[Packard]

Confirmats seem to work best. They offer decent pullout strength and improved racking strength. It requires a special drill bit. They behave like both screws and dowels. Never place any fastener in the edge of MDF (or particle board or plywood) less than 2" from the corner.

AH Turf and McFeely's both sell them. McFeely's has a starter kit with screws and stepped drill bit included.

I agree with Steve, dowels seem to be a better choice. Even biscuits might be a better choice. Dowels offer more racking strength than biscuits.