There are many reasons teeth become crowded. Sometime crowed teeth can cause periodontal disease due to difficulty in cleaning. Periodontal disease can causes bone lost. Lost of tooth structure from decay can also cause teeth to be crowded. Other reasons can be poor tongue position, mouth breathing, biting objects like finger nail,
Modern orthodontic technique can correct many of these crowding problems. After teeth are aligned, flossing teeth can be easier and teeth keep clean longer.