The clinical performance of narrow diameter implants versus regular diameter implants: A systematic review and meta-analysis.

The purpose of the study is to analyze the 1-year and 3-year clinical performance of NDIs compared with RDIs.An electronic search from electronic databases and a hand search was performed from inception to April 2018. A meta-regression was used to evaluate the effects of the "fixed effects" model on the implant survival, prosthesis success rates and marginal bone loss with follow-up time of 1 year and 3 years. Of the 11 studies included, The overall pooled 1-year implant survival rates were 98.14% for NDIs and 98.20% for RDIs. The overall pooled 3-year implant survival rates were 98.71% for NDIs and 98.84% for RDIs. The corresponding values for 1-year prosthesis success rates were 96.94% for NDIs and 99.25% for RDIs. The corresponding values for 3-year prosthesis success rates were 89.25% for NDIs and 96.55% for RDIs. The meta-regression showed that no significant difference between narrow diameter implants and regular diameter implants in implant survival rates, prosthesis success rates and marginal bone loss(MBL) in 1-year and 3-year follow-up (P > 0.05). This meta-analysis concluded that the diameter of the implant did not affect its survival, prosthesis success rates and MBL in 1 and 3 years. The use of a narrow diameter implants instead of bone augmentation procedures with regular diameter implants does not affect its survival, prosthesis success rates and marginal bone loss in a short-term and a middle-term. However,more high-quality RCTs and long follow-up studies are needed on this topic.