Characteristics of the bonding to yttrium-stabilized tetragonal zirconia polycrystal ceramics

Orientadores: Giselle Maria Marchi Baron, Marcelo GianniniTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: Cerâmicas de zircônia tetragonal policristalina contendo ítrio (Y-TZP) apresentam propriedades mecânicas superiores as das demais cerâmicas odontológicas. No entanto, a técnica de cimentação mais adequada a estes materiais ainda não foi determinada. Os objetivos deste estudo foram: 1) Revisar a literatura a respeito de cerâmicas Y-TZP e seu uso em odontologia; 2) Avaliar o efeito de diferentes intensidades de energia do laser de Er:YAG e do jateamento com partículas de Al2O3 na rugosidade superficial e nas características morfológicas de cerâmicas Y-TZP e 3) Investigar a influência de diferentes tratamentos de superfície e primers para metal na resistência de união de dois cimentos resinosos a cerâmica Y-TZP. A análise da rugosidade superficial e das características morfológicas foi realizada em duas cerâmicas Y-TZP: Cercon Smart Ceramics e Procera Zirconia. Trinta placas de cada cerâmica foram separadas em cinco grupos experimentais de acordo com o tratamento de superfície recebido [nenhum tratamento (Controle), jateamento com partículas de Al2O3 ou irradiação com laser de Er:YAG em diferentes intensidades de energia (200mJ, 400mJ ou 600mJ)]. Após o respectivo tratamento superficial, as placas foram cobertas com ouro e a rugosidade superficial média (Ra, mm) foi mensurada em microscopia confocal. Características morfológicas das superfícies foramobservadas em microscopia óptica e eletrônica de varredura. Os resultados demonstraram que a irradiação com laser nas intensidades de 400mJ e 600mJ promoveu aumento acentuado da rugosidade superficial, além da formação de fendas, perda de massa e alteração de cor. A irradiação com 200mJ de intensidade e o jateamento com partículas de Al2O3 resultaram em alterações superficiais menos agressivas que as altas intensidades do laser. Para a análise da resistência de união, 240 placas de cerâmica (Cercon SmartCeramics) e 240 fragmentos de dentina com extremidade recortada em formato cilíndrico (0,8mm de diâmetro) foram distribuídos em 24 grupos (n=10) de acordo com a combinação entre tratamento de superfície (nenhum, jateamento com partículas de Al2O3 ou irradiação com laser de Er:YAG utilizando 200mJ como intensidade de energia), primer para metal (nenhum, Alloy Primer, Metal Primer II ou Metaltite) e cimento resinoso (Panavia F2.0 ou Calibra). Fragmentos de dentina foram cimentados nas placas de cerâmica, os corpos- eprova foram fixados ao aparato de microcisalhamento e o ensaio foi realizado com velocidade de 1mm/min até a fratura. O jateamento com partículas de Al2O3 resultou em maior resistência de união para ambos os cimentos resinosos. Comparado ao Panavia F2.0, o cimento Calibra apresentou maior resistência de união nos grupos jateados e irradiados. Os dois cimentos demonstraram comportamento semelhante nos grupos sem tratamento de superfície. Os três primers para metal apresentaram resultados semelhantes entre si, independentemente do tratamento da superfície e do cimento resinoso, e a resistência de união da interface cerâmica-dente aumentou com a sua utilização. Pode-se concluir que, apesar da irradiação com 200mJ de intensidade promover alterações superficiais na cerâmica Y-TZP, apenas associação do jateamento com partículas de Al2O3 com a aplicação de primers para metal constitui numa técnica efetiva para união de cimentos resinosos a estas cerâmicasAbstract: Yttrium-stabilized tetragonal zirconia polycrystal (Y-TZP) ceramics present superior mechanical properties compared to other dental ceramics. However, the most adequate luting technique for these materials is unknown. The aims of this study were: 1) To review the literature regarding Y-TZP ceramics and their dental application; 2) To evaluate the effect of different energy intensities of the Er:YAG laser and of air abrasion with Al2O3 particles on the surface roughness and morphologic characteristics of Y-TZP ceramics, and 2) To investigate the influence of different surface treatments and metal primers on the bond strength of two resin cements to a Y-TZP ceramic. The surface roughness and morphologic features were tested in two Y-TZP ceramics: Cercon Smart Ceramics and Procera Zirconia. Thirty plates from each ceramic material were allocated into five groups according to the surface treatment received [none (control), air abrasion with Al2O3 particles or irradiation with Er:YAG laser with three different energy intensities (200mJ, 400mJ or 600mJ)]. After the respective surface treatment, ceramic plates were gold-coated and their mean surface roughness (Ra, mm) was measured using confocal microscopy. Morphological characteristics were examined through optical and scanning electron microscopy. Results demonstrated that irradiation with 400mJ or 600mJ increased surface roughness and created cracks, loss of mass and colour changes on ceramic surfaces. Irradiation with 200mJ and air abrasion with Al2O3 particles provide surface alterations less aggressive than the ones caused by higher intensities of the laser. For the bond strength evaluation, 240 plates of ceramic (Cercon Smart Ceramics) and 240 fragments of dentin trimmed into a cylindrical shape (0.8mm diameter) were assigned into 24 groups (n=10) according to the combination of surface treatment (none, air abrasion with Al2O3 particles, or Er:YAG laser irradiation with 200mJ of energy intensity), metal primer (None, Alloy Primer, Metal Primer II or Metaltite), and resin cement (Panavia F2.0 or Calibra). Fragments of dentin were luted to ceramic surfaces, specimens were fixed in th abrasion with Al2O3 particles resulted in increased bond strength for both resin cements. Air abraded and laser irradiated specimens presented higher bond strength with Calibra resin cement than with Panavia F2.0. Both resin cements presented similar behavior on untreated surfaces. The three metal conditioners presented similar results regardless of the surface treatment and resin cement, significantly increasing the bond strength. It could be concluded that, although irradiation with 200mJ of energy intensity promotes superficial alterations on the Y-TZP ceramic, only the association of air abrasion with Al2O3 particles and metal primers application constitutes an effective technique for bonding resin cements to Y-TZP ceramicsDoutoradoDentísticaDoutor em Clínica Odontológic

