Impact of dental implant length on early failure rates: a meta-analysis of observational studies

Aim: To test the null hypothesis of no difference in failure rates of short (minimum length: 7 mm) and longer dental implants (>= 10 mm), a meta-analysis was performed on prospective observational trials. Materials and Methods: A systematic electronic and hand search was performed to identify eligible studies. Having additional data supplied by the authors, 54 publications were included (19,083 implants). Results: In case of mandibular implants, the null hypothesis of no impact of reduced implant length on failure within the first year of prosthetic loading could not be rejected. A significant impact of implant length could be substantiated for short machined implants in the anterior [odds ratio (OR) 5.4] and posterior maxilla (OR 3.4), while short rough-surfaced implants demonstrated increased failure rates in the anterior maxillary sites. No influence of implant diameter and denture type on the failure rate of short implants could be revealed. Conclusion: In areas of reduced alveolar bone height the use of short dental implants may reduce the need for invasive bone augmentation procedures.