Gum recession can have various causes and requires a specialist visit to understand the causes and see how to treat them.
They can be due to periodontal disease (pyorrhea) which leads to a widespread loss of supporting tissue and are then difficult to treat. They are often caused by the presence of thin gums traumatized by incorrect brushing or due to the movement of the tooth following orthodontic treatment.
They can be corrected with specific surgical techniques and the doctor will advise you on the best one for your case.