![]() ![]() Within each class, teeth may be classified into different traits. Premolars are found only in permanent teeth there are no premolars in deciduous teeth. There are four classes of teeth: incisors, canines, premolars, and molars. The term, "maxillary", is given to teeth in the upper jaw and "mandibular" to those in the lower jaw. Further, the name depends upon which arch the tooth is found in. Succedaneous would refer to these teeth as a group. ![]() "Succedaneous" refers to those teeth of the permanent dentition that replace primary teeth (incisors, canines, and premolars of the permanent dentition). Often, "deciduous" may be used in place of "primary", and "adult" may be used for "permanent". Teeth can belong to one of two sets of teeth: primary ("baby") teeth or permanent teeth. Teeth are named by their sets and also arch, class, type, and side. This determination is further complicated by the varying appearance of different histologic sections of the same developing tooth, which can appear to be different stages. The staging of tooth development is an attempt to categorize changes that take place along a continuum frequently it is difficult to decide what stage should be assigned to a particular developing tooth. Tooth development is commonly divided into the following stages: the bud stage, the cap, the bell, and finally maturation. Fibroblasts develop the periodontal ligaments which connect teeth to the alveolar bone through cementum. Osteoblasts give rise to the alveolar bone around the roots of teeth. Cementoblasts form the cementum of a tooth. The dental follicle gives rise to three important entities: cementoblasts, osteoblasts, and fibroblasts. Additionally, the junction between the dental papilla and inner enamel epithelium determines the crown shape of a tooth. The dental papilla contains cells that develop into odontoblasts, which are dentin-forming cells. The growth of cervical loop cells into the deeper tissues forms Hertwig's Epithelial Root Sheath, which determines the root shape of the tooth. These cells give rise to ameloblasts, which produce enamel and the reduced enamel epithelium. The enamel organ is composed of the outer enamel epithelium, inner enamel epithelium, stellate reticulum and stratum intermedium. The tooth bud (sometimes called the tooth germ) is an aggregation of cells that eventually forms a tooth and is organized into three parts: the enamel organ, the dental papilla and the dental follicle. It is widely accepted that there is a factor within the tissues of the first branchial arch that is necessary for the development of teeth. If teeth do not start to develop at or near these times, they will not develop at all.Ī significant amount of research has focused on determining the processes that initiate tooth development. Primary (baby) teeth start to form between the sixth and eighth weeks in utero, and permanent teeth begin to form in the twentieth week in utero. For human teeth to have a healthy oral environment, enamel, dentin, cementum, and the periodontium must all develop during appropriate stages of fetal development. Although many diverse species have teeth, non-human tooth development is largely the same as in humans. Tooth development is the complex process by which teeth form from embryonic cells, grow, and erupt into the mouth. Dental work performed mostly in UK/Europe in last half of 20th Century Panoramic x-ray radiography of the teeth of a 64-year-old male. Main article: Human tooth development Radiograph of lower right (from left to right) third, second, and first molars in different stages of development.
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