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Chen J, Cai H et al. J Dent 2017;59: 2–10

But despite this, the investigators state that inlay-retained fixed dental prostheses can still be used in the short- and middle-term as an alternative to short-span conventional fixed dental prostheses and implant-supported single crowns.

It may seem curious to mention in this paper the Rochette bridge, with its arcane perforations in the framework to retain the lugs of chemically-cured resin composite. However, the Rochette bridge was the starting point for contemporary minimal invasive bridges. Has the inclusion of inlays incorporated in the framework been a major advance? A cursory survey of the literature gives no steer, as the survival of such bridges seem to vary from a mere 38% to as high as 95.8%. But where does all this leave the practitioner?

Following exclusions, the final review comprised eleven studies, ten of which were prospective cohort studies and one RCT. The Newcastle-Ottawa scale was used to grade the quality of the cohort studies. The mean score was 4.0, with a score less than 6 regarded as of low quality. In addition, two studies were carried out with the same cohort of patients; of concern, markedly dissimilar results were reported albeit over different observation periods. With respect to the RCT, it was judged there 'might also have a high risk of bias' with few details on avoidance of selection bias and blinding. Then there was an almost bewildering heterogenicity as to the provision of the inlay-retained fixed dental prosthesis. For example, some inlay retainers were of a conservative tub-shaped design, whereas others were of extensive design incorporating an interdental box. Some frameworks used short retainer wings. Then several different materials have been used to form the framework with associated distinct surface treatments. In addition, different brands of luting cements have been used.

The key outcome measure was survival/'failure rate': 61 of the 394 inlay-retained fixed dental prostheses 'debonded, totally lost or required refabrication' over a mean observational period of 3.8 years. Using Poisson regression analysis, interestingly there was no difference between bridges with frameworks constructed from ceramic/metal and 'fiber-reinforced composite'. Of note, however, most of the studies examining the failure of fibre-reinforced composite bridges had a short follow-up time of 2–3 years. Zirconia-based bridges appeared to have superior outcomes to glass ceramic bridges.

The most frequent failure for metal or ceramic bridges was debonding, and fracture for fibre-reinforced composite bridges. The most commom 'biological' reasons for failure were secondary caries and sensitivity. Tooth sensitivity tended to regress soon after cementation.