The site of division of the roots in a multi-rooted tooth (bi- or trifurcation). The furcation area is the area of interradicular bone in the region of the tooth root furcation. A furcation probe is a double-ended hand instrument designed to help determine the extent of interradicular bone loss in the furcation area. Nabers furcation probe see probe. The presence of periodontal destruction in the furcation area reduces the long-term prognosis for tooth survival. Furcation involvement can be classified according to the extent of horizontal bone loss.
Classification of furcation involvement
The furcation opening can be felt upon probing. The horizontal probing depth is less than one third of the bucco-lingual width of the tooth.
The horizontal loss of periodontal support exceeds one third of the width of the tooth, but does not extend to the other side of the furcation area.
The probe passes through the entire dimension of the furcation.