Microleakage and Micrographic Evaluation of Composite Restorations with Various Bases over ZOE Layer in Pulpotomized Primary Molars

Zinc oxide eugenol (ZOE) under composite restorations should becovered with a suitable material in order to prevent the harmful effect of ZOE onthe composite. The aim of this in vitro study was to evaluate microleakage ofcomposite restorations in pulpotomized primary molars with different bases forcovering the ZOE layer and to assess the distance between different layers.Materials and Methods: Proximo-occlusal cavities were prepared in 78 extractedsecond primary molars. Carious lesions were removed and pulpotomy wascarried out. Zinc oxide eugenol paste was placed in 2-mm thickness. The teethwere randomly divided in 6 groups and restored as follows: 1. Light-cured composite;2. Resin-modified glass-ionomer and composite resin; 3. Glass-ionomerand composite resin; 4. Light-cured calcium hydroxide and composite resin; 5.Calcium hydroxide and composite resin; 6. Amalgam and composite resin. Therestored specimens were thermocycled for 500 cycles (5°C/55°C) and microleakagewas assessed by dye penetration technique. Three specimens from eachgroup were processed for scanning electron microscope evaluation to determinethe distance between the layers. The results were analyzed by Kruskal-Wallis andDunn tests.Results: Microleakage assessment revealed significant differences between thegroups (P=0.04), with the amalgam group exhibiting the lowest microleakagevalues. In SEM micrographs no significant differences were observed in the distancebetween ZOE base layers (P=0.94) and base-composite layers (P=0.47);however, the amalgam group had the lowest distances.Conclusion: The use of amalgam over zinc oxide eugenol layer in pulpotomizedprimary molars decreases microleakage.