Resumo O presente estudo é um estudo clínico prospectivo, controlado, randomizado e de longo curto prazo, com o objetivo de avaliar o desempenho clínico de restauraç ões adesivas cerâmica vítrea reforçada com dissilicato de lítio e cerâmica feldspática por um período de até 2 anos. Um total de 11 pacientes (7 mulheres, 4 homens; faixa etária: 18-60 anos, idade média: 39 anos) foram inseridas para este estudo. Cada paciente recebeu duas restaurações por grupo em um delineamento de boca dividida. LD: Onze onlays, realizados com cerâmica à base de dissilicato de lítio (IPS e.max CAD, Ivoclar Vivadent, Schaan, Liechtenstein); e FP: Onze onlays, realizados com cerâmica feldspática (Vita Mark II, Vita Zanhfabrik, Bad Säckingen). Os retornos foram realizados em 2 semanas (linha de base = R1), 1 ano (R2) e 2 anos (R3) após a cimentação, por três investigadores independentes, cegos e calibrados, usando espelhos, óculos de aumento, sondas e radiografias interproximais. Foram avaliadas a sensibilidade pós-operatória, cárie secundária, integridade marginal, descoloração marginal, correspondência de cores, rugosidade da superfície, integridade dentária e integridade da restauração. O teste de Friedman (95%) foi utilizado para determinar se havia uma diferença estatisticamente significante na comparação periódica dos parâmetros nas restaurações cerâmicas. Um total de 95,4% das restaurações estava clinicamente aceitável no retorno de 2 anos, sem diferença para qualquer parâmetro de avaliação para ambos os materiais cerâmicos. Com base nos dados de 2 anos, as restaurações CAD-CAM fabricados com cerâmica feldspática e à base de dissilicato de lítio apresentaram desempenho clínico semelhante.

Abstract The present study was a prospective, controlled, randomized, clinical short-term trial aiming to evaluate the clinical performance of adhesively luted, lithium disilicate and feldspathic glass-ceramics onlays over a period up to 2 years. A total of 11 patients (7 female, 4 male; age range: 18-60 years, mean age: 39 years) were selected for this study. Each patient received a maximum of two restorations per group in a split-mouth-design. LD: Eleven onlays, performed with lithium disilicate-based ceramic (IPS e.max CAD, Ivoclar Vivadent, Schaan, Liechtenstein), and FP: Eleven onlays, performed with feldspathic ceramic (Vita Mark II, Vita Zanhfabrik, Bad Säckingen). Recalls were performed at 2 weeks (baseline = R1), 1 year (R2) and 2 years (R3) after the cementation by three calibrated blinded independent investigators using mirrors, magnifying eyeglasses, probes and bitewing radiographs. The postoperative sensitivity, secondary caries, marginal integrity, marginal discoloration, color match, surface roughness, tooth integrity, and restoration integrity were evaluated. The Friedman test was used to determine if there was a statistically significant difference in time-to-time comparison of the parameters in the ceramics restorations. A total of 95.4% of the restorations were clinically acceptable at the 2-year recall, without a difference for any evaluation parameter for both ceramic materials. Based on the 2-year data, the CAD-CAM onlays manufactured with feldspathic and lithium-disilicate based ceramics showed similar clinical performance.

Abstract The present study investigated the effect of grinding on roughness, flexural strength, and reliability of a zirconia ceramic before and after heat treatment. Seven groups were tested (n = 15): a control group (labeled CG, untreated), and six groups of samples ground with diamond discs, simulating diamond burs, with grits of 200 µm (G80); 160 µm (G120), and 25 µm (G600), either untreated or heat-treated at 1200°C for 2 h (labeled A). Yttria tetragonal zirconia polycrystal discs were manufactured, ground, and submitted to roughness and crystalline phase analyses before the biaxial flexural strength test. There was no correlation between roughness (Ra and Rz) and flexural strength. The reliability of the materials was not affected by grinding or heat treatment, but the characteristic strength was higher after abrasion with diamond discs, irrespective of grit size. The X-ray diffraction data showed that grinding leads to a higher monoclinic (m) phase content, whereas heat treatment produces reverse transformation, leading to a fraction of m-phase in ground samples similar to that observed in the control group. However, after heat treatment, only the G80A samples presented strength similar to that of the control group, while the other groups showed higher strength values. When zirconia pieces must be adjusted for clinical use, a smoother surface can be obtained by employing finer-grit diamond burs. Moreover, when the amount of monoclinic phase is related to the degradation of zirconia, the laboratory heat treatment of ground pieces is indicated for the reverse transformation of zirconia crystals.