Ans: The specific tiny microbes that live in our mouth, these micros with us soon after birth. We pick them up from our mothers at the infant stages. As our teeth erupt they naturally benign to accumulate communities of bacteria. Depending upon what we eat and specifically how much sugar we consume, certain microbes can overpopulate and cause cavities. Diets high in sugary food causes an explosion of bacteria called mutant streptococci in our mouths. microorganisms love sugar just as the humans, they use this for molecular building blocks and energy sources. As they consume it, the bacteria generate byproducts in the form of acids such as lactic acid. Our mouths are not resistant to acid, unlike the mutants streptococci. While each human tooth is coated in a hardy protective layer of enamel, it is no match for acid. This degrades the armor over time, leaching its calcium minerals. Gradually wears down a pathway for bacteria into the tooth secondary layer called the dentin. Since the blood vessels and nerves in our teeth are enclosed deep within at this stage the expanding cavity doesn’t hurt. If the bacterial damage extends beyond the dentin, the further progression would cause excruciating pain as the nerves become exposed. Without treatment, the whole tooth may become infected and would require removal.