Fluid flow in or out of the dentinal tubules is proportional to the tubule diameter by
fluid flow in dentin tubules follows Poiseuille’s law as all tubular structures:
Q=Pr4/8nl
Q= blood flow
P= pressure difference
N= velocity
R= radius of vessel
L= length of vessel
Third power of the diameter
Sixth power of the diameter
Square of diameter
Fourth power of diameter