Fibre-reinforced resin-bonded FPD have some perceived advantages in terms of aesthetics (because they avoid the use of metal) and can be more conservative to tooth tissue. This systematic review attempts to obtain survival rates of fibre-reinforced resin-bonded FPD and to explore relationships between reported survival rates and risk factors.

The data here were obtained following a Medline search and a search made by hand of reference lists of the selected papers. The number of studies identified was perhaps limited by not using other search engines, by only including papers published in English, and not contacting experts. Fifteen studies were identified and all but one were observational studies (the majority of which were prospective studies). The remaining study was a RCT that compared full ceramic FPD with fibre-reinforced resin-bonded FPD. Including these types of study is reasonable when attempting to ascertain survival rates, but is clearly of limited use when comparing results with other types of bridge.

Little was written about the assessment of the quality of the included studies. Although two independent readers selected the papers, there does not appear to have been an attempt to score or assess the quality of the studies. This may reflect the limited number of studies and sample size. The authors do acknowledge that the limited descriptions of sample and study characteristics restrict the level of evidence.

The missing study details also restrict the conclusions we can draw from the paper. As the authors point out, many of the studies do not describe the patient selection criteria or the failures in relation to basic factors such as retention type or location . Without these details, we are prevented from gaining information that could influence our clinical practice, such as whether anterior or posterior fibre-reinforced resin-bonded FPD perform better. Although it does appear to be the opinion of several of the authors that a posterior location or long span are risk factors (and this may be reasonable), the evidence is not available from this review to support this.

By grouping different types of retainer (inlay, surface and crown), again, it is difficult to draw conclusions from the survival data. If we assume that a full-coverage crown retainer performs differently from a surface retainer, the final survival rate may have little relation to clinical practice. Other factors such as variations in patient selection, choice of materials, luting cements and operator's experience may have a similar effect.

Some of the studies have different criteria for failure, also limiting the validity of the survival data. With some studies not regarding certain technical problems as failures, the survival data may be an overestimate. Few data seem to be available on potential advantages of fibre-reinforced resin-bonded FPD, such as conservative tooth preparation and patient satisfaction. Again, without this information it is difficult to apply the findings of the review to clinical practice.

Many of these problems are identified by the authors. The conclusions and methods here are reasonable when considering the limited number of studies and the information available from the studies that have been done in this area. Clearly, further high quality and well designed trials are required before we have sufficient evidence to warrant changing clinical practice.