I can't say for sure, but those look like Esco Twist-Lok teeth. Never worked with them myself, and I've only seen them a couple of times. If they are Twist-Lok, they don't have a retainer, they twist a bit of a turn to lock. But I doubt you'd twist them to unlock them. Once those fines get built up in the void between the tooth and the adapter it's Gods Locktite, you'll probably have to burn them off with a gas axe. The problem is finding new ones, they're like trying to find hens teeth. I don't know if it's a discontinued product or what, but they're not easy to find.
BTW, post #7 above, the tooth in the middle, that's an Esco Super V, that's not what your teeth are.