Análise da influência do posicionamento do fotopolimerizador sobre a rugosidade superficial da resina composta – estudo in vitro

Introdução: uma adequada polimerização da resina composta proporciona um bom desempenho clínico e propriedades físicas satisfatórias na restauração. A conversão de monômeros em polímeros depende não só da luz visível emitida pelo fotopolimerizador e do sistema fotoiniciador presente na resina composta, como também da quantidade de energia que alcança a resina composta e que está na dependência de como essa luz é aplicada sobre a resina. Objetivo: verificar a influência do posicionamento da ponta de um fotopolimerizador de amplo espectro sobre a rugosidade de duas resinas compostas. Metodologia: previamente à confecção dos corpos de prova, foi realizada a randomização de quatro grupos experimentais (n=10) para locação dos corpos de prova, da resina Vittra APS (FGM) em duas apresentações (Vittra APS Esmalte-bleach e a Vittra APS Dentina A0) e duas variações do posicionamento da ponta do fotopolimerizador (0º e 20º). Foram confeccionados quarenta corpos de prova cilíndricos em resina composta, na dimensão 6 x 1,5 mm. Valores da Ra foram registrados usando-se um rugosímetro e analisados estatisticamente (Shapiro-Wilk/ANOVA). A rugosidade superficial (Ra) de topo de cada corpo de prova foi individualmente avaliada, sendo realizadas três leituras por superfície em posições diferentes. Resultados: não foi verificada significância estatística da interação entre os fatores, nem foram notadas diferenças estatisticamente significativas entre os fatores isolados. Dentre os posicionamentos analisados, constatou-se que o fotopolimerizador a 20º não alterou a rugosidade das resinas utilizadas. Conclusão: a variação da angulação da ponta do fotopolimerizador em 20o não alterou a rugosidade superficial das resinas testadas

Photodynamic therapy associated with full-mouth ultrasonic debridement in the treatment of severe chronic periodontitis: a randomized-controlled clinical trial

