Dental plaque is a filmy deposit on teeth consisting of mucus, bacteria, food and other particles. It can lead to tooth decay, a process where enamel and dentin are demineralized and destroyed, potentially causing cavities. Factors that increase decay risk include foods high in sugar, poor oral hygiene, smoking, dry mouth and Sjogren's Syndrome. Decay happens when acids from plaque dissolve enamel. Dentists can detect decay through examining teeth for soft areas, probing with instruments, and taking dental x-rays to view the extent of cavities.