Efeitos dos meios de armazenamento na composição química da dentina humana

Abstract

The purpose of this study was to evaluate the effect of different tooth storage media for in vitro studies on the chemical composition of dentin. Sixty healthy third molars were selected and divided into 7 groups according to the type of storage (n = 10). Control group: samples prepared and analyzed in less than 24 hours of dental extraction, and were not stored in any medium; Group DI: samples stored in distilled water; Group DE: samples stored in deionized water; Group U: samples stored in ultrapure water; Group S: samples stored in physiological saline; Group AS: samples stored in artificial saliva; Group F: samples frozen at -20º C. The teeth were cut and after 30 days of storage the samples were evaluated using Fourier Transform Infrared Spectroscopy (FTIR), using the following ratios: phosphate / amide I; carbonate / phosphate; and amide I / amide III. Then, the same samples were submitted to atomic composition analysis using X-ray Dispersive Energy Spectroscopy (EDX), which measured the levels of C, Na, Mg, P, Ca and the Ca / P ratio. Data were evaluated using the Analysis of Variance - One-Way ANOVA followed by Dunnett's Multiple Comparison Test (p <0.05). The electrical conductivity and pH of the media were evaluated before and after use as storage. The FTIR showed a difference between the control group and the ultrapure water group (p <0.001) for the phosphate / amide I ratio, as well as for artificial saliva (p = 0.033). For the carbonate / phosphate ratio, there was difference of the control group for the artificial saliva (p = 0.012) and for the deionized water (p = 0.002). For the amide I / amide III ratio, there was a significant difference of the control group for distilled water (p <0.001), saline (p <0.001) and deionized water (p = 0.009). When evaluating the Ca / P ratio, the statistical analysis showed that the samples of deionized water, artificial saliva and ultrapure water were different from the control group (p <0.001). An increase in electrical conductivity was observed for all media after storage of the samples, being more evident in ultrapure water. It was concluded that the storage media can interact with the chemical composition of dentin. The characteristics of the dentin stored in ultrapure water presented the greatest difference in relation to the detina of the control group; while frozen dentin presented the most similar results.