Well, can you send me a snap of patient's mouth to know the exact situation?
Orthodontic treatment included surgery (implant etc., If it is then only done after completion of Ortho treatment. Because implant is the final way of filling the not possible created gap. I.e. extracted tooth due to several decay, loosening of gums which can't hold tooth any more, trauma etc. But implant can be done at any part of life. As old people gets full mouth fixed denture based on implant abutment) periodontal treatment (gums- flap surgery), Endodontic (filling, RCT etc.).
Also apart from braces, a dentist uses external or internal appliances to correct malposition, either skeletal (bone) or dental.
It is a basic rule of Ortho to either create or fill gap. And 1st pre molar is a natural choice. The applied physical forces due to braces (which dentist tighten time to time, and it causes strain Everytime patient visit to dentist but disappear soon) and/or appliances causes tooth to be aligned with desired shape.
Ortho treatment needs several x-rays. Panaromic, lateral, individual (choice of dentist if any defect), CT scan (if any doubt or study) etc. Then dentist study on it. On a transparent paper diagram is drawn. Then strategy is made. And it takes time. From 6 months to few years, depends upon what is goal. Follow instructions of brushing, eating habit (abstain from chocolate, sticky junk food), gargle 3 times at least with antiseptic solution diluted with water, take vitamins, eat raw food etc. Ask dentist about it.