Effect of delayed polishing periods on interfacial gap formation of Class V restorations

This in vitro study evaluated the effect of the initial polishing period through 30 minutes, 3 hours, 12 hours, 24 hours and 1 week after setting on the gap formation around Class V restorations. Three resin-modified glass ionomers, one compomer, one conventional glass ionomer and one micro-filled composite were used as controls. When specimens of the two types of glass ionomers and a microfilled composite were polished immediately after the setting procedure, this study showed 100-140 gaps around the X-section of the restorations. In contrast, only 10-40 gaps around the Class V restoration were observed when the specimens were polished after 12 hours of storage. Significant differences were observed between polishing immediately and polishing after 12 hours of storage in the two glass ionomer restorative materials. The compomer did not show this pattern. No significant differences were observed among the six polishing periods of the sum number of gaps at the cavity-restoration interfaces. The tendency of Silux Plus was similar to the two types of glass ionomer materials; namely, when the specimen was polished and inspected after storage in water for 24 hours or one week, the authors observed almost 30 gaps around the restorative cavities.