The Dentacoin (DCN) token represents an extended version of an ERC-20 contract. The token is available with several exchange platforms. At the moment of writing, you can trade DCN against two fiat currencies (EUR and USD) with Folgory exchange.
Emercoin (EMC) is the mineable coin based on the Emercoin’s own blockchain. You can convert these coins to other cryptos and back on a few exchanges. Emercoin was launched as early as in 2013 as the Peercoin’s fork.