Paul Coulthard, Marco Esposito, Helen V Worthington, Asbjorn Jokstad

Preprosthetic surgery refers to the surgical procedures that can modify the oral anatomy to facilitate the retention of conventional dentures. Osseointegrated implants offer an alternative treatment to improve denture retention. A denture may be connected by special attachments to implants placed into the jaw. To test the null hypothesis of no difference in the success (patient satisfaction and morbidity) and cost effectiveness between conventional prostheses that require preprosthetic surgery (PPS) and implant retained prostheses (IRO) that do not require preprosthetic surgery, against the alternative hypothesis of a difference. The Cochrane Oral Health Group Trials Register (May 2002), CENTRAL (The Cochrane Library 2002, Issue 2), MEDLINE and EMBASE (May 2002) were searched. In addition, 55 implant companies were contacted and the bibliographies of review articles were checked for studies outside the hand searched journals and personal references were searched. Randomised controlled trials (RCTS) comparing preprosthetic surgery and implant retained dentures for improving denture retention. Data were independently extracted, in duplicate, by two review authors. Authors were contacted for details of randomisation and withdrawals and a quality assessment was carried out. The Cochrane Collaboration's statistical guidelines were followed. One study, containing 60 participants, reported in four articles was identified for inclusion in this review. No studies were excluded. There was a statistically significant difference between mean patient satisfaction scores with patients in the IRO group being more satisfied in general at both year 1 (WMD = -0.66 (95% CI -1.28 to -0.04)) and 5 years (WMD = -0.90 (95% CI -1.74 to -0.06). Altered sensation of the lower lip and chin was measured at 1 year and 5 years. There was no statistically significant difference at either time point and no patients had altered sensation at 5 years. There is weak evidence from the results of one randomised controlled trial including 60 subjects that patients are generally less satisfied with preprosthetic surgery and a conventional denture than with an implant retained denture. There is a need for more well designed trials comparing the success and cost-effectiveness of preprosthetic surgery and implant supported dentures. Such trials should be reported according to the CONSORT guidelines (www.consort-statement.org/). However, since preprosthetic surgery is considered to be an obsolete treatment nowadays, almost completely replaced by dental implants, it may be that new RCTs on this topic will not be designed.