This review originally published in 2009 has now had a critical summary of it prepared under the auspices of the American Dental Association Center for Evidence-Based Dentistry
The appraiser considered that this was a good systematic review that had used accepted methods and applied rigourous selection criteria. There was homogeneity among the 5 studies included but they all has small sample sizes and were of short duration.
The limited available evidence indicates that immediately loaded single implants (with crowns) are at higher risk of failure.
Go to the ADA critical Summary
Go to the Pubmed abstract of the original review