ActionScript 3.0 :: Array Vs Object Speed?

I have a little utility takes lists of letters, combines them in every possible permutations, and lists out all the combinations that are words. For example, I would feed it in "cde,abc,tbrn" and it would let me know that cat, cab, car, can, dab, eat, ear, and ebb are all valid words.I've tried two different approaches: Load a dictionary text file, and splice it into dict:Array. For each possible letter combination run:

if(dict.indexOf(testWord)!=-1) trace(testWord);
The other option is to convert dict:Array into an dictionary:Object
for (i=0; i<dict.length; i++){dictionary[(dict[i])] = dict[i];}

and then run:
if(dictionary[testWord]) trace(testWord);

Although I've read arrays are faster than objects, testing to see if the word exists in an object, and iterating 10s to 100s of times over a several thousand word dictionary is orders of magnitude faster than checking to see if the word exists in the dict:Array.