This narrative review summarizes current scientific evidence on lifestyle and dietary factors associated with dental caries in adolescents. The review focuses on free sugar intake, sugar-sweetened beverages, and complementary determinants such as oral hygiene behaviors and fluoride exposure. Evidence from WHO guidelines and systematic reviews indicates that frequent intake of free sugars is strongly associated with increased caries risk. Preventive strategies targeting healthier dietary habits and consistent oral hygiene are essential during adolescence as a critical period for establishing long-term oral health behaviors.