Influência do ciclo de sinterização da porcelana na adaptação marginal de infraestruturas de NiCrTi em função da biomecânica do preparo

• Autor(a) principal: Almeida, Juliana Gomes Dos Santos Paes
• Data de Publicação: 2010
• Outros Autores: Guedes, Carlos Gramani, Rached, Filipe de Oliveira Abi [UNESP], Fonseca, Renata Garcia [UNESP]
• Tipo de documento: Artigo
• Idioma: por
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://www.revodontolunesp.com.br/article/51ae4aa51ef1faca3d00349f; http://hdl.handle.net/11449/125751
• topic: Marginal adaptation; Metal ceramic alloys; Tooth preparation; Adaptação marginal; Ligas metalocerâmicas; Preparo dental

A metal coping may undergo changes during porcelain firing, which compromises its marginal adaptation. The use of NiCrTi alloy proposes to minimize this effect through the high melting point of titanium present in its composition. This study evaluated the influence of porcelain firing cycle on the marginal adaptation of NiCrTi copings in different preparation designs. Forty standardized metal dies were fabricated with the following combinations finish line/convergence of the axial walls: 1) shoulder/6°; 2) shoulder/20°; 3) sloping shoulder/6°; 4) sloping shoulder/20°. On each die a metal ceramic restoration coping was made. The die/coping set was stabilized with orthodontic elastics, divided into four equidistant areas with three measurement points each and a cementation pressure was simulated. The measurements were taken under a stereomicroscope (32×). After the first measurement, the copings were submitted to sintering cycles simulating porcelain application. For repeated measurements, the same procedures described above were performed. Data were submitted to Student’s-t test, 1-way ANOVA and Tukey´s test (α = 0.05). Adaptation means (µm) before and after porcelain firing in different preparations were: 1) 111.92 and 127.31; 2) 124.15 and 135.48; 3) 122.19 and 138.77; 4) 166.09 and 186.72; respectively. The porcelain firing impaired adaptation, regardless of the preparation design. The preparation in a 20° sloping shoulder provided a worse adaptation when compared with preparations that had 6° and 20° shoulder, which were statistically equal. The 6° sloping shoulder was statistically equal to the other three preparation designs.