Final answer:
Gingival recession is caused by a progressive gum disease called periodontitis, which can develop from untreated gingivitis. As the gums recede, parts of the tooth below the crown are exposed, allowing bacteria to grow and cause further damage.
Step-by-step explanation:
Gingival recession is caused by a progressive gum disease called periodontitis. This disease is typically preceded by gingivitis, which is characterized by inflammation and bleeding of the gums. If gingivitis is left untreated, it can progress to periodontitis, where the gums recede and expose parts of the tooth below the crown. Bacteria can then grow on this exposed area, leading to further damage and potentially tooth loss.