was no difference among the experimental groups (p > 0.05). The contact angles were 55.33º (RS); 70.78° (GS100s); 48.20º (GS60s) and 28.73º (GS20s). ANOVA and Tukey test demonstrated similar wettability of RS to GS60s and GS100s (p > 0.05), but all the experimental groups were statistically different between them (p < 0.001). Qualitative image analysis revealed an irregular glaze distribution after etching. The thickness of the remaining glaze layer measured by profilometry was 5±1µm (GS20S), 4±1µm (GS60S) and 3±1µm (GS100s). Conclusion: The etching time of glazed zirconia did not influence the adhesive strength of the ceramic to the resin cement

Bond and topography evaluation of a Y-TZP ceramic with a superficial low-fusing porcelain glass layer after different hydrofluoric acid etching protocols / Avaliação da adesão e topografia de uma zircônia Y-TZP com uma camada de glaze após diferentes protocolos de condicionamento com ácido fluorídrico

Introduction: Despite being one of the most studied ceramics today, zirconia still does not have a well-defined adhesion protocol. Objective: Evaluate the influence of different etching times and hydrofluoric acid (HF) concentrations on the zirconia surface and bond strength between a vitrified Y-TZP ceramic and a resin cement. Materials and method: The zirconia surface treatments were: sandblasting with silica-coated alumina (Co); glaze application + 5% HF etching for 5s (G5-5s), 10s (G5-10s) or 20s (G5-20s); glaze application + 10% HF etching for 5s (G10-5s), 10 (G10-10s) or 20s (G10-20s) . Then, cement cylinders (3.3 × 3.3 mm) were built up for shear bond test on all specimens. The specimens were subjected to 6000 thermal cycling before the test. Fractures were analyzed by stereomicroscope. Data were statistically analyzed by Kruskal-Wallis and Dunn statistical tests (5%). Extra samples of each group were made to obtain profilometry and scanning electron microscopy (SEM). Result: Zirconia-cement bond strength was affected by the ceramic surface treatments (p = 0.001). G10-5s (2.71 MPa) recorded the highest bond strength values, followed by the Co (2.05 MPa) while G5 groups had the lowest bond value. Adhesive failure of the samples predominated. The image analysis revealed G5 groups seem to have a lower roughness when compared to groups treated by 10% HF. The creation of pores in the low-fusing porcelain glass layer surface occurred only when 10% HF was used. Conclusion: The low-fusing porcelain glass layer application was able to overcome the sandblasting and obtain a greater adhesive bond to the resinous cement, however, only when 10% HF was used for an interval of 5 seconds.

Introdução: Apesar de ser uma das cerâmicas mais estudadas atualmente, a zircônia ainda não possui um protocolo bem definido para uma cimentação adesiva. Objetivo: Avaliar a influência de diferentes tempos de condicionamento e concentrações do ácido fluorídrico (AF) na superfície da zirconia e na resistência de união entre uma cerâmica Y-TZP vitrificada e um cimento resinoso. Material e método: Os tratamentos de superfície foram: jateamento com óxido de alumínio revestido com sílica (Co); aplicação de glaze + condicionamento com AF 5% por 5s (G5-5s), 10s (G5-10s) ou 20s (G5-20s); aplicação de glaze + condicionamento com AF 10% por 5s (G10-5s), 10 (G10-10s) ou 20s (G10-20s). Em seguida, cilindros de cimento (3,3 × 3,3mm) para teste de cisalhamento foram feitos em todos os espécimes. Os espécimes foram submetidos a 6000 ciclos térmicos antes do teste de adesão. As fraturas foram analisadas por estereomicroscópio. Os dados foram analisados ​​estatisticamente por Kruskal-Wallis e Dunn (5%). Amostras extra de cada grupo foram feitas para realização de perfilometria e microscopia eletrônica de varredura (MEV). Resultado: A resistência de união zircônia-cimento foi afetada pelos tratamentos de superfície (p = 0,001). Os grupos G10-5s (2,71 MPa) registraram os maiores valores de resistência de união, seguidos pelos Co (2,05 MPa), enquanto os grupos G5 apresentaram o menor valor de união. Falhas adesivas foram predominantes. As análises por imagem revelaram que os grupos G5 parecem ser menos rugosos quando comparados aos grupos tratados com AF 10%. A criação de poros na superfície vítrea (glaze) ocorreu apenas quando foi utilizado AF 10%. Conclusão: A aplicação de camada de vidro de porcelana de baixa fusão foi capaz de superar o jateamento e obter uma maior adesão adesiva ao cimento resinoso, no entanto, somente quando foi utilizado 10% de HF por um intervalo de 5 segundos.

Can low-fusing glass application affect the marginal misfit and bond strength of Y-TZP crowns?

