Bacteria and plaque build-up cause acid formation which is what starts the process of tooth decay. The acid slowly erodes the protective layer of tooth called enamel. Once the outer enamel layer is broken, the decay spreads through the software layer called the dentin. If the decay expands through dentin, it can damage the internal root. This may require additional treatment to extract the infected tissues. Early detection and treatment of tooth decay is important to prevent further complications. Regular visits to the dentists coupled with maintaining oral hygiene can reduce these problems.