My partner Scott had a patient in this afternoon to try to save an implant retained bar that supported a denture. The original bar did not fit passively and allow all the fixtures to be engaged. Two of the fixtures had lost bone around the top few threads and were suffering from peri-implantitis. There were several challenging pieces of the appointment, not the least of which was sectioning the bar after it was removed so it could be reassembled with Duralay pattern resin allowing the lab to solder it back together for a passive fit. I have had the pleasure of sectioning a bar before and I struggle with several things. First they are difficult to hold. Second it is tedious to cut through the metal, and you have to choose between it getting hot enough to burn your fingers, or spraying water all over the place out of the handpiece. Today I learned a great combination of clever ideas that eliminate the heat, mess and instability of this procedure.
Once Scott had unscrewed the bar, he attached analogs to it replicating the fixtures. The next step in the technique was to inject out bite registration paste and sink the analogs into it, creating a model base for the bar. This base of silicone makes holding on to the bar easier and gives it stability. Lastly he placed the silicone model with the analogs and the bar into one of the red rubber forms we use to base stone models. He explained to me that this way he can use the water on his high-speed to keep things cool, and it is caught by the base former, then he can simply dump the water out in the sink, instead of it spraying all over the operatory floor.
After he had reattached the segments of the bar and connected them with pattern resin and sent it to the lab, Scott laid a flap and exposed the implants. I came in and used our new DEKA Vero CO2 laser and treated the bone and exposed surfaces of the fixtures on the peri-implantitis setting, to decontaminate the implant surface , without heating it up and encourage healing. Although I don’t often have to section and solder a bar that has already been in the mouth, it is a routine part of building these cases and ensuring passivity. So the next time I will be getting out the bite registration paste and a rubber base former to make my life easier.
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