One of the most important and at present unsolved problems in clinical peri
odontology is the predictable successful treatment of periodontitis-affecte
d furcations of multirooted teeth. Since several therapeutic approaches are
proposed, i.e., conservative, resective or regenerative, a proper diagnosi
s of these lesions is demanding. The aim of the present article is to revie
w the current information on the impact of a proper diagnosis of a furcatio
nal lesion as well as tooth morphology on decision making with regard to di
fferent treatment modalities and to emphasize the need for a detailed clini
cal, radiographical and intraoperative diagnosis of the furcation lesion be
yond the usually performed diagnosis of the degree of furcation involvement
.