پاورپوینت انگلیسی Structures of Teeth به همراه ترجمه فارسی

نوع فایل: PowerPoint

تعداد اسلاید (ها): 22

چکیده ای از متن:

Teeth are composed of:

enamel

the pulp-dentin complex

cementum

Enamel formation

(amelogenesis)

ameloblasts

embryonic

germ layer

ectoderm Enamel covers the anatomic crown of the tooth varies in thickness in different areas It is thicker at the incisal and occlusal areas of a tooth and becomes progressively thinner until it terminates a the cementoenamel junction (CEJ)

The thickness a varies from one class of tooth to another 2 mm incisal ridges of incisors 2.3 to 2.5 mm cusps of premolars 2.5 to 3 mm cusps of molars can approach zero where the junction is fissured.

Chemically, enamel is a highly mineralized crystalline structure mineral constituent (90%- 92% by volume) Organic matrix proteins (1%-2%) water (4%-12%)

Structurally, enamel is composed of millions of enamel rods or prisms ("tail" portion &”head" portion) rod sheaths(cementing inter-rod substance )between crystallites is partially organic material

The rods vary in number from approximately: 5 million for a mandibular incisor to about 12 million for a maxillary molar The rods are densely packed and intertwined in a wavy course each extends from the DEJ to the external surface of the tooth the rods are aligned perpendicularly to the DEJ and the tooth surface in the primary and permanent dentitions except in the cervical region of permanent teeth h((oriented outward in a slightly apical direction

فهرست مطالب:

Teeth are composed of

Enamel

Gnarled enamel

Hunter-Schreger bands

Enamel lamellae

Enamel tufts

incremental striae of Retzius

DEJ

The End