Background: To minimize the risk of implant failure, osseointegrated oral implants are conventionally kept load-free during the healing period. During healing removable prostheses are used, however many patients find these temporary prostheses rather uncomfortable and it would be beneficial if the healing period could be shortened without jeopardizing implant success. Nowadays immediate and early loaded implants are commonly used in mandibles of good bone quality. It would be useful to know whether there is a difference in success rates between immediately or early loaded implants compared with conventionally loaded implants.
Objectives: To test the null hypothesis of no difference in the clinical performance between osseointegrated implants loaded at different times 1 year after loading.
Search strategy: The Cochrane Oral Health Group's Trials Register, The Cochrane Central Register of Controlled Trials, MEDLINE and EMBASE were searched. Handsearching included several dental journals. Authors of all identified trials, an internet discussion group and 55 oral implant manufacturers were contacted to find unpublished randomized controlled trials (RCTs). The last electronic search was conducted on 2 February 2004.
Selection criteria: All RCTs of root-form osseointegrated oral implants having a follow up of at least 1 year comparing the same osseointegrated root-form oral implants loaded at different times.
Data collection and analysis: Data were independently extracted, in duplicate, by two reviewers. Authors were contacted for details of randomization and withdrawals and a quality assessment was carried out. The Cochrane Oral Health Group's statistical guidelines were followed.
Main results: Seven RCTs were identified and five trials including 124 patients in total were suitable for inclusion. Implants have been either immediately loaded after insertion (2 to 3 days), early loaded (6 weeks) or conventionally loaded (3 to 8 months) in edentulous mandibles of adequate bone quality and shape. On a patient, rather than per implant basis, there were no statistically significant differences for prosthesis failures, implant failures and marginal bone loss on intra-oral radiographs.
Reviewers' conclusions: While it is possible to successfully load oral implants immediately after their placement in mandibles of adequate bone density and height of carefully selected patients, it is yet unknown how predictable this approach is. More well designed RCTs are needed to understand how predictable immediate and early loading are. Such trials should be simply designed and should be reported according to the CONSORT guidelines (http://www.consort-statement.org/). It is suggested that priority should be given to trials assessing the effectiveness of immediately loaded implants rather than early loaded ones.