The classification of traumatic dental injuries can involve teeth, supporting structures, or gingival and oral mucosa. The therapeutic use of lasers has become standard practice in many medical fields, but dental traumatology is not yet one of them. This case report relates dental trauma of a 36-month-old girl referred to the Dental Trauma Center for Children and Adolescents in a University dental clinic (Brazil). Her fall down the stairs at home resulted in face trauma, avulsion of a primary incisor and soft tissue injuries. The mother reported pain and inflammation of the lacerated lip. After examination, a low-level laser was applied to ulcerated lip and gingival tissues. The protocol was punctual and continuous application at 660nm, 1J/point every 48 hours. The low-level laser biomodulation capacity provided complete tissue healing after 14 days of sessions. Clinical trials are suggested. Conservative treatment in this case of severe soft-tissue injuries into a baby showed a clinically satisfactory result. Minimal intervention was also important to minimize possible psychological side effects of surgical dental therapy. Low-level lasers are an excellent alternative therapy for children, because of their analgesic/anti-inflammatory and biomodulatory effects.