Avaliação do desajuste marginal de coroas totais fundidas em titanio comercialmente puro utilizando diferentes padrões para fundição / Evaluation of marginal misfit of casting commercially pure titanium total crow using differrent pattern for casting

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

Patterns for casting metallic restorations are usually obtained from wax. However, it is speculated that increased marginal misfits could be created caused by dimensional changes during the removal of the pattern from the cast. Therefore, chemically activated acrylic resin is a routinely option in dental commercial laboratories. The characteristics of titanium include biocompatibility, low thermal conductivity, low cost and high mechanical resistance becoming the material of choice for implants and the focus of innumerous studies in prosthetic field such as crowns. To obtain the lowest marginal misfit in crowns, it is recommended that titanium appliances should be cast using wax as pattern, with no evaluation on the use of acrylic resin for this purpose. The aim of this study was to compare the marginal adjustment of crowns cast in commercially pure titanium (CP Ti - Tritan; Dentaurum, Germany)using wax (control), and the acrylic resins Duralay (Reliance Dental, Mfg Co., USA) and Pattern Resin (GC America Inc., USA) as patterns. Ten bovine teeth were prepared for full crown restorations. Impressions were made in silicone material and replicated in type IV dental stone. Ten 0.7 mm-casting patterns were made for each groups. The crowns were cast in CP Ti in a plasma-vacuum casting machine. After casting, the crowns were removed from the investment and adjusted on the respective preparation. For the marginal misfit readings, a 0.5µm-traveling microscope was used. Three readings were taken from each crown-preparation interface. The means were calculated and submitted to analysis of variance and Tukey test at 5% probability lever. Misfits of 151µm were obtained for the crowns cast using wax as patterns; 153µm when Duralay was used; and, 165µm for the crowns made from Pattern Resin. No significant differences were seen among the groups, and the values about 150µm

ASSUNTO(S)

crow (dentistry) coroas (odontologia) casting fundição titanio titanium

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