State of the Art of Short Dental Implants:A Systematic Review of the Literature

Background: Short implants (=8 mm) are manufactured for use in atrophic regions of the jaws. As implant length in many studies has been proven to play a major role in implant survival it is indicated to evaluate survival of short implants in the present literature. Purpose: The purpose of this study was systematically to evaluate publications concerning short dental implants defined as an implant with a length of =8 mm installed in the maxilla or in the mandible with special reference to implant type, survival rate, location of implant site, and observation time. Materials and Methods: A Medline and a hand search were conducted to identify studies concerning short dental implants of length =8 mm published between 1992 and October 2009. The articles included in this study report data on implant length =8 mm, implant surface, registered region of installment, observation time, single tooth restorations, supporting overdentures, splinted implants, and implants used for prostheses. Results: The 27 included studies represent zero randomized clinical trial studies, 15 prospective nonrandomized, noncontrolled clinical trials, 11 retrospective nonrandomized, noncontrolled clinical trials, and one review. Data on 6-mm implants were few and most frequent represented was manufactured Straumann implants representing 441 out of 549 implants. Brånemark implants, 7 mm in length, comprised 1607 implants out of 1808. Straumann implants, 8 mm in length, comprised 2040 out of 2352 implants. Failures varied between 0 and 14.5%, 0 and 37.5% and 0 and 22.9% of the 6-, 7-, and 8-mm-long implants, respectively. Conclusion: Short implant length was not related to observation time, installment region, failures, and dropouts were not specified, subsequently a meta-analysis was not possible to perform.