Glass-ionomer restoratives: a systematic review of a secondary caries treatment effect

It is generally accepted that glass ionomers inhibit secondary caries in vivo, and data from in vitro studies support this effect. The aim of this review was a systematic assessment, from the literature, of clinical evidence for the ability of glass-ionomer restoratives to inhibit secondary caries at the restoration margin. Inclusion and exclusion criteria for selection of the review papers were established prior to commencement of the literature search. Papers which conformed to these criteria, and reported on secondary caries as an outcome, were selected (N = 52). Primary and secondary lists of systematic criteria for use in the assessment of the papers were drawn up. The primary list of 14 criteria was applied to each paper. No paper fulfilled all these criteria, necessitating the use of the secondary measures: (i) a prospective study and (ii) use of an appropriate control. This yielded 28 papers. Tabulation of these papers by occurrence of secondary caries in the glass-ionomer or control groups demonstrated an even distribution between positive and negative outcomes. Valid evidence is considered to be best obtained from randomized, controlled studies of sufficient sample size. No conclusive evidence for or against a treatment effect of inhibition of secondary caries by the glass-ionomer restoratives was obtained from the systematic review. There is a need for appraisal of the methods currently adopted for the clinical evaluation of glass-ionomer restorative materials, and for further development of the methodology to support future systematic reviews.