Human tooth of tooth loss can be rapid since enamel is very thin in this region of the tooth. A common source of this type of tooth wear is excessive force when using a toothbrush. Erosion is the loss of tooth structure due to chemical dissolution by acids not of bacterial origin. Signs of tooth destruction from erosion is a common characteristic in the mouths of people with bulimia since vomiting results in exposure of the teeth to gastric acids. Another important source of erosive acids are from frequent sucking of lemon juice. Abfraction is the loss of tooth structure from flexural
Human tooth development through cementum. NGF-R is present in the condensing ectomesenchymal cells of the dental papilla in the early cap stage tooth germ and plays multiple roles during morphogenetic and cytodifferentiation events in the tooth. There is a relationship between tooth agenesis and absence of the peripheral trigeminal nerve (see Hypodontia). All stages (bud, cap, bell, crown), growth and morphogenesis of the teeth are regulated by a protein called sonic hedgehog. Various phenotypic inputs modulate the size of the teeth. Parathyroid hormone is required for tooth eruption. The following tables present the development timeline of human teeth. Times for the initial calcification