Background: The ideal root canal filling for endodontic treatment of primary teeth with necrotic pulp must have antimicrobial activity, not cause tooth discoloration or interfere with the eruption of permanent successor teeth. This study aimed to evaluate physiochemical properties of a novel paste (CZ Paste) for endodontic treatment of primary teeth with necrotic pulp and compare its antimicrobial activity to Chloramphenicol, Tetracycline, Zinc oxide (CTZ) and Zinc Oxide eugenol (ZOE) pastes. Methods: CZ, CTZ and ZOE pastes were homogenized with eugenol at the time of testing. Fourier Transform Infrared spectroscopy (FTIR) and Differential Scanning Calorimetry (DSC) tests were performed. Antimicrobial activity was assessed using agar diffusion test (ADT), direct contact test (DCT) and bactericidal effect assessment against Staphylococcus aureus, Enterococcus faecalis and Pseudomonas aeruginosa. Results: FTIR showed that CZ paste has a similar profile to chloramphenicol spectrum and in DSC thermograms it demonstrated a slight change in endothermic transition temperature. In the ADT, CTZ paste and CZ paste presented similar inhibition zone diameters and were higher than ZOE paste (P < 0.05). All pastes inhibited the growth of tested micro-organisms in DCT. Bactericidal assessment test showed that only CZ and CTZ pastes had bactericidal effect. Conclusion: CZ paste could be an alternative for endodontic treatment of primary teeth with necrotic pulp.
Key words: Primary tooth, Pulpectomy, Root canal filling materials, Antibiotic paste, Bacteria.