According to Anthony Diodati :
Could the short have opened up a connection/splice somewhere?

It _could_, but dimmer triacs are MUCH more sensitive to high overloads
than house wiring. Semi-conductors (even power devices) are excellent
"very very fast blow" fuses on high overloads. They can blow in
microseconds, whereas breakers take considerably longer even in the highest
of overloads.

If you get a short on a dimmer controlled device, even a momentary one,
chances are that the dimmer is dead even if the breaker doesn't trip.
Indeed, I'm a little surprised that the breaker _did_ trip. Somehow
that triac held the current high long enough for the breaker to notice...

[Likely the junction in the triac vaporized and maintained conductivity
just long enough for the breaker to start moving. Then the conductivity
failed when the vapors condensed.]

When I saw "nonfunctional", "short circuit" and "dimmer", "fried dimmer"
is the conclusion I immediately jumped to. The breaker tripping was
essentially irrelevant in determining the most likely cause.

The idea course of action is to test the dimmer ("Do I have good voltage
on the input and not the output?"), but, without some knowledge and proper
instrumentation (a high impedance voltmeter isn't it), swapping
the dimmer (or simply taking it out of the circuit temporarily) is
probably easiest for most people.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.