Systematic review on highly viscous glass-ionomer cement/resin coating restorations (Part II): Do they merge Minamata Convention and minimum intervention dentistry?

Background: With the Minamata Convention the use of mercury will be phased down, and this undoubtedly will have an effect on dental treatment regimens and economic resources. Composite resin restorations are considered viable alternatives to amalgam fillings; however, these will not be covered completely by health insurance systems in many countries. Recently, a high-viscosity glass-ionomer cement (hvGIC) processed with a resinous coating (RC) has been introduced, and has been marketed as a restorative material in load-bearing Class I cavities (and in Class II cavities with limited size), thus serving as a possible alternative to amalgam fillings. Objective: To discuss the outcome based on the evaluation presented in Part I of this paper, and to critically appraise the methodologies of the various studies. Results: Two of the included studies were industry-funded, and status of the other clinical trials remained unclear. Quality of study reporting was considered perfectible. The use of a light-cured nanofilled resin coating material would seem advantageous, at least when regarding short- and medium term outcomes. Conclusion: Within the respective indications and cavity geometries, the hvGIC/RC approach would seem promising, could merge the phase-down of mercury and the objectives of minimally invasive treatment to some extent, and might be a restorative alternative for patients suffering from allergies or not willing to afford other sophisticated or expensive techniques. These recommendations are based on studies evaluating EQUIA Fil (GC), but are not transferable to clinical perspectives of the glass hybrid successor product (EQUIA Forte; GC). Keywords: amalgam, Class I and Class II cavities, clinical trial, composite resin, high-viscosity glass-ionomer cement, Minamata Convention, minimum intervention dentistry, resin coating