Evaluation of the Genotoxicity of Endodontic Materials for Deciduous Teeth Using the Comet Assay

Abstract

Objective: To evaluate genotoxicity of zinc oxide, P. A. calcium hydroxide, mineral trioxide aggregate and an iodoform paste using comet assay on human lymphocytes. Material and Methods: Two positive controls were used: methyl-methanesulfonate for the P.A. calcium hydroxide and mineral trioxide aggregate; and doxorubicin for the iodoform paste and zinc oxide. There were also two negative controls: distilled water for the P.A. calcium hydroxide and mineral trioxide aggregate; and DMSO for the iodoform paste and zinc oxide. Comets were identified using fluorescence microscopy and 100 of them were counted on each of the three slides analyzed per drug test. A damage index was established, taking into consideration the score pattern that had previously been determined from the size and intensity of the comet tail. Analysis of variance, followed by Tukey's test, was used to compare the means of the DNA damage indices. Results: The DNA damage index observed for mineral trioxide aggregate (7.08 to 8.58) and P.A. calcium hydroxide (6.50 to 8.33), which were similar to negative control index. On the other hand, damage index for zinc oxide (104.7 to 218.50) and iodoform paste (115.7 to 210.7) were similar to positive control index. Conclusion: Iodoform paste and zinc oxide showed genotoxicity at all concentrations used.

Investigation of Spark Plasma Sintering on Microstructure-Properties of Zirconia Reinforced Fluormica Glass for Dental Restorations

“…The Comet assay typically detects DNA damage of cells through the tailing of the comet through the technique of electrophoresis [ 65 , 66 , 67 , 68 , 69 ]. The Comet assay evaluates the genotoxicity of dental composites, bleaching agents, dental ceramics, polymethyl methacrylate resins, pulp capping, and dentin bonding agents [ 70 , 71 ]. The International Workshop on Genotoxicity Test Procedures recommends visual scoring of cells based on the tail length and classifies them into five classes: class 0, undamaged cells having no tail; class 1, cells having a tail shorter than the diameter of the head (nucleus); class 2, cells having a tail length 1–2 times the diameter of the head; class 3, cells having a tail longer than two times the diameter of the head; and class 4, comets having no heads [ 71 ].…”