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| June 2008 | Courtesy of BEGO USA Spruing - Does size matter?
Have you ever considered why the manufacturers of pre-manufactured sprues offer you 8, 10, &, 12 gauge direct sprues and 4 & 6 gauge indirect sprues? When most technicians are asked this question their answer is “I use the sprue that is closest to the size of the restoration I’m casting.” Although this answer seems logical, the correct answer to the question relates to the density and flow ability of the alloy you are casting. Normally a Type III or IV gold has a density of 14 to 18g/cm3. These heavier density alloys have a high flow ability; they should be cast with a smaller diameter/higher gauge sprue which will maintain the speed and pressure of the alloy.On the contrary, lighter density alloys like Non-precious or high Palladium alloys with a density of 8.2 to 11g/cm3, should be waxed up with larger diameter sprues. This makes it easier for these poorer flowing, sluggish alloys to cast quickly. Keep in mind, when casting a large restoration, the reservoir should be equal in size no matter what diameter sprue is used. |
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 For more information, call your local dealer or BEGO USA, 1.800.342.2346 | |
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