Alveolar bone . The alveolar process is the bone that forms and supports the dental alveoli. It consists of the inner wall of the alveoli, of thin, compact bone, called the alveolar bone itself ( cribriform lamina ).
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- 1 What is the alveolar bone?
- 2 Deposition
- 3 Morphology
- 4 Vascularization, Lymphatics and Nerves
- 5 Interdental Septum
- 6 Fenestrations and Dehiscences
- 7 Remodeling
- 8 Lability of the alveolar bone.
- 9 Mesial migration of the teeth and reconstruction of the alveolar bone
- 10 Occlusal forces and alveolar bone
- 11 Sources
What is the alveolar bone?
It is the supporting bone, which consists of spongy trabeculae, and vestibular and lingual tables of compact bone. The interdental septum consists of cancellous supporting bone enclosed within certain compact limits. It is a fine, compact bone with multiple and small perforations, through which blood vessels, nerves, and lymphatic vessels pass.
The surface of the external bone mass is covered by a thin layer of non-calcified bone matrix called the osteide, and this, in turn, is covered by a condensation of fine collagen fibers and cells, constituting the periosteum. Cavities within the bone mass, or formed by resorption, are lined by the endoste, which is identical in structure to the periosteum. These layers contain osteoblasts, which have the ability to deposit bone matrix and induce calcification and osteoclasts . Osteoclasts are large, multinuclear cells that are usually seen on the bone surface within eroded bone depressions, called Howship lagoons.. The wall of the alveolus is made up of lamellar bone, part of which is organized in the Haversian system and “fasciculated bone”. Fasciculated bone is the name given to the bone that limits the periodontal ligament, due to its content of Sharpey fibers .
Casi siempre, la forma del hueso alveolar puede predecirse con base en tres principios generales: 1. La posición, etapa de erupción, tamaño y forma de los dientes, los que determinan, en gran medida, la forma del hueso alveolar. 2. Cuando es sometido a fuerzas dentro de los limites fisiológicos normales, el hueso experimenta remodelación para formar una estructura que elimina mejor las fuerzas aplicadas. 3. Existe un grosor finito, menos del cual, el hueso no sobrevive y es reabsorbido+ El margen alveolar suele seguir el contorno de la línea cemento adamantina. Por esto, el festoneado del margen óseo es mas prominente en el aspecto facial de los dientes anteriores que en los molares y el hueso interproximal entre los dientes anteriores es piramidal, mientras que entre los molares es plano en sentido bucolingual.
Vascularization, Lymphatics and Nerves
The bone wall of the alveoli appears radiographically as a thin radiopaque line, called the lamina lamina dura or alveolar cortex. However, it is perforated by numerous ducts that contain blood vessels, lymphatics and nerves that establish the union between the periodontal ligament and the spongy portion of the alveolar bone.
It is made up of cancellous bone limited by the alveolar walls of neighboring teeth and the vestibular and lingual cortical plates.
Fenestrations and Dehiscences
Isolated areas where the root has been denuded of bone and the root surfaces covered only by the periosteum and gum are called fenestrations. In this case the bone is intact. When the denuded areas extend to the marginal bone, the defect is called dehiscence.
Under normal conditions, the teeth move in a mesial direction and erupt continuously to compensate for the reduction by attrition in their mesiodistal dimensions and occlusal height. These movements induce renewal of the surrounding alveolar bone. The position of the bone is observed more frequently in the apical third and in the distal aspect of the alveolus, while bone resorption occurs more frequently in the mesial aspect.
Alveolar bone lability.
In contrast to its apparent rigidity, the alveolar bone is the least stable of the periodontal tissues; its structure is constantly changing. The bone is reabsorbed in pressure areas and is formed in areas of stress. The cellular activity that affects the height, contour and density of the alveolar bone is manifested in three areas. 1) next to the periodontal ligament. 2) in relation to the periosteum of the vestibular and lingual tables and 3) next to the endostic surface of the medullary spaces.
Mesial migration of the teeth and reconstruction of the alveolar bone
With time and wear, the contact areas of the teeth flatten out and the teeth tend to move mesially. This is called physiological mesial migration.
Occlusal forces and alveolar bone
The bone is removed from where it is no longer needed and is added where new needs arise. When an occlusal force is exerted on a tooth through the bolus or in contact with its antagonist, several things happen, depending on the direction, intensity and duration of the force. The tooth moves into the resilient periodontal ligament, in which it creates an area of tension and compression. The vestibular wall of the socket and the lingual are slightly stretched in the direction of force. When the force is released, the tooth, ligament, and bone return to their original position.