The diagnostic process and interdisciplinary treatment of a healthy 12-year-old boy with impactions due to a localized peripheral odontogenic fibroma are presented. The treatment consisted of the surgical excision of the peripheral odontogenic fibroma and interceptive orthodontic treatment with an activator appliance to allow the passive eruption of the impacted teeth. Complete orthodontic treatment with fixed appliances was used later to level and coordinate the arches. This report illustrates the importance of early diagnosis and treatment of tooth impactions associated with diffuse gingival enlargement. The cooperation of various specialists in making a differential diagnosis, developing a comprehensive plan for conservative treatment, and delivering excellent care led to a successful result for this patient.