The scientific basis for dental implant therapy.

Dental and oral implantology have rapidly moved into the mainstream of dentistry in the last ten years with a phenomenal growth based on rapidly expanding technology, increasing public interest, and the reporting of sound scientific data. This paper reviews current knowledge about implant tissue reactions and identifies areas where additional scientific inquiry is needed. Bone- and soft-tissue healing around dental implants varies greatly depending upon the form of the implant, biomaterial used, and surgical approach. Controversy exists as to whether a direct bony-biomaterial interface is preferable over a bone-connective tissue-biomaterial interface. Scientific data are required to document whether intervening molecular layers of glycoproteins exist between implant and bone, and what role is played by these structures relative to the implant-bone interface. The adaptation of regenerated gingival epithelium to an implant is critical for the development of a perimucosal seal. Many scientific questions remain unanswered about this seal and its role in maintenance of implant longevity. Controlled clinical trials must be carried out to determine clinical serviceability standards for patients. Resolving these areas of concern and understanding the biological reactions involved will require in-depth scientific inquiry by clinician and scientist alike to make dental implantology a highly acceptable and predictable treatment modality. Even with these controversies and lack of comprehensive comparison studies, dental implantology is an exciting treatment concept that makes considerable demands upon the surgical, prosthetic, periodontal, and restorative skills of today's practitioners, and on their scientific understanding as well.