Do implant length and width matter for short dental implants (<10 mm)? A meta-analysis of prospective studies.

Background: This meta-analysis of prospective clinical trials was conducted to determine the effects of dental implant length and width on implant survival rate of short (<10 mm) implants.

Methods: An electronic search of the PubMed database for relevant studies published in English from November 1998 to March 2012 was performed. Selected studies were randomized clinical trials, human clinical trials, or prospective trials with a clear aim of investigating the success or survival rate of short (<10 mm) implants.

Results: Eight studies fulfilled the inclusion criteria and were subsequently analyzed. A total of 525 short (<10 mm) dental implants were analyzed, of which 253 were 3.5 mm in diameter (48.19%), 151 were 4.0 mm (28.76%), 90 were 4.1 mm (17.14%), 21 were 4.8 mm (4%), and 10 were 5.1 mm (1.9%). All implants included in this meta-analysis had a follow-up period of 12 to 72 months. The included studies reported on the survival rate and diameter of the implants. Six of the studies used "short implants" (7 to 9 mm), and the remaining were classified as "extra-short implants" (≤ 6 mm). Five-year estimated failure rates were 1.61% and 2.92%, respectively, for extra-short and short implants (z = -3.49, P <0.001, 95% confidence interval = 0.51% to 4.10%). Furthermore, it was found that the wider the implant, the higher the failure rate (estimated failure rate = 2.36%, 95% confidence interval = 1.07% to 5.23%).

Conclusions: Neither implant length nor width seemed to significantly affect the survival rate of short implants (<10 mm). Nonetheless, further well-designed randomized clinical trials are needed to confirm these findings.