Background: Photodynamic therapy (PDT) is a method of microbial reduction which can benefit periodontal treatment in areas of difficult access, such as deep pockets and furcations. The aim of this randomized controlled clinical trial was to evaluate the effects of PDT as an adjunct to full-mouth ultrasonic debridement in the treatment of severe chronic periodontitis. Material and Methods: Twenty-two patients with at least one pocket with a probing depth (PD) of ≥7 mm and one pocket with a PD of ≥5 mm and bleeding on probing (BOP) on each side of the mouth were included, characterizing a split mouth design. The control group underwent full-mouth ultrasonic debridement and the test group received the same treatment associated with PDT. The PDT was performed on only one side of the mouth and the initial step consisted of subgingival irrigation with 0.005% methylene blue dye. Two minutes after applying the photosensitizer, the low power laser – AsGaAl (Photon Lase III – PL7336, DMC, São Carlos -São Paulo, Brazil) was applied (660 nm, 100 mW, 9 J, 90 seconds per site, 320 J/cm 2 , diameter tip 600 µm). The following clinical parameters were evaluated: plaque index, gingival index, BOP, gingival recession (GR), PD, and clinical attachment level (CAL). All parameters were collected before, 1, 3 and 6 months after treatment. Results: An improvement in BOP, PD and CAL was observed after treatment, in both groups, but without any difference between them. After 6 months, the PD decreased from 5.11±0.56 mm to 2.83±0.47 mm in the test group (

Photodynamic therapy associated with full-mouth ultrasonic debridement in the treatment of severe chronic periodontitis: a randomized-controlled clinical trial

BACKGROUND: Photodynamic therapy (PDT) is a method of microbial reduction which can benefit periodontal treatment in areas of difficult access, such as deep pockets and furcations. The aim of this randomized controlled clinical trial was to evaluate the effects of PDT as an adjunct to full-mouth ultrasonic debridement in the treatment of severe chronic periodontitis. MATERIAL AND METHODS: Twenty-two patients with at least one pocket with a probing depth (PD) of ≥7 mm and one pocket with a PD of ≥5 mm and bleeding on probing (BOP) on each side of the mouth were included, characterizing a split mouth design. The control group underwent full-mouth ultrasonic debridement and the test group received the same treatment associated with PDT. The PDT was performed on only one side of the mouth and the initial step consisted of subgingival irrigation with 0.005% methylene blue dye. Two minutes after applying the photosensitizer, the low power laser - AsGaAl (Photon Lase III - PL7336, DMC, São Carlos -São Paulo, Brazil) was applied (660 nm, 100 mW, 9 J, 90 seconds per site, 320 J/cm(2), diameter tip 600 µm).The following clinical parameters were evaluated: plaque index, gingival index, BOP, gingival recession (GR), PD, and clinical attachment level (CAL). All parameters were collected before, 1, 3 and 6 months after treatment. RESULTS: An improvement in BOP, PD and CAL was observed after treatment, in both groups, but without any difference between them. After 6 months, the PD decreased from 5.11±0.56 mm to 2.83±0.47 mm in the test group (p<0.05) and from 5.15±0.46 mm to 2.83±0.40 mm in the control group (p<0.05). The CAL changed, after 6 months, from 5.49±0.76 mm to 3.41±0.84 mm in the test group (p<0.05) and from 5.53±0.54 to 3.39±0.51 mm in the control group (p<0.05). CONCLUSION: Both approaches resulted in significant clinical improvements in the treatment of severe chronic periodontits, however, the PDT did not provide any additional benefit to those obtained with full-mouth ultrasonic debridement used alone

Rationale, study design, and analysis plan of the Alveolar Recruitment for ARDS Trial (ART): Study protocol for a randomized controlled trial

