OBJECTIVE: The purposes of this investigation were to study the feasibility of placing endosseous implants in children and adolescents with ectodermal dysplasia and to assess the position and stability of such implants during growth. This article reports on 6 subjects with long-term follow-up. Study design. A prospective study was commenced in 1991. Patients with hereditary ectodermal dysplasia who were over the age of 5 years and who presented to the University of California San Francisco Ectodermal Dysplasia Clinic for dental treatment were included and maintained in the study. In each case, clinical and radiographic records were obtained before treatment, immediately after implant placement, at delivery of the prosthesis, and subsequently at yearly intervals. Six subjects are reported, 4 as members of the prospective study group and 2 who had been treated before the study began. RESULTS: A total of 41 implants (19 maxillary, 22 mandibular) were placed. The average follow-up after implant placement was 7.8 years (range, 6-11 years), and the average time since restoration was 6 years (range, 5-10 years). Forty implants successfully integrated and have been restored. There was no evidence that implant placement or prosthetic rehabilitation resulted in restriction of transverse or sagittal growth. One mandibular implant, placed in a partially dentate 5-year-old, became submerged because of adjacent alveolar development and required placement of a longer abutment. Four maxillary implants placed in a partially dentate 7-year-old also became submerged and required prosthetic revision and the placement of longer abutments. CONCLUSIONS: This preliminary report suggests that endosseous implants can be successfully placed and can provide support for prosthetic restoration in patients with hereditary ectodermal dysplasia. However, vertical dentoalveolar growth results in submergence of the implant relative to the adjacent natural dentition when implants are placed adjacent to erupting permanent teeth.