Does the use of bonding agents improve the performance and longevity of dental amalgam restorations?
Data sources: Sources of data were the Cochrane Oral Health Group’s Trials Register, Cochrane CENTRAL (Cochrane Library), Medline and Embase. Reference lists of relevant articles were also searched and the investigators of the included studies were contacted for details of additional published and unpublished trials.
Study selection Randomised controlled trials (RCT) were chosen that compared adhesively bonded versus traditional nonbonded amalgam restorations in conventional preparations utilising deliberate retention, in adults with permanent molar and premolar teeth suitable for Class I and II amalgam restorations only.
Data extraction and synthesis Two review authors independently screened papers, extracted trial details and assessed the risk of bias in the included study.
Results: One trial was included, comprising 31 patients who received 113 restorations. At 2 years, only three out of 53 restorations in the nonbonded group were lost, which was attributed to a lack of retention, and 55 out of 60 bonded restorations survived, with five unaccounted for at followup. Postinsertion sensitivity was not significantly different (P >0.05) at baseline or 2-year followup. No fractures of tooth tissue were reported and there was no significant difference between the groups or matched pairs of restorations in their marginal adaptation (P >0.05).
Conclusions: There is no evidence to either claim or refute a difference in survival between bonded and nonbonded amalgam restorations. This review only found one methodologically sound but somewhat under-reported trial. This trial did not find any significant difference in the in-service performance of moderately sized adhesively bonded amalgam restorations, in terms of their survival rate and marginal integrity, in comparison with nonbonded amalgam restorations over a 2-year period. In view of the lack of evidence on the additional benefit of adhesively bonding amalgam compared with with nonbonded amalgam, it is important that clinicians are mindful of the additional costs that may be incurred.
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