Abstract
Selection Criteria
Data sources
Electronic searching was performed in MEDLINE, EMBASE, and Cochrane Library databases through November 2015. The reference lists of the retrieved articles were handsearched as a secondary reference source.
Study selection
Titles and abstracts of the identified articles were screened independently by the authors. Disagreements were resolved by discussion. The inclusion criteria included randomized controlled trials; studies that included the survival rate of implants, complications, and other detailed data regarding implant lengths, diameters, locations, and surgical techniques; and evaluations with a mean follow-up period of at least 1 year. Non-English language articles and articles with insufficient information on prognosis were excluded.
Data extraction and synthesis
Data were extracted by the authors. Risk of bias was assessed based on the recommendations from the Cochrane Handbook of Systematic Review of Interventions. The survival rates and complications of short and control implant groups were the primary outcomes to be extracted and analyzed by meta-analysis. Surgical times and costs were the secondary outcomes. All individual outcomes were pooled by using RevMan5.3. Risk ratio (RR) was used to summarize dichotomous outcomes; all measures of effect were presented with 95% confidence intervals (CIs). The outcomes were aggregated and analyzed by using a random-effect model or fixed-effect model, depending on heterogeneity analysis.
Key Study Factor
Implant length (standard and short), posterior atrophic maxilla (partial or complete edentulousness).
Main results
Seven randomized controlled trials (RCTs) that met the inclusion criteria included 554 implants (265 implants in the short implant group). There was no statistically significant difference in survival rate between 2 groups (RR: 1.00; 95% CI: 0.97-1.03; P = .96). Compared with the long implant group, the short implant group had significantly fewer complications (RR: 0.58; 95% CI: 0.37-0.90; P = .02).
Conclusion
The authors concluded that there is no difference between the survival rates of short implants (5-8 mm) and long implants (> 8 mm); complication rates are lower for short implants than for long implants.