Prevention of Bacterial Infiltration in Class 1 Temporary Restorations Using Zinc Oxide/Calcium Sulphate Filling Materials: An In Vitro Study

This study evaluated sealing properties of zinc oxide/calcium sulphate filling material (Plastor (c)) to prevent bacterial infiltration in simulated Class 1 cavities with and without the presence of a spacer apically the restoration. Twenty-eight experimental Eppendorf tubes containing Tryptic Soy Agar were prepared and divided into seven groups: group A (Plastor (c)), group B (Plastor (c) + cotton pellet), group C (Plastor (c) + cotton pellet soaked of m-cresyl acetate), group D (Plastor (c) + cotton pellet soaked of eugenol), group E (Plastor (c) + PTFE pellet), group F (positive control), and group G (negative control). All prepared vials were individually immersed in tubes containing 5 mL of a suspension of Streptococcus mutans (10(5) CFU/mL) previously prepared and then incubated at 37 degrees C for 5 and 10 days. Subsequently, agar was collected and tested for S.mutans using real-time PCR. Aliquots of each agar samples were separately seeded on TSA for S. mutans isolation. The real-time PCR tests were negative for S. mutans on all the vials at both T5 and T10, except for positive control resulted positive at both T5 and T10. The isolation tests showed bacterial growth of S. mutans only with the agar samples collected from the vials of positive control, confirming real-time PCR tests. This in vitro study evidenced complete sealing ability of zinc oxide/calcium sulphate in temporary restorations of Class 1 cavities without mechanical loading at 10 days and complete immersion in a bacterial suspension. Moreover, sealing ability is not influenced by presence of spacers.