Ceramic characterization and factography of resin-ceramic adhesive interface after different ceramic surface treatments

Orientador: Alvaro Della Bona, Altair A. Del Bel CuryTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: Este estudo avaliou o efeito do tratamento de superfície na resistência adesiva à tração (s) entre resina e as cerâmicas IPS Empress®(E1) e VITAVM7®(V7) e o modo de falha nessa interface adesiva. A metodologia proposta teve por finalidade testar a hipótese de que a s entre resina e cerâmica é controlada pelo tratamento de superfície das cerâmicas. Foram confeccionados 10 blocos de uma cerâmica a base de leucita, (E1) e de uma cerâmica feldspática com duas fases vítreas (V7), que foram polidos até a granulação de 1 µm. Os blocos de cada cerâmica foram divididos aleatoriamente em dois grupos e tiveram suas superfícies tratadas como segue (n=5): Grupos E1HF e V7HF: aplicação de ácido hidrofluorídrico a 9,5% (HF - Ultradent) aplicado por 60 s; Grupos E1CS e V7CS: jateamento com partículas de alumina modificadas por sílica (CS ¿ Cojet System, 3M-Espe), aplicado por 15 s. As superfícies cerâmicas tratadas foram lavadas, secadas e o silano foi aplicado deixando-o evaporar. Aplicaram-se duas camadas finas de adesivo (Single Bond, 3M), seguido da aplicação de camadas de 2 mm de resina composta (Z250, 3M), que foram fotopolimerizadas durante 40 s cada uma. Os blocos cerâmica-adesivo-resina composta foram seccionados em dois eixos, x e y, obtendo-se corpos-de-prova em forma de barras (n=30), com área adesiva média de 1,04 mm2. Os corpos-de-prova foram armazenados em água destilada a 37°C por uma semana antes do teste de tração em uma máquina de ensaios universal com velocidade de carga de 1.0 mm.min-1, seguido da análise microscópica da superfície fraturada. A análise estatística foi realizada pela análise de variância, teste de Tukey (a=.01) e análise de Weibull. As médias e desvio padrão da s (MPa) foram: E1HF: 29,8±4,5(a); E1CS: 24,6±5,6(b); V7HF: 22,3±4,0(b); V7CS: 15,7±6,9(c). Os valores médios de s do Grupo E1HF foram significativamente maiores que os valores médios dos demais grupos (p=0,0001). As duas cerâmicas apresentaram valores médios de s significativamente maiores quando tratadas com HF do que com CS (p=0,0001). Todas as fraturas ocorreram dentro da zona adesiva. O módulo de Weibull (m) foi mais alto para o Grupo E1HF (7,66), e o Grupo V7CS mostrou o valor mais baixo de m (2,54). Os resultados confirmam a hipótese inicial de que a s da resina à cerâmica é controlada, primariamente, pelo tratamento de superfície do material cerâmicoAbstract: This study evaluated the effect of ceramic surface treatments on tensile bond strength (s) and the mode of failure of a resin bonded to two types of ceramics, testing the hypothesis that s of ceramics to resin is controlled by the ceramic surface treatment. Methods: Ten blocks of each the hot-pressed leucite-based ceramic (E1- IPS Empress) and the two-phase glassy feldspathic ceramic (V7-VITAVM7) were fabricated, polished through 1 µm alumina abrasive, and divided into two groups per ceramic (n=5): Groups E1HF and V7HF, 9.5% hydrofluoric acid (HF) was applied for 60 s; Groups E1CS e V7CS, silica coating (CS) using Cojet System (3M-Espe) for 15 s. The treated ceramic surfaces were washed and dried. Silane was applied and let to evaporate. An adhesive resin (Single Bond, 3M) followed by a resin composite (Z250, 3M) were applied on the ceramic treated surfaces and light cured. The composite-ceramic blocks were cut to produce bar-shaped specimens with a mean bonding area of 1.04 mm2 (n=30). Specimens were stored in 37°C distilled water for 1 week before tensile loading to failure in a universal testing machine with cross-head speed of 1.0 mm.min-1. Fracture surfaces were examined under scanning electron microscope (SEM). Results were statistically analyzed using one way ANOVA, Tukey¿s test and Weibull analyses. Results: Mean s and standard deviation (MPa) values were as follows: E1HF: 29.8±4.5(a); E1CS: 24.6±5.6(b); V7HF: 22.3±4.0(b); V7CS: 15.7±6.9(c). Mean s value of Group E1HF was statistically higher than the other Groups mean values (p=0.0001). HF treatment produced significantly higher mean s value than CS treatment, independent of the ceramic material (p=0.0001). All fractures occurred within the adhesion zone. E1HF showed the highest Weibull modulus (m) value (7.66) and V7CS exhibited the lowest m value (2.54). Conclusion: Results confirmed the testing hypothesis that s of ceramics to resin is controlled primarily by the ceramic surface treatmentDoutoradoProtese DentalDoutor em Clínica Odontológic

Effect of cariogenic challenge on the stability of dentin bonds

Objective: The oral environment is subject to biofilm accumulation and cariogenic challenge, and few studies exist on the effect of these factors on the bond strength of adhesive systems. The aim of this study was to test if the exposure of adhesive interfaces to cariogenic challenge under biofilm accumulation could promote higher degradation than the exposure to biofilm accumulation alone. Material And Methods: Five molars were ground until exposure of medium dentin and then restored (Single Bond 2 and Z250 3M ESPE). The tooth/resin sets were cut to obtain beam-shaped specimens, which were distributed according to the aging conditions (n=20): water for 24 h (control); biofilm under cariogenic challenge for 3, 5 or 10 days; biofilm without cariogenic challenge for 10 days; and water for 3 months. Microcosm biofilms were formed from human saliva and grown in a saliva analogue medium, supplemented or not with sucrose to promote cariogenic challenge. Specimens were tested for microtensile bond strength, and failure modes were classified using light microscopy. Bond strength data were analyzed using ANOVA and failure modes were analyzed using ANOVA on ranks (α=0.05). Results: No significant differences in bond strength were detected among the aging methods (P=0.248). The aging period was associated with an increase in the frequency of adhesive failures for the groups aged for 10 days or longer (

