Removable plates can be used from early childhood to guide the alignment of the teeth while they are still growing. If they are worn as the orthodontist prescribes, the end result should be well-aligned teeth and properly developed jaws. I wouldn't say we can expect perfect alignment of the teeth with plates. Some minor irregularities may not be resolved, but they often go unnoticed by the patient.
This answer is for general information. Your own case needs an examination by an orthodontist.