Braces. Yes. Even if the tooth erupts, it probably will not come out correctly aligned and this could affect the bite.
Which tooth. Most commonly impacted tooth is wisdom tooth, and this problem is treated with oral surgery. Any other impacted tooth usually requires a combination of braces and localized surgery to make room for the impacted tooth, placement a handle on the tooth, and bringing the tooth into optimum alignment/function. See a qualified Orthodontic Specialist for advice (initial exam usually free or low cost).