Movimentação dental linear em protese total superior em função dos materiais de inclusão e metodos de polimerização

Orientadores : Saide Sarckis Domitti, Simonides ConsaniDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaMestrad

Effect of standardized training in combination with masseter sensitization on corticomotor excitability in bruxer and control individuals : a proof of concept study

Recently, it has been proposed that bruxism could represent an overlearned behavior due to the absence of corticomotor plasticity following a relevant tooth-clenching task (TCT). This study assessed the modulatory effects of a nerve growth factor (NGF) injection on masseter muscle corticomotor excitability, jaw motor performance, pain, and limitation in bruxer and control participants following a TCT. Participants characterized as definitive bruxers or controls were randomly assigned to have injected into the right masseter muscle either NGF or isotonic saline (IS), resulting in a study with 4 arms: IS_Control (n = 7), IS_Bruxer (n = 7); NGF_Control (n = 6), and NGF_Bruxer (n = 8). The primary outcome was the masseter motor evoked potential (MEP) amplitude measured at baseline and after a TCT. After the interventions, significantly higher and lower MEP amplitude and corticomotor map area were observed, respectively, in the IS_Control and NGF_Control groups (P < 0.05). Precision and accuracy depended on the series and target force level with significant between-group differences (P < 0.01). NGF-induced masseter muscle sensitization, in combination with a training-induced effect, can significantly impact the corticomotor excitability of the masseter muscle in control participants indicating substantial changes in corticomotor excitability, which are not observed in bruxers. These preliminary findings may have therapeuthic implications for the potential to "detrain" and manage bruxism, but further studies with larger sample sizes will be needed to test this new concept

Masking ability of different ceramic systems over a darkened substrate: case report

This clinical report describes the masking ability of IPS e.max ceramic (lithium disilicate glass-ceramic and polycrystalline zirconia) used over darkened (metallic post) and natural-colored backgrounds. Initially, medium-opacity lithium disilicate glass-ceramic framework (IPS e.max Press MO) was used over both backgrounds. It was observed that at the minimum thickness recommended by the manufacturer, the medium-opacity lithium disilicate glass-ceramic framework did not provide sufficient masking ability over the darkened background (metallic post). Then, because of its inadequate masking ability, the lithium disilicate glass-ceramic framework over the metallic post was replaced with polycrystalline zirconia (IPS e.max ZirCAD). It was concluded that using polycrystalline zirconia resulted in better masking ability and superior final aesthetic appearance over a darkened background

Effect of cariogenic challenge on the stability of dentin bonds

Objective: The oral environment is subject to biofilm accumulation and cariogenic challenge, and few studies exist on the effect of these factors on the bond strength of adhesive systems. The aim of this study was to test if the exposure of adhesive interfaces to cariogenic challenge under biofilm accumulation could promote higher degradation than the exposure to biofilm accumulation alone. Material And Methods: Five molars were ground until exposure of medium dentin and then restored (Single Bond 2 and Z250 3M ESPE). The tooth/resin sets were cut to obtain beam-shaped specimens, which were distributed according to the aging conditions (n=20): water for 24 h (control); biofilm under cariogenic challenge for 3, 5 or 10 days; biofilm without cariogenic challenge for 10 days; and water for 3 months. Microcosm biofilms were formed from human saliva and grown in a saliva analogue medium, supplemented or not with sucrose to promote cariogenic challenge. Specimens were tested for microtensile bond strength, and failure modes were classified using light microscopy. Bond strength data were analyzed using ANOVA and failure modes were analyzed using ANOVA on ranks (α=0.05). Results: No significant differences in bond strength were detected among the aging methods (P=0.248). The aging period was associated with an increase in the frequency of adhesive failures for the groups aged for 10 days or longer (P<0.001). Conclusion: Aging leads to a higher prevalence of interfacial adhesive failures, although this effect is not associated with cariogenic challenge or reduction in bond strengths

Effect of cariogenic challenge on the stability of dentin bonds

Objective: The oral environment is subject to biofilm accumulation and cariogenic challenge, and few studies exist on the effect of these factors on the bond strength of adhesive systems. The aim of this study was to test if the exposure of adhesive interfaces to cariogenic challenge under biofilm accumulation could promote higher degradation than the exposure to biofilm accumulation alone. Material And Methods: Five molars were ground until exposure of medium dentin and then restored (Single Bond 2 and Z250 3M ESPE). The tooth/resin sets were cut to obtain beam-shaped specimens, which were distributed according to the aging conditions (n=20): water for 24 h (control); biofilm under cariogenic challenge for 3, 5 or 10 days; biofilm without cariogenic challenge for 10 days; and water for 3 months. Microcosm biofilms were formed from human saliva and grown in a saliva analogue medium, supplemented or not with sucrose to promote cariogenic challenge. Specimens were tested for microtensile bond strength, and failure modes were classified using light microscopy. Bond strength data were analyzed using ANOVA and failure modes were analyzed using ANOVA on ranks (&#945;=0.05). Results: No significant differences in bond strength were detected among the aging methods (P=0.248). The aging period was associated with an increase in the frequency of adhesive failures for the groups aged for 10 days or longer (P<0.001). Conclusion: Aging leads to a higher prevalence of interfacial adhesive failures, although this effect is not associated with cariogenic challenge or reduction in bond strengths