To evaluate the effect of different surface treatments on the marginal misfit and retentive strength between Y-TZP crowns and an epoxy resin. Forty (40) epoxy resin (G10) abutments (height: 5mm, conicity: 60, finish line: large chamfer) with equal dimensions were milled and included in polyurethane to simulate the periodontal ligament. Next, 40 Y-TZP crowns (thickness: 1mm) were milled (Cerec in Lab) and randomly divided into four groups (n=10) according to the surface treatment: GS(glaze spray), GP(glaze powder/liquid), P(zirconia primer) and RS(tribochemical silica coating). The conditioned surfaces were cemented with dual self-adhesive cement, light cured and submitted to thermomechanical cycling (2x106, 100N, 4Hz, 5°/55°C). Marginal misfit was analyzed by a stereomicroscope and SEM. Retentive strength test was performed (1mm/min) until crown debonding. Glaze layer thickness was also performed to GS and GP groups. Marginal misfit data were analyzed by Kruskal Wallis and Dunn tests; one-way ANOVA and Tukey (5%) analyzed the tensile strength data. The marginal misfit of the GS (48.6±19.9µm) and GP (65.4±42.5µm) were statistically lower than the RS (96±62.9µm) and P (156±113.3µm) (p=0.001). The retentive strength of the GP (470.5±104.1N) and GS (416.8±170.2N) were similar to the P (342.1±109.7N), but statistically higher than those of the RS (208.9±110N). The GS and GP glaze layer was 11.64µm and 9.73µm respectively. Thus, glaze application promoted lower marginal discrepancy and higher retentive strength values than conventional techniques.

Effect of fatigue protocols on flexural strength of lithium disilicate bars with clamped-ends.

The aim of this study was compare the effect of two in vitro ageing protocols to intraoral aging on the flexural strength of a lithium disilicate (LD) ceramic bars with clamped ends. After polishing and crystallization, the both ends of the bars were cemented to a metallic device and subjected to mechanical cycling, thermomechanical cycling, or intraoral ageing. Ten volunteers used an intraoral device - similar to an occlusal splint with a balanced contact condition on the occlusal surface of the ceramic bar - during 8 h night time / 30 days. Both in vitro and intraoral ageing decreased the flexural residual strength of LD, with the lowest values obtained after intraoral ageing. Thus, the in vitro ageing protocols tested in this study revealed to be less deleterious than intraoral ageing of LD.

Can low-fusing glass application affect the marginal misfit and bond strength of Y-TZP crowns?

Abstract To evaluate the effect of different surface treatments on the marginal misfit and retentive strength between Y-TZP crowns and an epoxy resin. Forty (40) epoxy resin (G10) abutments (height: 5mm, conicity: 60, finish line: large chamfer) with equal dimensions were milled and included in polyurethane to simulate the periodontal ligament. Next, 40 Y-TZP crowns (thickness: 1mm) were milled (Cerec in Lab) and randomly divided into four groups (n=10) according to the surface treatment: GS(glaze spray), GP(glaze powder/liquid), P(zirconia primer) and RS(tribochemical silica coating). The conditioned surfaces were cemented with dual self-adhesive cement, light cured and submitted to thermomechanical cycling (2x106, 100N, 4Hz, 5°/55°C). Marginal misfit was analyzed by a stereomicroscope and SEM. Retentive strength test was performed (1mm/min) until crown debonding. Glaze layer thickness was also performed to GS and GP groups. Marginal misfit data were analyzed by Kruskal Wallis and Dunn tests; one-way ANOVA and Tukey (5%) analyzed the tensile strength data. The marginal misfit of the GS (48.6±19.9μm) and GP (65.4±42.5μm) were statistically lower than the RS (96±62.9μm) and P (156±113.3μm) (p=0.001). The retentive strength of the GP (470.5±104.1N) and GS (416.8±170.2N) were similar to the P (342.1±109.7N), but statistically higher than those of the RS (208.9±110N). The GS and GP glaze layer was 11.64μm and 9.73μm respectively. Thus, glaze application promoted lower marginal discrepancy and higher retentive strength values than conventional techniques.

Efeito da quantidade de queimas e caracterização extrínseca no comportamento mecânico e físico do dissilicato de lítio / Effect of the number of firings and extrinsic characterization on the mechanical and physical behavior of lithium disilicate

