The Influence Of Two Different Casting Temperatures On The Incorporated Keeper

The incorporated keeper is the mostly applicated style of magnetic attachment in clinic. In alien it is noble metal that was casted with keeper for the tooth cap, but the price of it is so high that many people in our country couldn't pay for it. So a new cheaper but similar capacity cast technique should be achieved. In this study high temperature cast with normal high-fused alloy was compared with the medium one of: the morphological view and thickness of keeper oxide film, the combined quality between the keeper and the cast alloy, the magnetic force and corrosion-resistant. And the following conclusions was drawn :1 .The oxide film quality of medium temperature group (Group 2) was better than that of high temperature group (Group 1): the smaller oxide grain, no fissure among film, firmly combining with basal metal, etc. On the cast surface of alloy and keeper surface a crooked and pressed oxide film was observed, especially in Group 1.2.The oxide film thickness of Group 2 was less than Group 1 : Group 1 , investment surface: 7.59 u m , alloy surface: 6.17 u m ; Group 2 , investment surface: 4.65 U m , alloy surface: 3.95 n m. The number difference between the two groups was only 3 U m, and the largest thickness was not beyond 10 u m. So the thickness of oxide film would have little influence in clinic.3.The metalographic view of two groups casted keeper was both similar with the uncasted keeper: the shape was regular; the crystalline grade wasGrade 3 ; the mean diameter of crystalline grain was 140um; and the crystalline border was not changed.4.Both of two groups had satisfied combined capacity between the keeper and alloy. Among the keeper cap the oxide and metal of keeper and cast alloy was fused and interlaced near the casting surface area, which was believed beneficial to the cast quality. Group 1 was more obvious than Group 2 .5.The magnetic force of two groups had no stastistic difference (Group 1: 433.8 g , Group 2: 433.6g ), but was lower than the uncasted keeper ( 451.8g ). The measured figure of the magnetic force was satisfied to the clinical application.