Survival rates of short dental implants (≤6 mm) compared with implants longer than 6 mm in posterior jaw areas: A meta‐analysis

• Published in: Clinical oral implants research 2018-10, Vol.29 (S16), p.8-20
• Main Authors: Papaspyridakos, Panos, Souza, Andre, Vazouras, Konstantinos, Gholami, Hadi, Pagni, Sarah, Weber, Hans‐Peter
• Format: Article
• Language: English
• Subjects: Alveolar Bone Loss; Bone implants; Bone loss; Clinical trials; Complications; Databases, Factual; Dental Implantation, Endosseous - adverse effects; Dental Implantation, Endosseous - instrumentation; Dental Implants; Dental materials; Dental Prosthesis Design; Dental prosthetics; Dental Restoration Failure - statistics & numerical data; Dental restorative materials; Dentistry; Failure rates; Heterogeneity; Humans; Identification methods; Jaw; Medical research; Meta-analysis; Patients; Prostheses; Prosthesis Failure; Randomized Controlled Trials as Topic; Risk; short dental implants; Surgical implants; Survival; Survival Analysis; Transplants & implants
• ISSN: 0905-7161; 1600-0501
• DOI: 10.1111/clr.13289

Purpose To systematically review randomized controlled clinical trials (RCTs) reporting on the long‐term survival and failure rates, as well as the complications of short implants (≤6 mm) versus longer implants (>6 mm) in posterior jaw areas. Materials and Methods Electronic and manual searches were conducted to identify studies, specifically RCTs, reporting on short dental implants (≤6 mm) and their survival and complication rates compared with implants longer than 6 mm. Secondary outcomes analyzed were marginal bone loss and prosthesis survival rates. Results Ten RCTs fulfilled the inclusion criteria and featured a total of 637 short (≤6 mm) implants placed in 392 patients, while 653 standard implants (>6 mm) were inserted in 383 patients. The short implant survival rate ranged from 86.7% to 100%, whereas standard implant survival rate ranged from 95% to 100% with a follow‐up from 1 to 5 years. The risk ratio (RR) for short implant failure compared to standard implants was 1.29 (95% CI: 0.67, 2.50, p = 0.45), demonstrating that overall, short implants presented higher risk of failure compared to longer implants. The heterogeneity test did not reach statistical significance (p = 0.67), suggesting low between‐study heterogeneity. The prosthesis survival rates from the short implant groups ranged from 90% to 100% and from 95% to 100% for longer implant groups, respectively. Conclusion Short implants (≤6 mm) were found to have higher variability and lower predictability in survival rates compared to longer implants (>6 mm) after periods of 1–5 years in function. The mean survival rate was 96% (range: 86.7%–100%) for short implants, and 98% (range 95%–100%) for longer implants. Based on the quantity and quality of the evidence provided by 10 RCTs, short implants with ≤6 mm length should be carefully selected because they may present a greater risk for failure compared to implants longer than 6 mm.