Dental anatomy. A study of transplantation of teeth requires first learning about the morphology of the teeth. The dental anatomy is already extensively described in several books [1, 2], therefore only a short description will be given here. Humans have two sets of teeth, 20 primary teeth which will be eventually replaced by 32 permanent teeth. The teeth are equally divided between the upper (maxilla) and lower jaw (mandible). There are four different types of teeth: incisors, canines, premolars and molars. Each tooth consists of a crown and a root (Figure 1 left). The crown is visible in the mouth and covered with enamel, while the root is buried in the alveolar bone and covered with cementum. The tooth is mainly composed of dentin, a calcified tissue surrounding the pulp cavity of a tooth. The pulp cavity consists of pulp tissue and can be divided into two compartments, the pulp chamber in the crown portion and the pulp canal in the root portion. Anterior teeth (incisors and canines) usually have one root canal, whereas posterior teeth (premolars and molars) have multiple canals. The pulp tissue contains blood vessels, nerves and cellular connective tissue. The nerves and blood vessels enter and leave the tooth through the apical foramen, an opening at the apex of the root [1, 2]. The crowns of the teeth have different surfaces which are named according to their positions (Figure 1 right). In the incisors and canines, the surfaces facing the lips are called labial surfaces. The surfaces toward the cheek in premolars and molars are called buccal surfaces. Labial and buccal surfaces are collectively termed facial surfaces. All surfaces related to the tongue are called lingual surfaces. Furthermore, each tooth has two proximal surfaces, one that is orientated toward the midline of the dental arch (mesial surface) and another faced away from the midline (distal surface). Finally, the cutting edge of an anterior tooth is called incisal surface while the chewing plane of a posterior tooth is termed occlusal surface [1, 2]. Figure 1: A schematic picture of a normal tooth is shown at the left. A schematic picture of the tooth surfaces, named according to their positions, is shown at the right.
