It's difficult to reply to your question as asked. It's not clear exactly what you're asking, and your objective is also questionable. Here's my advice, with a little more information than you might want to hear, but it will help you understand why I suggest what I do.
Dental gold will usually contain platinum group metals, primarily platinum and palladium. Some are free of them, but you rarely encounter them. Impact fillings are an example.
The Pt group metals are used to toughen the gold, so they're essential to the product. These alloys usually contain at least a little silver as well, so you're in a situation where in order to effectively recover the platinum group, you have to operate a silver parting cell. Otherwise you have to deal with silver chloride on a regular basis, and even that won't accomplish the necessary separation to satisfaction. Silver readily becomes a carrier of the platinum group metals, and alters the behavior of platinum in that in the presence of silver, it will partially dissolve. Like it or not, you end up with platinum in your silver.
If you have a small amount of dental gold, my advice would be to process it front to back so you become familiar with the steps involved. Learning on large volumes can be a serious mistake in that you're likely to be somewhat clumsy with these things at the outset, perhaps breaking a container or doing something stupid that complicates recovery. It's far better to risk small amounts until you fully understand what you're doing.
Inquart your dental gold, assuming it is, at a minimum, 16K, part with nitric, then use AR to refine the gold. Recover the inquarted silver using copper bars, not wire. Save all your solutions, and test them for Pt group content. You can precipitate those traces using copper, or you can simply pour the entire lot on scrap steel, which will recover everything of value. What that does for you is to concentrate the values until you have enough to run them as a larger batch. You'll come to learn that the platinum group won't precipitate from dilute solutions well, if at all. It's actually rare to get a complete precipitation, so you find yourself recycling the solutions regularly.
Take it a step at a time, starting with small amounts. Don't toss anything until you know the values have been removed------and you won't get in trouble. Remember-------if everything goes south and you are having a lot of trouble with a process, you can always dump the lot in a plastic bucket with scrap steel and make a complete recovery. It's a wonderful way to recover things when you get in trouble, or when you have traces of values that won't respond to anything else.
Hope this helps. If you have specific questions, fire away.
Harold