Ligament periodontalOs alveolarGingieEpiteliu gingivalan gingivalForamen apicalSmalPulpDentinCementCanal

Organul dentarDinteleCoroanColetRdcin Foramen apicalPeriodontul CementLigament periodontalOs alveolarGingie

Enamel - the translucent outer layer of the tooth. It is the hardest substance in the human body.

Consists of: - 96% inorganic salts- 4% organic substances-glycoproteins enamelin.This substances are packed in specific hexagonal prisms. Enamel prisms are striated and the striations occur regularly every 4m.

Striae of Retzius can be seen

Dentin - forms the bulk of the tooth. It supports enamel and acts as the skeleton of the tooth. It is the second hardest tissue in the human body. Consists of:-72% inorganic salts (Ca phosphate, Mg phosphate)

-28% organic substances (collagen type I, proteoglycans and glycoproteins).Contains unique radial striations, called dentinal tubules. Each tubule is filled with an elongated cellular process of an odontoblast, and nerve endings.

Cementum is the third mineralized tissue of the tooth and is as hard as bone is, but has no Haversian systems.

Consists of: 50% inorganic salts 50 % organic substances.There are 2 types of cementum:I. Cellular contains cementocytes and cementoblastsII. Acelular has no cells.Cementum can be formed throughout life.

Collagen fibers of the periodontal ligament insert into the cementum and also into the bone of the alveolus attaching the tooth to the jaw.

Bone - alveolar bone forms the tooth socket and provides it with support.

Pulp - loose connective tissue, located in the center of the tooth, it contains the arteries, veins and nerves.

Root canal - canal in the root of the tooth where the nerves and blood vessels travel through.

Componente Pulpa dentaresut conjunctiv lax la tineri, fibros la vrstniciSF bogat, numeroase fibre nervoaseStratul periferic: odontoblasteDentinaOdontoblastCanaliculi dentinaliSmalulPrismele smaluluiAmeloblastLeziunile: ireversibile

Bud stageCap stageBell stageHitogenesis

Bud stage- oral epithelium proliferates and a plate of epithelium grows into the underlying ectomesenchyme and form the dental lamina. Shortly after appearance dental lamina increases its mitotic activity and form epithelial structures,called tooth buds.

Cap stage -mitotic activity of the buds increases , forming a cap-shaped enamel organ-enamel organ is composed of 3 layers:The convex outer enamel epitheliumThe concave inner enamel epitheliumStellate reticulum -ectomesenchymal cells form the dental papilla -additional ectomesenchymal cells surround the tooth germ and form the dental sac-dental lamina for permanent tooth is formed

Bell stage cells at the periphery of the dental papilla differentiate into odontoblasts and begin to elaborate predentin.Cells of the IEE differentiate into ameloblasts which begin to elaborate enamelThe dentin and enamel adjoin each other and the junction between them is called the dentino-enamel junction.

Histogenesis of tooth tissues

Odontoblastul Celul columnar Dispuse pe un singur rnd la periferia pulpei dentareNucleu ovalar, la polul pulparCitoplasm cu organite nespecificePrelungire inclus n canaliculii dentinaliSecret precursorii dentinei

esuturile de susinereCementAcoper dentina rdciniiCelular i acelularCementocite i matriceLigament periodontalSolidarizeaz cementul la osul alveolarFibroblaste, fibre colagene i oxitalaniceOs alveolaresut osos imatur de tip spongiosRemodelare Gingie