Insufficient evidence for sinus lifts over short implants for dental implant rehabilitation

The Cochrane Oral Health Group's Trials Register, Cochrane Central Register of Controlled Trials (CENTRAL), Medline and Embase databases were searched with no language or date restrictions.

Two reviewers independently selected studies. Randomised controlled trials (RCTs) of different techniques and materials for augmenting the maxillary sinus for rehabilitation with dental implants that reported the outcome of implant success or failure at least four months after initial loading were considered.

Data were extracted independently by two reviewers and study risk of bias assessed. Results were expressed using fixed-effect models as there were either fewer than four studies or we used Peto odds ratios (ORs) for dichotomous data when there were zero cells in either the treatment or control or both arms and the number of trials was small.

Eighteen trials involving 650 patients were included. Five studies were considered to be at low risk of bias, 11 at high risk and two of unclear risk. Four trials (102 patients) evaluated short implants (5 to 8.5 mm long) as an alternative to sinus lift in bone with residual height between 4 and 9 mm. One year after loading there was insufficient evidence to claim differences between the two procedures for prosthesis failure (OR (Peto) 0.37, 95% confidence interval (CI) 0.05 to 2.68; three trials) or implant failure (OR (Peto) 0.44, 95% CI 0.10 to 1.99; four trials). There was however an increase in complications at treated sites when undertaking the sinus lift (OR (Peto) 4.77, 95% CI 1.79 to 12.71, P value = 0.002; four trials).Fourteen trials (548 patients) compared different sinus lift techniques. Only three comparisons included more than one trial. These were bone graft versus no bone graft, autogenous bone versus bone substitute, bone graft with or without platelet-rich plasma (PRP). There was insufficient evidence to claim a benefit for any of these techniques for the primary outcomes of prosthesis and implant failure.The other comparisons with single studies were rotary versus piezosurgery to open a lateral sinus window, two different bone substitutes, use or not of a membrane to seal the lateral window, one- versus two-stage lateral sinus lift, two-stage granular bone versus one-stage autogenous bone blocks and crestal versus lateral sinus lift; two trials compared three different crestal sinus lifting techniques: rotatory versus hand malleting (patients preferred rotatory instruments over hand malleting) and hand versus electric malleting. There was no evidence of a benefit for any sinus lift procedure compared to any other for the primary outcomes prosthesis or implant failure.

There is moderate quality evidence which is insufficient to determine whether sinus lift procedures in bone with residual height between 4 and 9 mm are more or less successful than placing short implants (5 to 8.5 mm) in reducing prosthesis or implant failure up to one year after loading. However, there are more complications at sites treated with sinus lift procedures. Many trials compared different sinus lift procedures and none of these indicated that one procedure reduced prosthetic or implant failures when compared to the other. Based on low quality evidence, patients may prefer rotary instruments over hand malleting for crestal sinus lift.