Format of Original
Nature Publishing Group (Macmillan Publishers Limited)
The Cochrane Oral Health Group's Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), Medline, and Embase databases were searched. Reference lists of identified articles were also scanned for relevant papers. There were no restrictions on language or date of publication.
Randomised controlled trials (RCTs) of parallel group design and of split-mouth design including root-form osseointegrated dental implants having a follow-up of four months to one year after loading were included.
Data extraction and synthesis
Data were independently extracted, in duplicate, by at least two review authors. The outcome measures were prosthesis and implant failures and radiographic marginal bone level changes. Risk of bias was assessed for each trial by at least two review authors. Results were combined using fixed-effect models with mean differences (MD) for continuous outcomes and risk ratios (RR) for dichotomous outcomes with 95% confidence intervals (CI).
Twenty-six trials involving a total of 1217 participants and 2120 implants were included. The risk of bias was low in three trials, high in 12 and unclear for the remaining eleven. In nine studies there were no prosthetic failures within the first year, with no implant failures in seven studies and the mean rate of implant failure in all 26 trials was a low 2.5%. From 15 RCTs comparing immediate with conventional loading there was no evidence of a difference in either prosthesis failure (RR 1.87; 95% CI 0.70 to 5.01; 8 trials) or implant failure (RR 1.65; 95% CI 0.68 to 3.98; 10 trials) in the first year. However, there is some evidence of a small reduction in bone loss favouring immediate loading (MD -0.10 mm; 95% CI -0.20 to -0.01; P = 0.03; 9 trials), but this very small difference may not be clinically important. From three RCTs which compared early loading with conventional loading, there is insufficient evidence to determine whether or not there is a clinically important difference in prosthesis failure, implant failure or bone loss. Six RCTs compared immediate and early loading and found insufficient evidence to determine whether or not there is a clinically important difference in prosthesis failure, implant failure or bone loss. From the two trials that compared occlusal loading with non-occlusal loading there is insufficient evidence to determine whether there is a clinically important difference in the outcomes of prosthesis failure, implant failure or bone loss. No trials were identified which evaluated progressive loading of implants.
Overall there was no convincing evidence of a clinically important difference in prosthesis failure, implant failure or bone loss associated with different loading times of implants. More well-designed RCTs are needed and should be reported according to the CONSORT guidelines.