The authors concluded that for dental implants placed in grafted maxillary sinuses, bone substitutes reduced donor-site morbidity and that implants with a textured surface may improve outcome in any graft type. Also, long-term studies are needed to assess non-autogenous grafts. The conclusions need to be interpreted with caution due to lack of validity assessment and possible inappropriate pooling of data.

To evaluate the survival rates of dental implants placed in grafted maxillary sinuses.

MEDLINE (1986 to February 2007), EMBASE (1988 to February 2007) and the Cochrane Oral Health Group Specialized Trials Register (up to February 2007) were searched for studies in all languages. Search terms were reported. Seven international journals in the field of implant dentistry and oral and maxillofacial surgery were handsearched (from 1986 to 2007). The bibliographies of the most relevant papers and review articles were examined for further studies.

Studies in which a lateral approach to the maxillary sinus was used (either the Caldwell-Luc technique or lateral swing door technique of Tatum) and at least 20 sinus augmentations were carried out were eligible for inclusion. Studies also had to use 'root-form' implants and have a mean follow-up of at least 12 months from implant loading or a follow-up range that exceeded 24 months. Eligible studies were also required to follow-up at least 95% of patients and implant survival rate had to be clearly indicated or calculable from data reported. The main outcome of interest was implant survival rate.

The included studies were randomised controlled trials (RCTs), controlled trials, case series, and retrospective studies, with follow-up duration ranging from 0 to 144 months, using of a number of graft materials (alone or in combination). In the included studies there were also substantial differences in patients' residual crestal bone height, type of implant placed, and success and survival criteria. All of the included studies provided outcomes considering the implant as the unit of analysis. Smooth and rough implant surfaces were investigated.

Studies were selected by two reviewers.

The authors did not state that they assessed validity.

Authors were contacted to clarify information if necessary. It appeared that data were extracted independently by two reviewers.

The studies were combined in a narrative synthesis, grouped according to the type of graft material used (three subgroups: autogenous bone alone; autogenous bone combined with bone substitutes; and bone substitutes alone), implant surface (two subgroups: machined surface and textured surface) and implant placement timing (two subgroups: simultaneous technique and delayed technique). Each subgroup was further subdivided into follow-up duration of less than 36 months or at least 36 months. Percentage survival rates were calculated according to graft material, implant surface and implant placement timing.

Fifty-nine studies were included (n=4,018 patients, range 12 to 731; 13,162 implants). Four studies were RCTs (n=124 patients), 11 were controlled trials (n=1,269 patients), 23 were case series (n=1,195 patients) and 21 were retrospective studies (n=1,430 patients).

Graft material (51 studies): The overall implant survival rate was lower using autogenous bone grafts (88.9%) compared with combined grafts (94.7%) or bone substitutes alone (96.1%).

Implant surface (52 studies): The mean survival rate of implants with a machined surface was 86.3% (950 patients, 3,346 implants placed), compared with 96.7% for implants with a rough surface (2,544 patients, 8,303 implants placed).

Implant placement timing (47 studies): Implant survival rates were similar in the simultaneous technique and delayed technique subgroups, and for follow-up greater or less than 36 weeks.

Bone substitutes were successfully used for sinus augmentation and reduced donor-site morbidity. Long term studies are needed to confirm the performance of non-autogenous grafts. The use of implants with a textured surface may improve the outcome in any graft type.

The review question was supported by inclusion criteria for intervention, outcomes and study design. Several databases were searched for studies in any language, reducing the risk of language bias. No searches for unpublished data were reported, although an unpublished study was included, so it was unclear whether publication bias was likely. Study selection was performed in duplicate, but it was unclear whether a similar method to reduce error and bias was employed during the data extraction. Study quality was not assessed.

The decision to combine the studies in a narrative synthesis appeared appropriate. However, the authors appeared to have simply pooled percentage survival data, without weighting according to primary study, which may have been inappropriate. The authors discussed limitations to the data in terms of low-level study designs and heterogeneity between studies.

The authors' conclusions reflected the data presented, but need to be interpreted with caution due to lack of validity assessment and possible inappropriate pooling of data.

Practice: The authors did not state any implications for practice.

Research: The authors stated that further studies of high methodological quality are needed to assess the individual performance of the different bone substitutes and to evaluate the influence of other variables (e.g. the amount of residual crestal bone in the posterior maxilla, the patients systemic condition and smoking habits) on the survival of implants placed in the grafted maxillary sinus.

Not stated.

Del Fabbro M, Testori T, Francetti L, Weinstein R. Systematic review of survival rates for implants placed in the grafted maxillary sinus. International Journal of Periodontics and Restorative Dentistry 2004;24(6):565-577.

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.