Organo de Esmalte

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Anatomía del Organo de Esmalte

Histología del Organo de Esmalte - Copyright RVC 2008
Capas del Organo de Esmalte - Copyright RVC 2008
Fibras Thomes' - Copywright RVC 2008

Los componentes principales que forman el órgano del esmalte son:

  • Epitelio externo
  • Retículo estrellado- células en forma de estrellas que extienden entre las capas epiteliales interior y exterior. Tiene la apariencia del tejido conectivo, pero es de origen epitelial.
  • Epitelio interno convierte en la capa de ameloblastos que secretan esmalte

Componentes

El órgano del esmalte tiene muchos componentes diferentes. Estos consisten de:

Corona

La corona está cubierta por el esmalte. Se reúne a la raíz en la unión cemento-esmalte.

La corona de los incisivos tienen una sola cúspide. La corona de los molares tienen hasta cuatro cúspides para la trituración de los alimentos.

Raíz

Los dientes pueden tener una o más raíces. El ángulo de bifurcación es el punto donde las raíces se separan. La raíz termina en una punta que es donde los nervios, vasos sanguíneos y linfáticos viajar a la pulpa dental. Dientes hipsodontos pueden tener raíces abiertos (aradicular) por ejemplo, en conejos que tienen crecimiento continuoso.Dientes hipsodontos pueden tener tambíen raíces cerradas (radicular) por ejemplo, en caballos cuando el crecimiento disminuye con la edad. Dientes brachidontos no tienen capacidad de crecimiento y las raíces están cerrados.

Diferencias Entre las Especies

El ápice tiene un único agujero en perros y gatos. Queda abierta en los herbívoros. En el caballo, el ápice se cierra con el envejecimiento del animal. Perros braquiocefálicos a menudo tienen raíces fusionadas. Incisivos equinos tienen las raíces fusionados. En los caninos del caballo, el tamaño de la raíz es mucho más grande que la corona.

Hueso Alveolar

The alveolar processes of the jaw consists of the hueso alveolar, trabecular bone and compact bone.

The densest bone called the cribiform plate lines the alveolus. This appears white on radiographs and is referred to as the lamina dura.

Lamina Dura

The lamina dura lines the hueso alveolar. If uninterrupted, it indicates good dental health.

The lamina dura is seen as a white line radiographically.

Esmalte

Enamel has an ectodermal origin. It is synthesised by ameloblastos. It is very hard, densly calcified and acellular, therefore cannot regenerate.

Complicated enamel folding occurs in teeth where the coronas are high. Enamel forming secretions pass through processes of apical cytoplasmic extension called Thomes' Fibres.

Dentina

Dentine is a calcified, collagen rich matrix. It is synthesised by odontoblastos.

Secondary dentine is produced throughout life and increases with rate of repair. It is darker in colour than primary dentine.

Cemento

Cementum is synthesised by cementoblastos. It is calcified tissue and lacks regular organisation. Collagen fibres extend from the cementum into the ligamento periodontal to fasten the tooth in its socket. Cementum is relatively immune to pressure erosion, therefore the tooth can be be romedelled in its socket.

Pulpa Dental

Pulp fills the dental cavity. It is a delicate connective tissue bordering the odontoblasto layer. It is highly vascularised and contains a lymphatic plexus.

Pulp allows pain sensation to thermal, mechanical and chemical stimulants. Most of the nervous supply is sensory, with some vasomotor input.

Ligamento Periodontal

The collagen fibre bundles are called Sharpey's fibres. The fibres insert into the hueso alveolar and cemento of the tooth.

There are 3 categories: gingival, trans-septal and alveolodental. There are evenly distributed blood vessels and nerve fibres transmitting thermal, pain and pressure sensation. Some species can also sense proprioception in the periodontal ligament.


Main Cells

Histología de Ameloblasto - Copywright RVC 2008

Ameloblastos

Ameloblasts are cells in the enamel organ which forms the tooth. They secrete esmalte.

Epithelial cells line the inner surface of the enamel organ. Ameloblasts are derived from epithelium and form a single layer of very long columnar cells that are hexagonal in cross section. They have elongated, basally sited nuclei. They synthesise esmalte which forms the corona of each tooth. They maintain connections with the newly synthesised esmalte through cellular projections called Thomes' fibres.

Esmalte is acellular so once the connection with the ameloblasts via the Thomes' fibres is lost (upon eruption), the esmalte matrix cannot be remodelled.

Odontoblastos

The odontoblasts are cells in the enamel organ which forms the tooth. They secrete dentina.

Odontoblasts are derived from mesenchyme and are composed of a single layer of elongated columnar cells. They are at the dental-pulp border. They secrete dentina which is a mineralised matrix of collagen I, dentina and proteins.

The first layer of dentina is formed on the enamel organ. As production increases, the odontoblasts are displaced from the esmalte. It is a major part of the tooth structure and is produced continually by the odontoblasts. The rate of dentina synthesis is increased during repair as it is innervated (but still acellular).

Cementoblastos

Cementoblasts are cells in the esmalte organ which forms the tooth. They secrete cemento.

Epithelial cells are present near the distal end of the cup. They become follicle cells. Cementoblasts synthesise cemento which mostly contains collagen I.

Cemento surrounds the dentina of the raíz. Cemento is acellular and not readily absorbed.

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