This document, an inquiry-based curriculum supplement that includes materials for both teachers and students, is designed to develop an understanding among students about oral health. Contents include: (1) "About the National Institutes of Health"; (2) "About the National Institute of Dental and Craniofacial Research"; (3) "Introduction to Open Wide and Trek Inside"; (4) "Implementing the Module"; (5) "Using the CD-ROM"; (6) "Using the Student Lessons"; and (7) "Student Lessons". Lesson plans include: (1) "What Do Mouths Do?"; (2) "Open Wide! What's Inside?"; (3) "Let's Investigate Tooth Decay!"; (4) "What Lives Inside Your Mouth?"; (5) "What Keeps Your Mouth Healthy?"; and (6) "What Have You Learned about the Mouth?" This curriculum supplement contains several activities that can be used in sequence or as individual activities designed to fit into 45 minutes of classroom time. The printed version may be used in isolation or in conjunction with the CD-ROM, which offers video clips, animations, simulations, and interactive games relating to the lesson material presented in the text. Also included in the document are: Additional Resources for Teachers; a Glossary; Masters; and Masters in Spanish. (Contains 13 references.) (YDS)