The single-word comparative and superlative forms wronger and wrongest are no longer in common use, except humorously; rather, the locutions “more wrong” and “most wrong” are preferred.
When wrong is used attributively, before a noun, the noun is usually treated as definite, using the article the; hence, for example, one says, “I dialed the wrong number”, “he gave the wrong answer”, and “she took the wrong approach”, even though there are many possible wrong numbers, answers, and approaches, of which only one was dialed, given, or taken.