It is important that you know how to brush your teeth properly to prevent conditions such as gingivitis and tooth decay. Incorrect brushing technique can also lead to tooth abrasion, a condition in which the surface of the tooth is worn away. The number one cause of tooth abrasion is from a toothbrush. The delicate gum tissue is also at risk for damage from the toothbrush bristles, causing tooth sensitivity from exposed root surfaces. Follow these instructions, and learn how to brush your teeth properly.