The tooth root is a part of the tooth and serves to attach it to the periodontium. The front teeth usually have one root, while the more distal teeth have up to three roots. Inflammation in the root of the tooth or at the tip of the root is often very painful and, without treatment, can lead to the destruction of the tooth.
What is the root of the tooth?
The root of the tooth is that part of the tooth which lies below the crown and neck of the tooth and anchors it in the tooth socket. The tooth root is encased in a layer of tooth cementum. The tooth cementum is composed of minerals, collagen fibers and water and serves to protect the root. It is formed by cementoblasts, which are a special form of connective tissue cells. The tooth root usually tapers towards the root tip and is therefore conical. Furthermore, the tooth root is twice as long as the tooth crown. Incisors and canines usually have one root, premolars (small molars) have two roots and molars have two to three roots. Even the first teeth (milk teeth) have roots when they are fully grown.
Anatomy and structure
The roots of the teeth consist mostly of the dentin (tooth bone). On the surface, the dentin is covered with dental cementum. The dentin has a bone-like structure and is composed of 70 percent calcium hydroxyapatite, 20 percent organic material (mainly collagen) and 10 percent water. It surrounds the dental pulp. The tooth cementum located on the surface of the dentin is also made up of 65 percent minerals such as hydroxyapatite, 23 percent collagen fibers and 12 percent water. Thus, the basic substance of dental cement resembles that of the dentine. However, its structure is somewhat different. It occurs in four modifications. However, like dentin, it is also formed from cementoblasts. The tip of the tooth root is located in the tooth socket and has an access opening for nerve fibers and blood vessels that supply the entire tooth. The entirety of blood vessels and nerve fibers is also known as dental pulp, whose narrow extensions into the tooth root are also known as root canals. Human teeth have a varying number of roots. The more distal (backward) the teeth are, the more roots they have. However, there are exceptions. For example, the first upper premolar has two roots, while the second upper premolar again has only one root. There are also numerous anomalies in the number and shape of roots. Among others, fused roots or single-rooted teeth with two root tips are found. The upper molars usually have three roots. One very strong root (the palatal root) is located towards the palatal side. The two smaller vestibular roots are located on the cheek side. Wisdom teeth are often found to have very large deviations with up to ten atrophied root canals. In this case, their roots may also have barbs, so tooth extractions are often very challenging and root canals are not possible at all.
Function and tasks
The function of the tooth root is to anchor the tooth in the periodontium and to supply it via root canals. The periodontium includes the tooth compartment of the jaw, the gums, the periodontium and the root cementum. The part of the jaw bone in which the tooth socket is located is called the alveolar process (processus alveolaris). The gum is part of the oral mucosa. It covers the tooth socket and encloses the teeth cervically as an epithelial cuff (marginal epithelium). The root membrane represents the connective tissue of the periodontium. It consists of connective tissue fibers that bridge the short distance between the tooth cementum and the wall of the tooth socket. The tooth is thus anchored somewhat movably by a wedge in the tooth socket. This wedging, stabilized by connective tissue fibers, is also called gomphosis. Thus, the gomphosis belongs to the connective tissue-like bone connections. In addition to its anchoring function, the tooth root also provides a supply to the tooth via the root tip. Both blood vessels and nerve fibers have access to the tooth through the root canals.
Diseases
The best-known disease of the tooth root is pulpitis. Pulpitis characterizes an inflammation in the root of the tooth. This is usually an infection with caries bacteria. Caries bacteria are composed of different types of streptococci.Initially, bacteria cultures develop on the tooth due to unremoved food residues (especially carbohydrates), which produce acids. The acids dissolve the enamel on the tooth crown. Holes are formed, which are further colonized by bacteria (caries). If left untreated, the process continues until the bacteria also invade the root of the tooth. The gums can also be attacked by the bacteria (periodontitis), creating large pockets in the gums, which in turn become permeable to further bacteria and penetrate to the root of the tooth. In both cases, inflammation of the tooth root (pulpitis) can occur, which is very painful. In pulpitis, the dental pulp (tooth pulp) becomes inflamed, as the name suggests. However, the dental pulp consists of nerve fibers and blood vessels. As a result, nerve fibers become directly inflamed. This direct involvement of the nerves causes extremely severe pain. Toothache is therefore one of the most unbearable pains of all. In this case, the dentist must perform root canal treatment by drilling out the tooth, removing inflamed tissue and flushing out the root canal with antibacterial solution. The root canals are then sealed with a root filling paste.
