| Alveolar process |
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Left maxilla. Outer surface. (Alveolar process visible at bottom.)
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Cartilages of the nose, seen from below. (Alveolar process of maxilla visible at bottom.
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| Details |
| Identifiers |
| Latin |
Processus alveolaris |
Dorlands
/Elsevier |
p_34/12667282 |
| TA |
A02.1.12.035 |
| FMA |
52897 |
| Anatomical terms of bone
[edit on Wikidata]
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The alveolar process ([1][2]) (alveolar bone) is the thickened ridge of bone that contains the tooth sockets (dental alveoli) on bones that hold teeth. In humans, the tooth-bearing bones are the maxillae and the mandible.[3]
Contents
- 1 Structure
- 2 Clinical significance
- 2.1 Developmental disturbances
- 2.2 Pathology
- 3 Additional images
- 4 See also
- 5 References
- 6 External links
Structure
On the maxillae, the alveolar process is a ridge on the inferior surface, and on the mandible it is a ridge on the superior surface. It makes up the thickest part of the maxillae.
The alveolar process contains a region of compact bone adjacent to the periodontal ligament (PDL), which is called the lamina dura when viewed on radiographs. It is this part which is attached to the cementum of the roots by the periodontal ligament. It is uniformly radiopaque (or lighter). Integrity of the lamina dura is important when studying radiographs for pathological lesions.
The alveolar bone or process is divided into the alveolar bone proper and the supporting alveolar bone. Microscopically, both the alveolar bone proper and the supporting alveolar bone have the same components: fibers, cells, intercellular substances, nerves, blood vessels, and lymphatics.
The alveolar bone proper is the lining of the tooth socket or alveolus (plural, alveoli). Although the alveolar bone proper is composed of compact bone, it may be called the cribriform plate because it contains numerous holes where Volkmann canals pass from the alveolar bone into the PDL. The alveolar bone proper is also called bundle bone[citation needed] because Sharpey fibers, a part of the fibers of the PDL, are inserted here. Similar to those of the cemental surface, Sharpey fibers in alveolar bone proper are each inserted at 90 degrees, or at a right angle, but are fewer in number, although thicker in diameter than those present in cementum. As in cellular cementum, Sharpey fibers in bone are generally mineralized only partially at their periphery.
The alveolar crest is the most cervical rim of the alveolar bone proper. In a healthy situation, the alveolar crest is slightly apical to the cementoenamel junction (CEJ) by approximately 1.5 to 2 mm.[3] The alveolar crests of neighboring teeth are also uniform in height along the jaw in healthy situation.[4]
The supporting alveolar bone consists of both cortical bone and trabecular bone. The cortical bone, or cortical plates, consists of plates of compact bone on the facial and lingual surfaces of the alveolar bone. These cortical plates are usually about 1.5 to 3 mm thick over posterior teeth, but the thickness is highly variable around anterior teeth.[3] The trabecular bone consists of cancellous bone that is located between the alveolar bone proper and the plates of cortical bone. The alveolar bone between two neighboring teeth is the interdental septum (or interdental bone).[4]
Features
The mineral content of alveolar bone is mostly calcium hydroxyapatite, which is similar to that found in higher percentages in both enamel and dentin, but is most similar to the levels in cementum (50%). Like all bone, mature alveolar bone is by weight 60% mineralized or inorganic material, 25% organic material, and 15% water. The minerals of potassium, manganese, magnesium, silica, iron, zinc, selenium, boron, phosphorus, sulfur, chromium, and others are also present but in smaller amounts. Alveolar bone is more easily remodeled than cementum, thus allowing orthodontic tooth movement. When viewing a stained histological section, the remodeled alveolar bone shows arrest lines and reversal lines, as does all bone tissue.[4]
Clinical significance
Developmental disturbances
The developmental disturbance of anodontia (or hypodontia, if only one tooth), in which tooth germs are congenitally absent, may affect the development of the alveolar processes. This occurrence can prevent the alveolar processes of either the maxillae or the mandible from developing. Proper development is impossible because the alveolar unit of each dental arch must form in response to the tooth germs in the area.[4]
Pathology
After extraction of a tooth, the clot in the alveolus fills in with immature bone, which later is remodeled into mature secondary bone. However, with the loss of teeth, a patient becomes edentulous, either partially or completely, and the alveolar bone undergoes resorption. The underlying basal bone of the body of the maxilla or mandible remains less affected, however, because it does not need the presence of teeth to remain viable. The loss of alveolar bone, coupled with attrition of the teeth, causes a loss of height of the lower third of the vertical dimension of the face when the teeth are in maximum intercuspation. The extent of this loss is determined based on clinical judgment using the Golden Proportions.[4]
The density of the alveolar bone in a given area also determines the route that dental infection takes with abscess formation, as well as the efficacy of local infiltration during the use of local anesthesia. In addition, the differences in alveolar process density determine the easiest and most convenient areas of bony fracture to be used, if needed during tooth extraction of impacted teeth.[4]
During chronic periodontal disease that has affected the periodontium (periodontitis), localized bone tissue is also lost.
