Dental The prognosis of bleaching of a discoloured tooth is good in all the given conditions except: A Discolouration due to products of pulp decomposition. B Discolouration due to food debris. C Discolouration due to metallic salts. D Discolouration due to chromogenic bacteria. 💡 Explanation The prognosis of bleaching of a discoloured tooth is good in all the given conditions except: ✓ Correct Answer: C. Discolouration due to metallic salts.