RESUMO
<p><b>OBJECTIVE</b>To compare the influence of different investment materials, methods and crown height on the cast shrinkage of full crowns made of dental base metal alloy.</p><p><b>METHODS</b>All of the 288 wax patterns were made and divided into three groups according to their crown height. In every group, wax patterns were invested in metal rings and paper rings with three types investment material and cast with base metal alloys. Then the inside diameters of castings were measured and analyzed by statistical package SPSS.</p><p><b>RESULTS</b>Differences between groups invested with the three types of material were significant(P < 0.01). There were significant difference between the groups investing with metal rings and paper rings(P < 0.01).</p><p><b>CONCLUSION</b>The component of investment material and invested ring can affect the cast shrinkage of dental base metal alloy apparently.</p>
Assuntos
Humanos , Coroas , Padrões de Referência , Ligas Dentárias , Padrões de Referência , Revestimento para Fundição Odontológica , Técnica de Fundição Odontológica , Moldagem de Cera para Incrustações , Química , Classificação , Teste de Materiais , Métodos , Ligas Metalo-Cerâmicas , Padrões de Referência , Ajuste de PróteseRESUMO
<p><b>OBJECTIVE</b>The purpose of this study was to compare the compressive strength of phosphate-bonded investments.</p><p><b>METHODS</b>The three sorts of investments were mixed according to manufacturer's recommendation before poured in the molds. After heated up to 900 degrees C, every sample was mounted on a universal experimental machine to test its compressive strength in ambient.</p><p><b>RESULTS</b>Significant differences were found between the four groups(P < 0.01).</p><p><b>CONCLUSION</b>From the data above it is concluded that the compressive strength of X-20 Chrome Investment mixed with the special liquid was the highest.</p>