Gingival discolouration
A. Bismuth in blood - Blue-black colour
B. Mercury in blood - black
C. Lead in blood – red / reddish blue.

1. PAIN
   ● Within 48 hours
   ➔ Deep cavity ー patients come with sensitivity to hot and cold food.
   ➔ Pulp exposed.
   ➔ Class 2 cases ー pulpal horns exposure.
   ● Supra occlusion / High point / Defective Occlusion
   ➔ Within 1 week.
   ➔ TOP +ve
   ➔ Sensitivity to hot and cold food ーdue to detachment of CEJ from gums ー thus exposing
   dentin ∴ Sensitivity.
   ● If only sensitivity
   ➔ Dentine cause and not high point