Effect of Storage Time and Temperature on Salivary Total Antioxidant Capacity, Total Oxidant Status, and Oxidant Stress Index

Objective: The aim of this study was to compare the effects of short-term storage in two different temperatures on stability of salivary total antioxidant capacity (TAC), total oxidant status (TOS) and oxidant stress index (OSI). Material and methods: Saliva samples were collected from twenty healthy volunteers for the study. An aliquot was selected for immediate analysis and the rest was stored at -20 degrees C and -80 degrees C for a period of 120 days, and analyzes were performed at 15, 30, 45, 60, 90 and 120 days. The determination of the TOS and the TAC were performed by colorimetric methods. Results: The results show that the two storage temperatures were able to preserve oxidants and antioxidants up to 60 days with similar levels when compared with fresh samples. When comparing the different storage temperatures at each time point, no significant differences were observed. Finally, the OSI remains constant over time of storage at both temperatures without statistically significant differences between them. The results were expressed as mean +/- standard error of mean. Statistical analysis was performed using the repeated-measures analysis of variance (ANOVA), the Bonferroni and t-test. A p-value <0.05 was accepted to be statistically significant. Conclusion: The two temperatures were able to keep salivary TOS and TAC levels similar to fresh saliva samples. Therefore they are reliable for assessing oxidative stress up to 60 days.