Investing structure :
GINGIVA
Supporting structures:
PERIODONTAL LIGAMENT
CEMENTUM

• Definition :
The alveolar process is the portion of the maxilla and mandible that forms and supports the tooth sockets (alveoli).
• They are tooth depended structures
• It forms when the tooth erupts to provide the osseous attachment to the forming periodontal ligament and disappears gradually after the tooth is lost

Alveolar bone
Basal bone

Alveolar process consists of
1. An external plate of cortical bone formed by compacted bone lamellae
2. The inner socket wall of thin compact bone called the alveolar bone proper which is seen as the laminadura in radiographs . (cribri form plate)
3 .
Cancellous trabaculae , between these two compact layers, which act as supporting alveolar bone.

ALVEOLAR BONE
ALVEOLAR BONE
PROPER
SUPPORTING ALVEOLAR
BONE
LAMELLATED BONE CORTICAL PLATE
BUNDLE BONE SPONGY BONE

• The socket wall consists of dense, lamellated bone and bundle bone .
• Bundle bone is the term given to bone adjacent to the periodontal ligament that contains a great number of
Sharpey's fibers
• Thin lamellated bone arranged in layers parallel to the root.

• The interdental septum consists of cancellous bone/ spongy bone bordered by the socket wall cribriform plates of approximating teeth and the facial and lingual cortical plates.
• If the interdental space is narrow, the septum may consist of only the cribriform plate.
• If roots are too close together, an irregular "window" can appear in the bone between adjacent roots.
• In healthy mouths the alveolar crest is around 1.5 to 2 mm below the CEJ.

• 2 basic constituents:
1)BONE CELLS :
• Osteoblasts
• Osteoclasts
• Osteocytes
2) Extra cellular matrix

• Inorganic : composed of minerals such as calcium, phosphate
along with hydroxyl, carbonate, citrate and trace amounts of other ions such as sodium, magnesium and fluorine.
• The minerals are in the form of hydroxy apatite crystals .
• The organic matrix consists of 90% of Type I collagen with small amounts of non-collagenous proteins such as sialoprotein, osteocalcin, osteonectin, bone morphogenic proteins, proteoglycans and glycoprotiens.

PERIOSTEUM AND ENDOSTEUM
• The tissue covering the outer surface of the bone is termed as
Periosteum
• The periosteum consists of an inner layer composed of osteoblasts surrounded by osteoprogenitor cells, and an outer layer rich in blood vessels and nerves and composed of collagen fibers and fibroblasts.
• The tissue lining the internal bone cavities is called as
Endosteum
• The endosteum is composed of a single layer of osteoblasts and sometimes a small amount of connective tissue.

in which the root is denuded of the bone and the root is covered only by the Periosteum and overlying gingiva
• Marginal bone is
• Commonly seen on the mesiobuccal root of the maxillary first molar and maxillary canines

DEHISCENCE :
• These are denuded areas of the bone on the roots extending through the marginal bone
• More on the facial and in the anterior teeth than on the posterior teeth
• Frequently bilateral
Predisposing factors are
• Allignment of the tooth
• Angulation of the root to the bone
• Occlusal forces and malposition