Search

SUMMARY Purpose: Feldspathic ceramic restorations can be obtained by different techniques (stratification or computer-aided design/computer-aided manufacturing [CAD/CAM] blocks) and finishing procedures (polishing or glaze application). This study evaluated the effects of techniques and finishing procedures on surface properties, biofilm formation, and viability of human gingival fibroblasts (FMM-1) in contact with these materials. Methods and Materials: Ceramic specimens were obtained through a stratification technique (Vita VM9) and from CAD/CAM blocks (Vita Blocs Mark II; both Vita Zahnfabrik) and their surfaces were finished by polishing (ceramisté diamond rubbers + polishing paste; “p” subgroups) or glaze spray application + sintering (“g” subgroups). Roughness (Ra and RSm parameters) and surface free energy (SFE) were measured. Early biofilm formation of Streptococcus mutans, Streptococcus sanguinis, and Candida albicans was evaluated by counting colony-forming units (CFU). MTT (3-[4.5-dimethyl-thiazol-2-yl-]-2.5-diphenyl tetrazolium bromide) cytotoxicity test evaluated cellular viability for the growth of FMM-1 after 24 hours and seven days of contact. Scanning electron microscopy (SEM) and three-dimensional optical profilometry were performed to qualitatively analyze the surface. Data were analyzed by analysis of variance, Tukey test, and t-test (all α=0.05). Results: Polished samples presented lower roughness (Ra, p=0.015; RSm, p=0.049) and higher SFE (p=0.00). Streptococci had higher CFU in all groups, but the CFU of C albicans was lower for polished samples. Biofilm formation was influenced by the interaction of all factors (p=0.018), and the materials showed no cytotoxicity to FMM-1 growth. Conclusions: Polishing resulted in the lowest values for surface roughness and higher SFE values. Polished ceramics showed less C albicans adherence while the adherence of Streptococci was greater than C albicans in all conditions.

Made available in DSpace on 2019-10-06T16:47:35Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-12-01 It is important to predict the wear behavior of a material as well as its potential to wear antagonized restorative materials. Thus, this study investigated the performance of zirconia-reinforced lithium silicate (ZLS) after wear with different antagonists. Thirty discs of ZLS were made and divided into three groups according to the antagonist (n = 10). Ten cylinders of each antagonist were also made. The parameters for the simulation of wear were: 30N, horizontal movement of 6 mm, and 1.7 Hz, totaling 300,000 cycles, in distilled water. Wear measurements (volume losses (mm3)) on the ZLS and antagonists were performed by digital optical profilometry or an analytical balance. Hardness of all materials was also measured, whereas roughness and Scanning Electron Microscopy (SEM) were only accessed for the ZLS. The wear and hardness values were subjected to one-way ANOVA and the Tukey Test (95%), while the roughness data was analyzed with paired T-test (95%). The hardness means of all materials were statistically different (zirconia > steatite = ZLS > acrylic resin) (p = 0.0001). Zirconia and steatite severely worn ZLS and only acrylic resin worn surfaces could be measured for roughness, which was significantly higher after wear (p = 0.007). SEM showed the ZLS's wear tracks when worn by steatite and zirconia. It was possible to observe differences of ZLS wear patterns depending on the antagonist and quantify the volumes worn with steatite (17.61 ± 2.65) and zirconia (41.98 ± 19.45), which were significantly different (p = 0.001). Acrylic resin promoted a superficial wear on ZLS that could not be quantified. In terms of the antagonists' materials, zirconia presented significantly different less volume loss compared to acrylic resin and steatite (p = 0.000). It can be concluded that zirconia caused more wear on ZLS than steatite and acrylic resin. São Paulo State University (Unesp) Institute of Science and Technology at São José dos Campos Department of Dental Materials and Prosthodontics Technological Institute of Aeronautics Physics department, Praça Marechal Eduardo Gomes 50 Federal University of Santa Maria (UFSM) Restorative Dentistry Department, Marechal Floriano 1184 São Paulo State University (Unesp) Institute of Science and Technology at São José dos Campos Department of Dental Materials and Prosthodontics

This study evaluated the influence of zirconia surface finishes on the wear of an enamel analogue. 40 zirconia discs were divided into four groups: control (without finish); glazed; polished; polished and glazed. All samples were subjected to wear against steatite antagonists. The specimens underwent roughness, topographic, scanning electron microscopy (SEM) and wettability analyses. Quantitative wear measurements were performed on both steatites and discs. To measure wear of steatites the weight before and after the test and the diameter after the test were used. Profilometer measurements were performed to determine the wear on discs. Roughness, volumetric wear and mass loss were analyzed using the Kruskal-Wallis and Dunn tests (5%), while contact angle values were analyzed with One-way ANOVA and Tukey tests (5%). The polished group had the lowest roughness means, being statistically different from the other groups (p-value=0.0001). The glazed group presented the lowest steatite volumetric wear (p-value=0.0001), but not statistically different from the polished and glazed group, whereas these groups presented the highest zirconia volumetric wear, with statistically different (p-value=0.0002) compared to the others. SEM showed irregularities on the control groups surface, grooves on the polished group, and a homogeneous surface for the glazed group with a few pores. All groups presented contact angles lower than 90 degrees, characterizing hydrophilic surfaces. It can be concluded that just glazed zirconia caused less wear on the antagonist when compared to no finish and polished zirconia. Resumo Este estudo avaliou a influência dos acabamentos superficiais da zircônia no desgaste de um análogo de esmalte. 40 discos de zircônia foram divididos em quatro grupos: controle (sem acabamento); glazeado; polido; polido e glazeado. Todas as amostras foram submetidas ao desgaste contra antagonistas de esteatita. Os espécimes foram submetidos à análise de rugosidade, topografia, microscopia eletrônica de varredura (MEV) e análise de molhabilidade. Medidas quantitativas de desgaste foram realizadas nos antagonistas e nos discos de zircônia. Para medir o desgaste das esteatitas, foi mensurado o peso antes e depois do desgaste e o diâmetro após o teste. A análise de perfilometria mensurou o desgaste dos discos. Rugosidade, desgaste volumétrico e perda de massa foram analisados pelos testes de Kruskal-Wallis e Dunn (5%), enquanto os valores de ângulo de contato foram analisados com os testes One-way ANOVA e Tukey (5%). O grupo polido apresentou as menores médias de rugosidade, sendo estatisticamente diferente dos demais grupos (p-valor=0,0001). O grupo glazeado apresentou o menor desgaste volumétrico do antagonista (p-valor=0,0001), mas não foi estatisticamente diferente do grupo polido e glazeado, enquanto que esses grupos apresentaram o maior desgaste volumétrico da zircônia, com diferença estatisticamente diferente (p-valor=0,0002) em comparação com os outros. MEV mostrou irregularidades na superfície do grupo controle, sulcos no grupo polido e uma superfície homogênea para o grupo glazeado, com poucos poros. Todos os grupos apresentaram ângulos de contato menores que 90 graus, caracterizando superfícies hidrofílicas. Dentro das limitações deste estudo in vitro, é possível concluir que zircônia glazeada causou menos desgaste ao antagonista quando comparada a zircônia sem tratamento ou polida. Além disso, não foi encontrada diferença no desgaste do antagonista para os grupos de zirconia polida e controle.