Treatment of lower second premolar agenesis by autotransplantation: four-year evaluation of eighty patients.

The frequency of agenesis of the second lower premolar is 2.5-4%. In growing patients, early extraction of the deciduous molar and subsequent closure of the space is a common therapy, but in some cases space closure is deemed unlikely and autotransplantation is an alternative. The aim of the study was to analyze the outcome of autotransplantation in replacing missing lower second premolars and to evaluate the associated presurgical orthodontic treatment. The material consisted of records of all patients with teeth transplanted to the lower second premolar region during the period 1988-89 at the Department of Oral Surgery, Eastman Institute, Stockholm. The following variables were registered: sex, age, number of transplanted teeth, donor tooth, root development, recipient site, orthodontic treatment, persisting temporary molar, total number of congenitally missing teeth, the surgeon responsible, and clinical and radiological follow-up variables. Of 110 transplanted teeth, 99 had not completed root formation, and in 11 teeth the root formation was completed. The success rates after 4 years were 92% and 82%, respectively. Both premolars and molars served as donor teeth, but the main donor tooth was the upper second premolar. Fourteen percent had been orthodontically treated only because of the transplantation, i.e. to open the space for the donor tooth. Treatment of agenesis of the second lower premolar by autotransplantation has a good prognosis. In growing individuals the transplant not only maintains growth and development of the alveolar ridge but also provides a permanent solution to the agenesis.