Additional images
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This X-ray film reveals some bone loss on the right side of the mandible. The associated teeth exhibit poor crown-to-root ratios and may be subject to secondary occlusal trauma.
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Alveolar process of maxilla
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Alveolar process of mandible
See also
- Dental alveolus
- Periodontium
- Periodontal disease
References
- ^ OED 2nd edition, 1989 as /'ælvi:ələ(r)/.
- ^ Entry "alveolar" in Merriam-Webster Online Dictionary
- ^ a b c Ten Cate's Oral Histology, Nanci, Elsevier, 2013, page 219
- ^ a b c d e f Illustrated Dental Embryology, Histology, and Anatomy, Bath-Balogh and Fehrenbach, Elsevier, 2011, page 176
External links
- Photo of model at Waynesburg College skeleton/alveolarprocess
- "Anatomy diagram: 34256.000-1". Roche Lexicon - illustrated navigator. Elsevier. Archived from the original on 2014-01-01.
- Diagram at case.edu
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The facial skeleton of the skull
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| Maxilla |
| Surfaces |
- Anterior: fossae (Incisive fossa, Canine fossa)
- Infraorbital foramen
- Anterior nasal spine
- Infratemporal: Alveolar canals
- Maxillary tuberosity
- Orbital: Infraorbital groove
- Infraorbital canal
- Nasal: Greater palatine canal
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| Processes |
- Zygomatic process
- Frontal process (Agger nasi, Anterior lacrimal crest)
- Alveolar process
- Palatine process (Incisive foramen, Incisive canals, Foramina of Scarpa, Incisive bone, Anterior nasal spine)
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| Other |
- Body of maxilla
- Maxillary sinus
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| Zygomatic |
- Orbital process (Zygomatico-orbital)
- Temporal process (Zygomaticotemporal)
- Lateral process (Zygomaticofacial)
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| Palatine |
| Fossae |
- Pterygopalatine fossa
- Pterygoid fossa
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| Plates |
- Horizontal plate (Posterior nasal spine)
- Perpendicular plate (Greater palatine canal, Sphenopalatine foramen)
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| Processes |
- Pyramidal
- Orbital
- Sphenoidal
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| Mandible |
| Body |
- external surface (Mandibular symphysis, Lingual foramen, Mental protuberance, Mental foramen, Mandibular incisive canal)
- internal surface (Mental spine, Mylohyoid line, Sublingual fovea, Submandibular fovea)
- Alveolar part
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| Ramus |
- Mylohyoid groove
- Mandibular foramen
- Angle
- Coronoid process
- Mandibular notch
- Condyloid process
- Pterygoid fovea
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| Nose |
- Nasal bone
- Nasal foramina
- Inferior nasal concha
- Maxillary process
- Vomer
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| Other |
- Lacrimal
- Posterior lacrimal crest
- Lacrimal groove
- Lacrimal hamulus
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