As mentioned, receding gums are caused by various factors. The most common cause is microbial plaque. Microbial plaque, or dental plaque, is caused by not taking good care of your dental hygiene. Microbial plaque consists of yellow, white and brown layers at the end of the teeth and near the gums. These microbial plaques secrete acidic substances that gradually destroy the surface of the gums, causing gum recession or cavities.