Background: Acute respiratory distress syndrome (ARDS) is associated with high in-hospital mortality. Alveolar recruitment followed by ventilation at optimal titrated PEEP may reduce ventilator-induced lung injury and improve oxygenation in patients with ARDS, but the effects on mortality and other clinical outcomes remain unknown. This article reports the rationale, study design, and analysis plan of the Alveolar Recruitment for ARDS Trial (ART). Methods/Design: ART is a pragmatic, multicenter, randomized (concealed), controlled trial, which aims to determine if maximum stepwise alveolar recruitment associated with PEEP titration is able to increase 28-day survival in patients with ARDS compared to conventional treatment (ARDSNet strategy). We will enroll adult patients with ARDS of less than 72 h duration. The intervention group will receive an alveolar recruitment maneuver, with stepwise increases of PEEP achieving 45 cmH(2)O and peak pressure of 60 cmH2O, followed by ventilation with optimal PEEP titrated according to the static compliance of the respiratory system. In the control group, mechanical ventilation will follow a conventional protocol (ARDSNet). In both groups, we will use controlled volume mode with low tidal volumes (4 to 6 mL/kg of predicted body weight) and targeting plateau pressure &lt;= 30 cmH2O. The primary outcome is 28-day survival, and the secondary outcomes are: length of ICU stay; length of hospital stay; pneumothorax requiring chest tube during first 7 days; barotrauma during first 7 days; mechanical ventilation-free days from days 1 to 28; ICU, in-hospital, and 6-month survival. ART is an event-guided trial planned to last until 520 events (deaths within 28 days) are observed. These events allow detection of a hazard ratio of 0.75, with 90% power and two-tailed type I error of 5%. All analysis will follow the intention-to-treat principle. Discussion: If the ART strategy with maximum recruitment and PEEP titration improves 28-day survival, this will represent a notable advance to the care of ARDS patients. Conversely, if the ART strategy is similar or inferior to the current evidence-based strategy (ARDSNet), this should also change current practice as many institutions routinely employ recruitment maneuvers and set PEEP levels according to some titration method.Hospital do Coracao (HCor) as part of the Program 'Hospitais de Excelencia a Servico do SUS (PROADI-SUS)'Brazilian Ministry of Healt

OS AGENTES DESSENSIBILIZANTES ASSOCIADOS AO CLAREAMENTO DENTAL AFETAM AS CARACTERÍSTICAS ÓPTICAS DO ESMALTE E A PERMEABILIDADE DA DENTINA? Um estudo in vitro

Objetivos: Avaliar a variação da cor do esmalte, luminosidade e permeabilidade dentinária após clareamento com peróxido de hidrogênio a 35% associado a quatro dessensibilizantes. Métodos: foram obtidos de incisivos bovinos 100 corpos de provas (50 para análise de cor, 50 para permeabilidade). Foram imersos em solução de chá preto por 6 dias para coloração e foram distribuídas aleatoriamente em 5 grupos (n = 10) cada, de acordo com o dessensibilizante utilizado antes do clareamento dental. A avaliação da cor foi feita por espectrofotometria UV, e as curvas espectrais foram analisadas por parâmetros CIEL * a * b *. Avaliações foram realizadas em 3 momentos: antes da coloração, após a coloração e ao final do clareamento. Valores de condutância da permeabilidade foram obtidos com um simulador de pressão intrapulpar. Dados foram tabulados e analisados ​​estatisticamente (ANOVA / Tukey; α = 5%). Resultados: Não foi detectada diferença significativa na variação total da cor entre grupos clareados por associação com dessensibilizantes e o grupo controle. Todos os grupos experimentais apresentaram aumento significativo em sua luminosidade após o clareamento, sem variação entre estes no mesmo momento experimental. Dessensibilizantes e flúor - utilizado na dessensibilização - foram capazes de reduzir a permeabilidade, porém, o flúor não apresentou diferença estatística comparado ao grupo controle. Conclusão: O uso de dessensibilizantes prévios a clareamento, exceto fluoreto de sódio, reduziu a permeabilidade dentinária, não afetando o mecanismo de ação do clareamento com peróxido de hidrogênio a 35% no esmalte dentário. Após clareamento, os grupos mantiveram valores de permeabilidade reduzidos

Physicochemical changes in enamel submitted to pH cycling and bleaching treatment

