Background: Dental implants are available in different materials, shapes and with different surface characteristics. In particular, numerous implant surface modifications have been developed for enhancing clinical performances.
Objectives: To test the null hypothesis of no difference in clinical performance between various root-formed osseointegrated implant types.
Search strategy: The Cochrane Oral Health Group Specialised Trials Register, The Cochrane Controlled Trials Register, MEDLINE and EMBASE were searched. Hand searching included several dental journals. Bibliographies of relevant clinical trials and review articles were checked for studies outside the handsearched journals. In addition, authors of all identified trials and fifty-five oral implant manufacturers were contacted to find unpublished or ongoing RCTs. Two extensive personal libraries (ME and AJ) were consulted. The last electronic search was conducted 8th May 2002.
Selection criteria: All randomised controlled trials of oral implants comparing implants with different materials, shapes and surface properties having a follow-up of at least one year.
Data collection and analysis: Data were independently extracted, in duplicate, by two reviewers (ME & HW). Authors were contacted for details of randomisation and withdrawals and a quality assessment was carried out. The Cochrane Oral Health Group's statistical guidelines were followed.
Main results: Thirty publications, representing 13 different RCTs, were identified. Five of these RCTs (seven publications), which reported results from a total of 326 patients, were suitable for inclusion in the review. Six implant systems were compared: Astra, Branemark, IMZ, ITI, Steri-Oss and Southern with a follow-up ranging from one to three years. All implants were made in commercially pure titanium and had different shapes and surface preparations. On a patient rather than per implant basis there were no statistically significant differences for failures and marginal bone level changes on intra-oral radiographs between various implant systems.
Reviewer's conclusions: There was no evidence that any of the implant systems evaluated was superior to the other. However, these findings are based on a few RCTs all having short follow-up periods and few participants. More RCTs should be conducted, with follow-up of at least five years and including a sufficient number of patients, to detect a true difference if any exists. Such trials should be reported according to the CONSORT guidelines (http://www.consort-statement.org/).