structure anatomic of canine and premolar

the structure anatomic( root anatomy )
of canine and Bifurcated root premolar.

FURCATION INVOLVEMENT

A furcation is the branching point
 between roots on a multirooted tooth. 
In the absence of disease, furcations
cannot be clinically probed because
 they are filled in with bone and 
periodontal attachment. With advancing
 periodontal disease, however, attachment
 loss and bone loss may reach a furcation 
area resulting in a furcation involvement.28,29 
Pockets that extend into the furcation create
 areas with difficult access for the dentist