Dr. Mrinalini Agarwal
Dr. Mrinalini Agarwal, Subharti Dental College, SVSU DEFINITION
Alveolar process is the portion of the maxilla and mandible that forms and supports the tooth sockets (alveoli).
Dr. Mrinalini Agarwal, Subharti Dental College, SVSU 2 Dr. Mrinalini Agarwal, Subharti Dental College, SVSU 3 PARTS
The alveolar process consists : An external plate of cortical bone formed by haversian bone and compacted bone lamellae. The inner socket wall of thin, compact bone called the alveolar bone proper, which is seen as the lamina dura in radiographs. Cancellous trabeculae, between these two compact layers, which act as supporting alveolar bone.
Dr. Mrinalini Agarwal, Subharti Dental College, SVSU 4 Dr. Mrinalini Agarwal, Subharti Dental College, SVSU 5 LAMINA DURA
Dr. Mrinalini Agarwal, Subharti Dental College, SVSU 6 Histologically, it contains a series of openings called Cribriform plate through neuovascular bundles link the periodontal ligament with the cancellous bone. The interdental septum consists of cancellous supporting bone within a compact border.
Dr. Mrinalini Agarwal, Subharti Dental College, SVSU 7 SOCKET WALL
Consists of dense, lamellated bone, some of which is arranged in haversian systems, 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. Characterized by thin lamellae arranged in layers parallel to the root, with intervening appositional lines.
Dr. Mrinalini Agarwal, Subharti Dental College, SVSU 8
Dr. Mrinalini Agarwal, Subharti Dental College, SVSU 9 CANCELLOUS PORTION
Consists of trabeculae that enclose irregularly shaped marrow spaces lined with a layer of thin, flattened endosteal cell.
Dr. Mrinalini Agarwal, Subharti Dental College, SVSU 10 BONE MARROW
Yellow marrow: Majority of the area of jaws. Red Marrow: maxillary tuberosity, maxillary and mandibular molar and premolar areas, mandibular symphysis and ramus angle.
Dr. Mrinalini Agarwal, Subharti Dental College, SVSU 11 PERIOSTEUM & ENDOSTEUM The tissue covering the outer surface of bone is termed periosteum, whereas the tissue lining the internal bone cavities is called endosteum.
Dr. Mrinalini Agarwal, Subharti Dental College, SVSU 12 Periosteum : an inner layer (osteogenic) of osteoblasts surrounded by osteoprogenitor cells & an outer layer (fibrous) rich in blood vessels & nerves and composed of collagen fibers and fibroblasts. Endosteum composed of single layer of osteoblasts.
Dr. Mrinalini Agarwal, Subharti Dental College, SVSU 13 INTERDENTAL SEPTUM Consists of cancellous bone bordered by the cribriform plates of approximating teeth and the facial and lingual cortical plates. The distance between CEJ and crest of the alveolar bone: average of 1.08mm and may increase with age up to average of 2.81mm.
Dr. Mrinalini Agarwal, Subharti Dental College, SVSU 14 BONE COMPOSITION
Bone: 2\3rd inorganic matter, 1\3rd organic matrix. Inorganic matter is composed principally of Ca, phosphate, along with hydroxyl, carbonate, citrate, traces e.g. Na, Mg, & F. The mineral salts are in the form of hydroxyapatite crystals. Organic matrix: 90% by type I collagen with small amounts of non collagenous proteins such as osteocalcin, osteonectin.
Dr. Mrinalini Agarwal, Subharti Dental College, SVSU 15 BONE REMODELLING
Is the major pathway of bony changes in shape, resistance to forces, repair of wounds and calcium and phosphate homeostasis in the body. Involves coordination of activities of osteoblasts and osteoclasts. Interdependency of osteoblasts and osteoclasts in remodeling is called coupling.
Dr. Mrinalini Agarwal, Subharti Dental College, SVSU 16 REGULATION
Local factors Systemic factors Functional requirement hormonal of teeth and age ( parathyroid hormone, related changes calcitonin, vit D)
Dr. Mrinalini Agarwal, Subharti Dental College, SVSU 17 BONE FORMATION
Osteoblasts, produce the organic matrix of bone Alveolar bone is formed during fetal growth by intra-membranous ossification and consists of a calcified matrix with osteocytes enclosed within spaces called lacunae. The osteocytes extend processes into canaliculi that radiate from the lacunae.
Dr. Mrinalini Agarwal, Subharti Dental College, SVSU 18 BONE GROWTH
The bone matrix that is laid down by osteoblasts is nonmineralized osteoid.
Older osteoid located below the surface becomes mineralized as the mineralization front advances.
Bone resorption is caused by large, multinucleated cells osteoclasts present in the howship’s lacunae.
Dr. Mrinalini Agarwal, Subharti Dental College, SVSU 19 Dr. Mrinalini Agarwal, Subharti Dental College, SVSU 20 OSSEOUS TOPOGRAPHY
Bone contour normally conforms to the prominence of the roots, with intervening vertical depressions that taper toward the margin. Height and thickness of the facial and lingual bony plates are affected by the alignment of the teeth, angulation of the root to the bone, and occlusal forces.
Dr. Mrinalini Agarwal, Subharti Dental College, SVSU 21 EXOSTOSES
Dr. Mrinalini Agarwal, Subharti Dental College, SVSU 22 FENESTRATIONS & DEHISCENCE
Dr. Mrinalini Agarwal, Subharti Dental College, SVSU 23 FENESTRATIONS & DEHISCENCE
Isolated areas in which the root is denuded of bone and the root surface is covered only by periosteum and overlying gingiva are termed fenestrations. In these instances the marginal bone is intact When the denuded areas extend through the marginal bone, the defect is called a dehiscence.
Dr. Mrinalini Agarwal, Subharti Dental College, SVSU 24 CLINICAL SIGNIFICANCE
The cause of these defects is not clear. Prominent root contours, malposition, and labial protrusion of the root combined with a thin bony plate are predisposing factors. Important because they may complicate the outcome of periodontal surgery.
Dr. Mrinalini Agarwal, Subharti Dental College, SVSU 25