Hi, WC to health care magic.
First of all, in RCT, we usually use a far less caustic agent than the one used for dental bleach (superoxol). Generally it could be
carbamide peroxide gel or EDTA paste for softening dentin. We also use irrigants like saline, hexidine or sodium hypochlorite. The quantity of these substance used during
root canal is minimal and does not have any significant side effect even if ingested accidentally. The immediate response you had after ingestion - cough and breathing difficulty - were, of course, due to ingestion ( immediate response). However, 2 weeks later, you say that you had
acid reflux and throat blockage. This 2 weeks interval suggest that the substance you ingested is not related to you current condition. You have to check with a physician for
chest infection,
gastritis, GERD etc. Avoid spicy food, smoking, alcohol and oily food. Do not wear anything tight around your waist, avoid lying immediately after meals and maintain proper meal schedule. These will help along with physician consult. Get well soon!