Made available in DSpace on 2019-09-12T16:57:00Z (GMT). No. of bitstreams: 0 Previous issue date: 2018Objective: The purpose of this study was to assess the hardness, mineral content, surface roughness, and micromorphology of sound and slightly demineralized enamels, before and after bleaching procedure using 10% carbamide peroxide. Methods: Sixty bovine dental blocks were randomly divided into the following two groups: 30 slabs were submitted to three cycles of pH and 30 slabs were noncycled. Hardness (n=10) was measured using the microhardness tester with Knoop indenter under a 50 g load for 5 seconds. The calcium/phosphate (Ca/P) ratio (n=10) was obtained using a micro-energy-dispersive X-ray fluorescence (mu-EDXRF) spectrometer. The measurement of roughness average (n=10) was performed using a surface roughness tester. Specimens were bleached 6 hours/day during 21 days, and then, physicochemical properties were re-evaluated. Two additional specimens were carried out to evaluate surface micromorphology using the scanning electron microscopy. Data were statistically analyzed by ANOVA and Tukey's test (alpha=0.05). Results: Sound and slightly demineralized enamels showed no difference in Ca/P ratio after dental bleaching according to the mu-EDXRF analysis, but the Ca/P ratio decreased after bleaching for slightly demineralized enamel. Bleaching treatment decreased the hardness and increased the surface roughness, causing micromorphology alterations. Conclusion: Therefore, bleaching procedure promoted change in bovine enamel surface and increased the demineralization of slightly demineralized enamel but not affected the mineral content of sound enamel.[Eskelsen, Evania; Catelan, Anderson; Suzy Liporoni, Priscila Christiane] Universidade de Taubaté (Unitau), Dept Dent, R Expedicionario Ernesto Pereira 110, BR-12020330 Taubate, SP, Brazil[Aparecida Pinto Hernades, Natalia Maria; Baggio Aguiar, Flavio Henrique] Univ Estadual Campinas, Piracicaba Dent Sch, Dept Restorat Dent, Piracicaba, SP, Brazil[Silva Soares, Luis Eduardo] Univ Vale Paraiba, Res & Dev Inst, Lab Biomed Vibrat Spect, Sao Jose Dos Campos, SP, Brazil[Cavalcanti, Andrea Nobrega] Sch Med & Publ Hlth Bahia, Dept Restorat Dent, Salvador, BA, Brazil[Cavalcanti, Andrea Nobrega] Univ Fed Bahia, Salvador, BA, Brazi

Effects of Bleaching Agents Combined with Regular and Whitening Toothpastes on Surface Roughness and Mineral Content of Enamel

Made available in DSpace on 2019-09-12T16:53:49Z (GMT). No. of bitstreams: 0 Previous issue date: 2015Objective: The purpose of this study was to evaluate surface roughness and changes in the composition of enamel submitted to different bleaching protocols and toothbrushing with regular and whitening toothpastes. Background data: Bleaching treatment could promote morphological and chemical changes in enamel surface. Methods: Enamel blocks were randomized into nine groups (n=10) according to the bleaching treatment (no bleaching, control group; 6% hydrogen peroxide, HP; or 10% carbamide peroxide, CP) and toothpaste used (placebo, PL; regular, R; or whitening dentifrice, W). Bleaching was performed according to manufacturers' instructions and all groups were submitted to 30,000 cycles of simulated toothbrushing with toothpaste (PL, R, or W). Mineral content evaluation and enamel roughness were evaluated initially (T-1), after bleaching (T-2), and after toothbrushing (T-3), using an energy-dispersive micro X-ray fluorescence spectrometer and profilometry, respectively. Data were statistically analyzed with two way ANOVA, Tukey, and Dunnett tests (5%). Results: Enamel surface roughness was influenced by bleaching and toothbrushing. Surface roughness increased for the groups that brushed with the placebo dentifrice (CP+PL, HP+PL, C+PL) and for the control group that brushed with whitening dentifrice (C+W). Enamel Ca/P ratio decreased after bleaching, but toothbrushing, regardless of the dentifrice used, did not reduce the enamel mineral content. Conclusions: The bleaching treatment resulted in a decrease of enamel mineral content, but the studied dentifrices did not contribute to surface mineral loss.[Attia, Mariana Lerner; Cavalli, Vanessa; Freitas D'Arce, Maria Beatriz; do Rego, Marcos Augusto; Suzy Liporoni, Priscila Christiane] Universidade de Taubaté (Unitau), Dept Restorat Dent, BR-12020330 Taubate, SP, Brazil[do Espirito Santo, Ana Maria] Univ Fed Sao Paulo, Dept Math & Earth Sci, Diadema, SP, Brazil[Martin, Airton Abrahao] Univ Paraiba Valley, Res & Dev Inst IP&D, Sao Jose Dos Campos, SP, Brazil[Baggio Aguiar, Flavio Henrique; Lovadino, Jose Roberto; Suzy Liporoni, Priscila Christiane] Univ Estadual Campinas, Piracicaba Dent Sch, Dept Restorat Dent, Piracicaba, SP, Brazil[Cavalcanti, Andrea Nobrega] Univ Fed Bahia, Sch Med & Publ Hlth Bahia, Sch Dent, Area Restorat Dent, Salvador, BA, Brazil[Cavalcanti, Andrea Nobrega] Univ Fed Bahia, Sch Dent, Salvador, BA, Brazi