In dentistry

Dentistry

Dentistry is the branch of medicine that is involved in the study, diagnosis, prevention, and treatment of diseases, disorders and conditions of the oral cavity, maxillofacial area and the adjacent and associated structures and their impact on the human body. Dentistry is widely considered...

, a furcation defect is a term used to describe bone loss, usually a result of periodontal disease

Periodontal disease

Periodontitis is a set of inflammatory diseases affecting the periodontium, i.e., the tissues that surround and support the teeth. Periodontitis involves progressive loss of the alveolar bone around the teeth, and if left untreated, can lead to the loosening and subsequent loss of teeth...

, affecting the base of the root trunk of a tooth where two or more roots meet. The extent and configuration of the defect are factors in both diagnosis and treatment planning.

A tooth with a furcation defect has typically reduced prognosis owing to the difficulty of rendering the furcation area free from periodontal pathogens. For this reason surgical periodontal treatment may be considered to allow vision and access to the furcation.

Because of its importance in the assessment of periodontal disease, a number of methods of classification have evolved to measure and record the severity of furcation involvement; most of the indices are based on horizontal measurements of attachment loss in the furcation.

In 1953, Irving Glickman

Irving Glickman

Irving Glickman was a clinical researcher in the field of periodontology. He was one of the first to classify furcation defects and the role of occlusal trauma on periodontal disease.-References:...

graded furcation involvement into the following four classes:

• Grade I - Incipient furcation involvement, with any associated pocketing remaining coronal
  Commonly used terms of relationship and comparison in dentistry
  There are numerous commonly used terms of relationship and comparison that refer to different aspects of teeth and are frequently utilized in articles about dentistry...
  
   to the alveolar bone; primarily affects the soft tissue
  Gingiva
  The gingiva , or gums, consists of the mucosal tissue that lies over the mandible and maxilla inside the mouth.-General description:...
  
  . Early bone loss may have occurred but is rarely evident radiographically
  Dental radiography
  Dental radiographs, commonly referred to as X-ray films, or informally, X-rays, are pictures of the teeth, bones, and surrounding soft tissues to screen for and help identify problems with the teeth, mouth, and jaw. X-ray pictures can show cavities, cancerous or benign masses, hidden dental...
  
  .
• Grade II - There is a definite horizontal component to the bone loss between roots resulting in a probeable
  Periodontal probe
  A periodontal probe is an instrument in dentistry commonly used in the dental armamentarium. It is usually long, thin, and blunted at the end. The primary purpose of a periodontal probe is to measure pocket depths around a tooth in order to establish the state of health of the periodontium...
  
   area, but bone remains attached to the tooth so that multiple areas of furcal bone loss, if present, do not communicate.
• Grade III - Bone is no longer attached to the furcation of the tooth, essentially resulting in a through-and-through tunnel. Because of an angle in this tunnel, however, the furcation may not be able to be probed in its entirety; if cumulative measurements from different sides equal or exceed the width of the tooth, however, a grade III defect may be assumed. In early grade III lesions, soft tissue may still occlude the furcation involvement, though, making it difficult to detect.
• Grade IV - Essentially a super grade III lesion, grade IV describes a through-and-through lesion that has sustained enough bone loss to make it completely probeable.

In 2000, Fedi, et al. modified Glickman's classification to include two degrees of a grade II furcation defect:

• Grade II degree I - exists when furcal bone loss possesses a vertical component of >1 but <3mm
  Millimetre
  The millimetre is a unit of length in the metric system, equal to one thousandth of a metre, which is the SI base unit of length....
  
  .
• Grade II degree II - exists when furcal bone loss possesses a vertical component of >3mm, but still does not communicate through-and-through.

In 1975, Sven-Erik Hamp, together with Lindhe

Jan Lindhe

Jan Lindhe is a Swedish periodontist and a world-renowned clinical research scientist specializing in periodontology.-Biography:Lindhe graduated from the Royal School of Dentistry in Malmö, Sweden. He completed specialty training in oral surgery and periodontology at the University of Lund...

 and Sture Nyman, classified furcation defects by their probeable

Periodontal probe

A periodontal probe is an instrument in dentistry commonly used in the dental armamentarium. It is usually long, thin, and blunted at the end. The primary purpose of a periodontal probe is to measure pocket depths around a tooth in order to establish the state of health of the periodontium...

 depth.

• Class I - Furcation defect is less than 3 mm is depth.
• Class II - Furcation defect is at least 3 mm in depth (and thus, in general, surpassing half of the buccolingual
  Commonly used terms of relationship and comparison in dentistry
  There are numerous commonly used terms of relationship and comparison that refer to different aspects of teeth and are frequently utilized in articles about dentistry...
  
   thickness of the tooth) but not through-and-through (i.e. there is still some interradicular bone attached to the angle of the furcation. The furcation defect is thus a cul-de-sac
  Cul-de-sac
  A cul-de-sac is a word of French origin referring to a dead end, close, no through road or court meaning dead-end street with only one inlet/outlet...
  
  .
• Class III - Furcation defect encompassing the entire width of the tooth so that no bone is attached to the angle of the furcation.