Taurodontism

Taurodontism is a condition found in the molar teeth of humans whereby the body of the tooth and pulp chamber is enlarged vertically at the expense of the roots. As a result, the floor of the pulp and the furcation of the tooth is moved apically down the root. The underlying mechanism of taurodontism is the failure or late invagination of Hertwig's epithelial root sheath, which is responsible for root formation and shaping causing an apical shift of the root furcation.

The constriction at the amelocemental junction is usually reduced or absent. Taurodontism is most commonly found in permanent dentition although the term is traditionally applied to molar teeth. In some cases taurodontism seems to follow an autosomal dominant type of inheritance.

Taurodontism is found in association with amelogenesis imperfecta, ectodermal dysplasia and tricho-dento-osseous syndrome. The term means "bull like" teeth derived from similarity of these teeth to those of ungulate or cud-chewing animals.

According to Mangion taurodontism may be:

• A retrograde character
• A primitive pattern
• Mendelian recessive character
• Atavistic feature
• A mutation

It has also been reported in Klinefelter syndrome, XXYY and Down syndrome . The teeth involved are invariably molars, sometimes single and at the other times multiple teeth may be involved. The teeth themselves may look normal and do not have any particular anatomical character on clinical examination.

On a dental radiograph, the involved tooth looks rectangular in shape without apical taper. The pulp chamber is extremely large and the furcations may be only a few millimeters long at times.

Classification

Taurodontism Shaw

The term taurodontism was coined by Sir Arthur Keith. C.J.Shaw further classified taurodontism into four distinct categories: Cynodont(Normal,) Hypotaurodont, Hypertaurodont and Mesotaurodont.

Shiffman and Chanannel

Later, Shifman & Chanannel created a mathematical criteria based on the physiology of the tooth.

Here a tooth is tarodont if AB/AC >= 0.2 and BD > 2.5mm (A: Lowest point of the roof of the pulp chamber. B: Highest point of the floor of the pulp chamber C: Root Apex D: Cementoenamel junction (CEJ))

Normal: < 20%

Hypo-T: 20–20.9%

Meso-T: 30–39.9%

Hyper-T: 40–75%

Anthropology

Taurodontism is still a condition of anthropological importance as it was seen in Neanderthals.

The trait "is common among extant New World monkeys, apes, and fossil hominins".