JonB
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Last week Doug gave me a tip on investing UCLA abutments. I had my doubts, but thought - what the heck, anything would beat the last effort i had made on one. ***edit*** I had a single molar UCLA type crown in the lab and three large implant bar cases using UCLAs. I did the molar first and screwed it up with a poor investing technique. I hadn't done a UCLA in over 10 years. So I ordered a new UCLA and asked for advice and Doug came through. It was enough though to make me reconsider the wisdom of trying to cast 12 UCLAs spread over three arches and ruining any one of them. So I reasoned that a milled bar was a better idea. I learned two lessons - no three - in this one mistake. 1) to invest like Doug said, 2) to do milled bars instead for the precision, and 3) the value of this forum ***
His tip ( I hope Doug doesn't mind me saying) To thread a piece of floss or fishing line through the access hole before you invest and then just fill the ring as normal. As the investment comes up around the hole, it builds surface tension, but the string breaks the tension and the hole fills completely. Then you pull the string out and it pulls out any tiny little bubble with it.
You finish filling the ring and let it set, cast it, clean it up and you have a perfect, unmolested abutment.
Also you need to score a line around the area at the base of the crown/abutment where the alloy contours meet the titanium. This gives the alloy a break in its momentum during casting so it doesn't break through and spill onto the mating surfaces.
Great tip, Doug - it's a brilliant solution.
I only have one question... when i add this to my SOP - is using the floss this way inconsistent with its packaging?
His tip ( I hope Doug doesn't mind me saying) To thread a piece of floss or fishing line through the access hole before you invest and then just fill the ring as normal. As the investment comes up around the hole, it builds surface tension, but the string breaks the tension and the hole fills completely. Then you pull the string out and it pulls out any tiny little bubble with it.
You finish filling the ring and let it set, cast it, clean it up and you have a perfect, unmolested abutment.
Also you need to score a line around the area at the base of the crown/abutment where the alloy contours meet the titanium. This gives the alloy a break in its momentum during casting so it doesn't break through and spill onto the mating surfaces.
Great tip, Doug - it's a brilliant solution.
I only have one question... when i add this to my SOP - is using the floss this way inconsistent with its packaging?
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