title: Systematic review and meta-analysis of randomized controlled trials for the management of limited vertical height in the posterior region: short implants (5 to 8 mm) vs longer implants (> 8 mm) in vertically augmented sites.
abstract: OBJECTIVE
  The aim of this study was to undertake a systematic review with meta-analysis on randomized controlled trials (RCTs) to compare the rates of survival, success, and complications of short implants to those of longer implants in the posterior regions.
  
  
  METHODS
  Electronic literature searches were conducted through the MEDLINE (PubMed) and EMBASE databases to locate all relevant articles published between January 1, 1990, and April 30, 2013. Eligible studies were selected based on inclusion criteria, and quality assessments were conducted. After data extraction, meta-analyses were performed.
  
  
  RESULTS
  In total, 539 dental implants (265 short implants [length 5 to 8 mm] and 274 control implants [length > 8 mm]) from four RCTs were included. The fixed prostheses of multiple short and control implants were all splinted. The mean follow-up period was 2.1 years. The 1-year and 5-year cumulative survival rates (CSR) were 98.7% (95% confidence interval [CI], 97.8% to 99.5%) and 93.6% (95% CI, 89.8% to 97.5%), respectively, for the short implant group and 98.0% (95% CI, 96.9% to 99.1%) and 90.3% (95% CI, 85.2% to 95.4%), respectively, for the control implant group. The CSRs of the two groups did not demonstrate a statistically significant difference. There were also no statistically significant differences in success rates, failure rates, or complications between the two groups.
  
  
  CONCLUSIONS
  Placement of short dental implants could be a predictable alternative to longer implants to reduce surgical complications and patient morbidity in situations where vertical augmentation procedures are needed. However, only four studies with potential risk of bias were selected in this meta-analysis. Within the limitations of this meta-analysis, these results should be confirmed with robust methodology and RCTs with longer follow-up duration.
authors.forename: Sung-Ah
authors.initials: SA
authors.lastname: Lee
authors.forename: Chun-Teh
authors.initials: CT
authors.lastname: Lee
authors.forename: Martin M
authors.initials: MM
authors.lastname: Fu
authors.forename: Waiel
authors.initials: W
authors.lastname: Elmisalati
authors.forename: Sung-Kiang
authors.initials: SK
authors.lastname: Chuang
mesh_terms: D000540:Alveolar Ridge Augmentation; D015921:Dental Implants; D017267:Dental Prosthesis Design; D006801:Humans; D016032:Randomized Controlled Trials as Topic; D016019:Survival Analysis; D016896:Treatment Outcome
chemical_list: D015921:Dental Implants