Essa pesquisa avaliou o comportamento mecânico e físico das repetidas queimas provenientes das técnicas de caracterização extrínseca do dissilicato de lítio (DL). Duzentos e setenta discos de DL foram fabricados de acordo com a ISO 6872/2008 e distribuídos nos diferentes grupos (n=30). Controles (CO), nos quais não foram realizados caracterização extrínseca. Caracterizados nos quais as queimas de cristalização e do glaze foram realizadas em passo único com IPS e.max CAD Crystall e Glaze Paste (Ivoclar Vivadent) (CR). E caracterizados nos quais as cerâmicas foram primeiramente cristalizadas, seguido da aplicação do IPS e.max Ceram Shades e do Glaze Paste (Ivoclar Vivadent) (CE). Cada tipo de caracterização teve suas amostras submetidas a duas, quatro ou seis queimas: COII, COIV, COVI, CRII, CRIV, CRVI, CEII, CEIV e CEVI. Análises de cor e translucidez foram realizadas com espectrofotômetro colorimétrico após as diversas queimas (n=20). Espectroscopia de raios X por dispersão em energia (EDS), difração de raios-X (DRX) e Raman foram utilizadas para análise de elementos químicos. A rugosidade Ra e a nanodureza Vickers também foram aferidas. Testes de flexão biaxial (n = 10, 1000 kgf, 1 mm/min) e de fadiga ­ staircase (n = 20, 5x104 ciclos, 5Hz, tensão inicial ­ 50% e incremento 5% da carga inicial de fadiga) foram realizados. Análises microscópicas da superfície das amostras (estereomicroscopia, mapping e MEV) também foram feitas. ANOVA um fator e Tukey foram os testes estatísticos utilizados (α=0,05). Para o CE e CO6X-2X, os valores de ΔE00 foram demonstrativos de alterações inaceitáveis de cor (ΔE00 > 1,8). Grupo CO demostrou alterações significativas de translucidez (p = 0,02), já para CE (p = 0,09) e CR (p = 0,26) os valores aumentaram significativamente. Os valores Ra indicaram diferenças significativas devido ao tipo de caracterização (p < 0,000) e número de queimas, porém desse último fator somente para os grupos CO (p = 0,001) e CE (p = 0,008). O EDS e o DRX revelaram uma maior quantidade de conteúdo amorfo para CE e CR. Os valores de nanodureza dentre os grupos testados foram estatisticamente similares. O fator quantidade de queimas não foi capaz de influenciar a resistência máxima das cerâmicas, no entanto, o tipo de caracterização reduziu significativamente essa propriedade mecânica (p = 0,001). A fadiga reduziu a resistência do DL em todos os grupos, mas os grupos CR mantiveram resistência semelhantes (CRII e CRIV) ou até superiores (CRVI) aos grupos controles. As interfaces entre material utilizado para caracterização e o DL mostraram apenas sobreposição de materiais para os grupos CE, já para os CR sugere-se que a maquiagem consegue se inter-relacionar com a cerâmica(AU)

The objective of this research was to evaluate the mechanical and physical behavior of repeated firings from the aesthetic characterization of lithium disilicate (LD). Two hundred and seventy LD discs were manufactured according to ISO 6872/2008 and distributed in different groups (n = 30): controls (CO), in which no aesthetic characterization was made; characterized in which the crystallization and glaze firings were performed in a single step with IPS e.max CAD Crystall and Glaze Paste (Ivoclar Vivadent) (CR); and characterized in which the ceramics were first crystallized, followed by the IPS e.max Ceram Shade and Glaze Paste (Ivoclar Vivadent) application (CE). Each type of characterization had samples submitted to two, four or six firings: COII, COIV, COVI, CRII, CRIV, CRVI, CEII, CEIV and CEVI. Color and translucency analyzes were performed with a colorimetric spectrophotometer after the burnings (n = 20). X-ray dispersive energy spectroscopy (EDS), X-ray diffraction (XRD) and Raman spectroscopy were used to analyze chemical elements. Roughness (Ra) and Vickers nano-hardness were also measured. Biaxial flexion tests (n = 10, 1000 kgf, 1 mm/min) and fatigue - staircase (n = 20, 5x104 cycles, 5 Hz, initial tension - 50% and 5% increment of initial fatigue load) . Microscopic analysis of sample surfaces (stereomicroscopy, mapping and scanning electron microscope - SEM) were also performed. One-way ANOVA and Tukey were the statistical tests used (α = 0.05). For CE and CO6X-2X, values of ΔE00 were demonstrative of unacceptable color changes (ΔE00> 1.8). Group CO showed significant changes of translucency (p = 0.02); for CE (p = 0.09) and CR (p = 0.26) the values increased significantly. The values of nano-hardness among the nine groups were statistically similar (p> 0.05). However, Ra values indicated significant differences due to the type of characterization (p < 0.01) and number of firings, but this last factor affected only the CO and CE (p < 0.01) groups. EDS and DRX revealed a greater amount of amorphous content for EC and CR. The number of firings was not able to influence the maximum strength of the ceramics, however, the characterization type significantly reduced this mechanical property (p = 0.001). Fatigue reduced LD strength in all groups, but CR groups maintained similar values (CRII and CRIV) or even higher (CRVI) that the control groups. The interfaces between the material used for characterization and the DL showed only an overlap of materials for the CE groups, whereas for the CR it is suggested that this aesthetic characterization can interrelate with the LD ceramics(AU)

