Return to Article Details Retraction: Singhal R, Rai B. sTNF-R Levels: Apical Periodontitis Linked to Coronary Heart Disease. Open Access Maced J Med Sci. 2017; 5(1):68-1 and Rai B, Kaur J, Jain R. Salivary and serum 8-hydroxydeoxyguanosine level in simulated microgravity. Maced J Download Download PDF