Many talents and feats require a target that is flat-footed, others state that the target loses their dexterity bonus to Reflex defense. To my group's understanding they were the same thing but there is no confirmation of this anywhere. An argument can be made if interpreted as written, that a creature losing its dex to reflex doesn’t necessarily mean it is flat footed. Anyone knows?
They are different mechanics
Those two mechanics are confusing even since they first appeared on the d20 edition of the game. But, to put simply, they are two different mechanics. From the core rulebook, here is a list of conditions and effects that apply either of those.
Denied Dex to Reflex:
- Pin: target can take no actions and is denied Dex to Reflex
- Deceptive Shot (Gunslinger): with successful Deception check, target is denied Dex to Reflex against your attacks until start of your next turn
- Helpless: not only are you denied Dex to Reflex, but "in fact" you have a Dex of 0, so you take a -5 penalty to your base Reflex
- Unaware of attacker: if you are flat-footed or otherwise unaware of your attacker outside of the surprise round, you are denied Dex to Reflex (see "Dexterity Modifier" under the definition of Reflex Defense on pg 145) mind trick: one use is to perform a "feint" that merely denies your target its Dex to Reflex (instead of making it fully flat-footed like feinting normally does) for the next attack you make against it
- Blinded: if you are blinded, you take a -2 penalty to Reflex and are denied Dex to Reflex plus a few other things Climbing: while climbing, you lose Dex to Reflex and opponents get +2 to attack you Running: while running, you lose Dex to Reflex (see Endurance skill, pg 66)
- Surprised: if you are caught unaware at the start of a battle, you cannot act during the surprise round and are flat-footed until your first turn
- Feint: with a successful Deception check vs Will (standard action), your target is flat-footed for the next attack you make against it on your next turn
- Balancing: you are flat-footed while balancing unless you are trained in Acrobatics
- Trákata (Jedi Knight talent): Deception to Feint as 2 swift actions instead of a standard action.
The flat-footed condition does not just deny Dex to Reflex, it also prevents the subject from using free actions (which includes talking) and any abilities that specify that they can't be used while flat-footed (such as Block and Deflect).