The pulp becomes necrotic because of tooth trauma or tooth decay, and the tooth will appear greyish-black. Endodontic treatment must be done to treat the discoloured tooth which has pulp necrosis. If teeth still appear greyish-black, dentist can treat the discolored teeth by bleaching , laminate veneer or crown .
Reasoning, as a way of proving arguments, comes in many different forms. Different forms of reasoning are accepted in different fields and contexts. Arguing with family members generally relies on different methods of reasoning than arguing with professors.
In logic you can always absolutely prove what you set out to prove if you do it right, but its utility is limited in day-to-day life. Reasoning is much broader and assembles evidence to support a viewpoint, but it seldom constitutes absolute proof.