Distraction osteogenesis and tissue engineering--new options for enhancing the implant site

In severe atrophy of the mandible, implant placement in original bone may not be possible. In this field, augmentation procedures have already been described and controversially discussed. By the use of distraction osteogenesis, bone augmentation without donor morbidity is obtained, while the implant-bone interface remains in original bone. Despite soft tissue expansion during the distraction process, a lack of attached gingiva may cause difficulties at the implant site. In certain cases, an additional soft tissue augmentation procedure has to be performed for a good long-term functional and esthetic rehabilitation. The connective tissue graft and the free gingival graft are recommended to be standard procedures to create a stable periimplant mucosa, but the morbidity and the size limitation of the donor site have to be taken into consideration in selected patients. Transplantation of in vitro-cultured keratinocytes could be an alternative. Distraction osteogenesis and tissue engineering of keratinocytes, as well as bone-cultivating techniques, may increasingly be valuable adjuncts to current augmentation procedures.