This book begins with the structure of teeth, analyzing the external structures (crowns and roots) and the internal structures (enamel and pulp), explaining their functions in chewing, pronunciation, and maintaining facial aesthetics. It then examines the causes of common problems such as caries (bacterial acid erosion of tooth enamel), periodontitis (plaque-induced inflammation of supporting tissues), and tooth sensitivity (exposed dentin), covering factors such as poor hygiene and improper diet. Finally, it provides daily care methods, dietary recommendations, and key dental care priorities for different age groups. Integrating medical research, this book helps readers prevent dental disease, maintain scientific dental care, and safeguard oral and overall health.