Tooth decay is at the same time inevitable and preventable. It's inevitable because everyone has a natural population of oral bacteria that cling to unclean teeth surfaces and form a sticky substance called plaque. Left alone, the plaque hardens into tartar. Byproducts of plaque literally eat away at the tooth's various layers, working from the external enamel to the internal, sensitive pulp layer. Of course, once this tooth decay process has begun, there's no solution other than to remove the existing decay, fill the space, and seal it against further problems. However, the entire situation is also highly preventable. Twice daily brushing and careful flossing can remove most of the naturally occurring plaque, and dental sealants can prevent the buildup of plaque in the grooves on top of teeth. Regular professional cleanings will eliminate tartar as well.