Avaliação da citotoxidade do ácido glicólico e sua influência na microdureza da dentina radicular: um estudo in vitro

Abstract

To evaluate, in vitro, the influence of the use of 3 glycolic acid concentrations on the cytotoxicity and microhardness of root dentin. Cytotoxicity was evaluated by counting living and dead cells. For this study, human lymphocytes were cultured from blood donors not exposed to carcinogens. The lymphocytes were released into karyotype media and incubated at 37 ° C for a total time of 72 hours. After 48 hours, the treatments were incubated and divided into treatment groups as described above. In each treatment group, for greater reliability of results, two slides were made. Total cells were counted from each slide, separated into live and dead, and averaged in percentage, followed by ANOVA followed by Tukey post-hoc with a significance level of 5%. Thirty extracted human uniricular teeth were used for the microhardness test. The coronary portion was sectioned at the cementoenamel junction and two longitudinal grooves were made at the buccal and lingual surfaces using a diamond disc. The roots were cleaved into two halves with the aid of a microtome slide, providing two samples of each root. They were fixed in self-curing acrylic resin, leaving the root canal dentin exposed. The 60 samples were sanded, polished and randomly divided into three groups (n = 10), according to the final irrigant used, as follows: G1 - distilled water; G2 - EDTA 17%; G3 - QMix; G4 - 10% glycolic acid; G5 - Glycolic acid 17%; G4 - 25% glycolic acid. The samples were irrigated with 5 ml of the final irrigants tested, remaining in contact for a period of 1 minute. The microhardness of the root dentin was performed by a Vickers microdurometer, performing 3 indentations before and after the treatments. All final irrigants were cytotoxic when compared to the control group, 10% glycolic acid presented lower cytotoxicity than the other used irrigators. All final irrigants tested maintained the same level of microhardness in the root dentin when compared to the control group. Statistical difference between them (p <0.05), all final irrigants were cytotoxic when compared to the control group, glycolic acid 10% presented lower cytotoxicity than the other irrigants used. It was concluded that the tested irrigating solutions were able to induce cell death and did not modify the root hardness microhardness.