The black on your teeth is decay. Cavities/decay turn from yellow to brown to black as it continues to develop for a long period of time. Decay is caused by bacteria that is already in the oral cavity that feeds itself from remnants of sugar and carbohydrates that we consume on a daily basis.The lack of regular brushing and floossing would allow the bacteria to continue to grow to a level that is harmful to your health. Depending were the decay first develop in your mouth and its proximity to the sinus, it could become very sirius if bacteria invades the brain. you can also develop Bacterimia which refers to bacteria in your blood stream and of course once in your blood stream you could develop infections that would affect vital organs in your body, the Heart been the most commonly affected.

Jenny Nunez-Davenport