Hi.. Welcome to Thanks for the query.. I have gone through your query and can understand your concerns.. First of all I would like to tell you that if you have to go for dental checkup only and no dental procedure is to be carried out then there is no need for taking antibiotics as only checkup does not need antibiotic that too such a high dose of 4 capsules.. As of now it seems that you are suffering from antibiotic induced Gastritis as Clindamycin is an antibiotic and at times intake of antibiotics can cause Hyperacidity as well as digestive disturbances.. This happens because the antibiotics irritates the linig of oesophagus and stomach and also cause increased acid formation in stomach leading to heartburn.. It is however temporary and resolves as the antibiotic intake is stopped.. You can consult your treating physician if the symptoms are severe.. As of now, till you are on medication you should take empty stomach Pantoprazole or Omeprazole.. Take antacids like Milk of magnesia half an hour before meals.. Drink plenty of water Take more of yoghurt in diet.. Never take antibiotics on an empty stomach.. Take small frequent meals and avoid spicy foods and also avoid large heavy meals.. Hope this information helps..