This interrupted case study examines tooth decay and the underlying causes of dental lesions and cavities. “Sini” is a 23-year-old woman seeking relief from oral pain when eating. She also suffers from sensitivity to hot and cold, a condition that has developed over time in the context of poor oral hygiene and excessive soda consumption. Students read and answer questions about Sini’s condition as her dentist discovers severe decay in several of her posterior teeth. The case explores tooth placement and anatomy, the chemistry underlying dental erosion and caries associated with soda consumption, and strategies for preventing cavities. This integrated approach connects concepts from the nervous, digestive, and muscular systems as well as key principles of chemistry to provide a comprehensive understanding of the mechanisms contributing to dental pathology. Designed to be flexible and accessible to a range of learners, the case is appropriate for both lower- and upper-level undergraduate students in anatomy and physiology courses, and is particularly well suited to students with an interest in dentistry or dental hygiene.