Influence of indirect reinforcements on the flexural strength of a thermally activated acrylic resin used for complete dentures / Influência de reforços indiretos na resistência a flexão de uma resina acrílica ativada térmicamente utilizada na confecção de próteses totais

Objective: This research aimed to verify the performance of thermally activated acrylic resin (TAAR) combined with a mix of glass and aramid fibers and/or composite resin of indirect use by a tree point bending test. Material and Methods: Ten samples, with 65 x 10 x 2.5 mm, were prepared for each group (n = 10): CO, control of only TAAR; CR, in which an 60 mm indirect composite resin was polymerized together with the acrylic resin during the thermo-polymerization cycle; SS, in which ceramic glass mixed with aramid fibers cut 60 mm in length were incorporated into the samples; and SC, in which the same fibers were incorporated with addiction of the indirect composite resin. A three point flexural strength test was performed with a universal testing machine with a load of 50KgF at a speed of 5 mm/min in the center of the samples supported by a suitable device. The reinforced face was placed to the tensile side. The statistical one way ANOVA and Tukey tests were made with a significance level of 95%. Results: The mean value for the CO was 60,27 ± 24,18 MPa, for CR it was 38,39±12,75 MPa, for SS it was 79,97±12,75 Mpa and for CS it was 32,40±9,05 MPa. Conclusion: The use of glass and aramid fibers at the base of a TAAR increased the three-point flexural strength, however when indirect composite resin was incorporated, a significant drop of this mechanical property was observed. (AU)

Objetivo: Esta pesquisa teve como objetivo verificar o desempenho de uma resina acrílica ativada termicamente (RAAT) combinada com uma mistura de fibras de vidro e aramida e / ou resina composta de uso indireto por um teste de flexão de três pontos. Material e Métodos: Foram preparadas dez amostras, com 65 x 10 x 2,5 mm, para cada grupo (n = 10): CO, controle com apenas RAAT; CR, em que uma resina composta indireta de 60 mm com polimerizada em conjunto com a resina acrílica durante o ciclo de termopolimerização; SS, em que o vidro cerâmico misturado com fibras de aramida cortadas com 60 mm de comprimento foi incorporado nas amostras; e SC, nas quais as mesmas fibras foram incorporadas em conjunto com a resina composta indireta. O teste de resistência à flexão de três pontos foi realizado em uma máquina de teste universal com uma carga de 50 KgF a uma velocidade de 5 mm/min no centro das amostras suportadas por um dispositivo adequado. A face reforçado foi colocado no lado da tração. Os testes estatísticos one-way ANOVA e Tukey foram feitos com um nível de significância de 95%. Resultados: O valor para o CO foi de 60,27 ± 24,18 MPa, para CR foi de 38,39 ± 12,75 MPa, para SS foi de 79,97 ± 12,75 Mpa e para CS foi de 32, 40 ± 9,05 MPa. Conclusão: o uso de fibras de vidro e aramida na base de uma RAAT aumentou a resistência à flexão de três pontos, no entanto, quando a resina composta indireta foi incorporada, observou-se uma queda significativa dessa propriedade mecânica (AU)

Efeito de três protocolos de irrigação final na remoção da smear layer do terço médio de dentes endodonticamente tratados: uma análise qualitativa / Effect of three final irrigation protocols on the smear layer removal from the middle third of endodontically treated teeth: a qualitative analysis

Objetivo: avaliar, por meio de microscopia eletrônica de varredura (MEV), a capacidade de desobliteração dos túbulos dentinários de dentes endodonticamente tratados, utilizando- se diferentes soluções quelantes. Métodos: os condutos radiculares de caninos permanentes foram irrigados com hipoclorito de sódio (NaOCl) a 2,5% (substituído a cada instrumento) e obturados. Após a desinfecção e obturação desses dentes, realizou-se a remoção do material obturador, com brocas largo, e utilizou-se as seguintes soluções auxiliares, com irrigação ultrassônica passiva (PUI) por 1 minuto: álcool 70% (controle); ácido cítrico a 10%; EDTA a 17%; e quitosana a 0,2%. As raízes foram seccionadas longitudinalmente em duas partes e as amostras foram levadas para análise em microscópio eletrônico de varredura, para obtenção de fotomicrografias para a avaliação qualitativa. Resultados: as soluções de EDTA a 17% e ácido cítrico a 10% removeram a smear layer de forma semelhante entre si. A solução de quitosana a 0,2% removeu a smear layer parcialmente, apresentando menor eficácia na desobliteração dos túbulos dentinários do que as soluções de EDTA a 17% e ácido cítrico a 10%. Conclusão: houve uma maior remoção de smear layer e desobliteração quando da utilização do EDTA a 17%, seguido do ácido cítrico a 10%, da quitosana a 0,2% e do álcool 70%.