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In dicot root, the vascular cambium is completely secondary in origin, and it originates from a portion of pericycle tissue. [citation needed] The pericycle regulates the formation of lateral roots by rapidly dividing near the xylem elements of the root. [2] It has been known to often be confused with other parts of the plant.
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. [2] 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. [3]
Tooth development begins at week 6 in utero, in the oral epithelium. The process is divided into three stages: Initiation; Morphogenesis and; Histogenesis [2]; At the end of week 7 i.u., localised proliferations of cells in the dental laminae form round and oval swellings known as tooth buds, which will eventually develop into mesenchymal cells and surround the enamel organ.
The Hertwig epithelial root sheath (HERS) or epithelial root sheath is a proliferation of epithelial cells located at the cervical loop of the enamel organ in a developing tooth. Hertwig epithelial root sheath initiates the formation of dentin in the root of a tooth by causing the differentiation of odontoblasts from the dental papilla .
Cementum is a specialized bone like substance covering the root of a tooth. [15] It is approximately 45% inorganic material (mainly hydroxyapatite), 33% organic material (mainly collagen) and 22% water. Cementum is excreted by cementoblasts within the root of the tooth and is thickest at the root apex. Its coloration is yellowish and it is ...
In the tooth bud, regions where enamel formation is completed, the enamel organ gives rise to Hertwig's epithelial root sheath, composed of two epithelial layers derived from the external and internal epithelia. The sheath is irregularly fragmented in time and space as it promotes cementum deposition on the newly formed dentin.
The tooth germ is an aggregation of cells that eventually forms a tooth. [2] These cells are derived from the ectoderm of the first pharyngeal arch and the ectomesenchyme of the neural crest. [1] [3] [4] The tooth germ is organized into three parts: the enamel organ, the dental papilla and the dental sac or follicle.
The periodontium (from Greek περί (peri-) 'around' and -odont 'tooth') is the specialized tissues that both surround and support the teeth, maintaining them in the maxillary and mandibular bones. Periodontics is the dental specialty that relates specifically to the care and maintenance of these tissues. It provides the support necessary to ...