Coloring in teeth
A) Intrinsic coloring 
1) Intrinsic coloration due to systemic factors: coloring due to reasons such as Tetracycline (antibiotic), fluorosis, thalassemia, and porphyry. 2) Intrinsic coloring due to local factors: trauma, dental extract (pulp) necrosis, milk tooth root tip inflammation, decay, coloring due to dental materials
B) External coloring 1) Coloring related to the use of cigarettes, pipe, cigars and tobacco products. 2) Coloring related to coloring beverages such as cola, tea, and coffee. 3) Coloring related to drugs and industrial products. 4) Colorings due to the use of long-term chlorhexidine gargles. 5) Coloring in patients who do not perform the oral hygiene well.
