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ORAL MIC ANA LEC (March 1)

LVEOLAR BONE

lveolar Process where tooth is embedded

ONE Specialized connective tissue composed of intercellular substance and

osteocytes with its processes in lacunae and canaliculi Acts as an anchorage because it is where roots are embedded (alveolar socket) Calcified tissue; originate from dental sac (gives rise to PDL, cementum and

alveolar bone)

omposition 67% Inorganic (Hydroxyapatite) 33% Organic

o 28% collageno 5%

Osteocalcin Sialoprotein Phosphoprotein Osteonectin Bone specific protein

unctions of Bone. Skeletal function of support, protection, locomotion and attachment of muscles. Bone constitutes an important reservoir of minerals. Bone is for hemopoiesistructural Elements of Bone. Bone Cells

a. Osteoblasts forms boneb. Osteocytes maintains bonec. Osteoclasts resorbs bone

. Bone Matrix

. Sharpeys Fibers

. Blood vessels, nerves, lymph vessels (Haversian Canals)istological Arrangement of Mature Bone

All bones are a dense sheet of compact bone and a central medullary cavity. The marrow cavity is interrupted throughout

I. Compact Bone- are dense outer sheet that are closely packed3 Distinct Layering:

a. Circumferential lamellab. Concentric lamellac. Interstitial lamella

II. Spongy Bone- flattened spicules surrounding the spaces known as marrow spacescontaining the bone marrow

ircumferential Lamellae - enclose the entire adult bone, forming i ts outer perimeter

oncentric Lamellae - make up the bulk of compact bone and form the basicmetabolic unit of bone, the osteon

nterstitial Lamellae - interspersed between adjacent concentric lamellae and fill thepaces between them;fragments of preexisting concentric lamellae and can take up

multitude of

Osteon - basic metabolic unit of bone generally oriented in the long axis of bone

aversian Canal - canal lined by a single layer of bone cells at the outer of ansteon; each canal; houses a capillary

olkmans Canal - channels that connect adjacent haversian canal;contains bloodessels

eriosteum osteogenic connective tissue membrane that surrounds every compactone; consists of 2 layers

Inner layer consists of bone cells; their precursors and a rich microvascusupply

Outer layermore fibrous, gives rise toBone Formation (Ossification)1. Endochondral (Intracartilaginous) Bone Ossification

a. Has a precatilaginous stage2. Intramembranous Bone Ossification

a. Mandible and maxilla3. Sutural Bone GrowthALVEOLAR BONE Is the bony portions of the maxillae and mandible in which the roots of the

functioning teeth are located Processus Alveolaris in the maxilla Pars Alveolaris in the mandible Develop along with formation and eruption of the teeth and are resorbed af

teeth are lost Morphology depends on the size, shape and position of teethFunctions1. Acts as the anchoring of teeth within the alveoli2. Absorption and distribution of occlusal pressures produced by intermittent

contacts during chewing, swallowing, speech and parafunctional activities as grinding and chewing

Structure of Alveolar Bone

1.

Cortical Plate outermost parta. Alveolar bone proper or lamina2. Spongiosa spongy boneCortical Plate Outer bony plate of varying thickness, which is the outside wall of the maxi

and mandible, covered with periosteum Continuous with the lamina cribriformis at the orifice of the alveoli alveola

crest Consists of haversian systems (osteons) and interstitial lamellae Thicker in the mandible than maxilla Generally greater on the lingual than on the buccal/facialAlveolar Bone Proper or Lamina (cribriformis) An inner, heavily perforated bony lamellae, forming the alveolar wall In radiograph, appears as radioopaque line distinct from the adjacent sponLamina Dura Contains osteons like other cortical bone, but is distinguished by the presen

Bundle Bone

Bundle Bone Multiple layers of bone parallel to surface of alveolar wall which are penetr

by bundles ofSharpeys Fibers embedded nearly right angle

Spongiosa Are spongy (or cancellous/trabecullar) bone between the 2 bony plates an

between the lamina cribriformis of adjacent teeth or roots Consists of delicate trabeculae, between which are marrow spaces, filled m

with fatty marrow Regions of maxillary tuberosity and the angle of mandible, erythropoietic VASCULAR SUPPLY OF ALVEOLAR PROCESS Alveolar process of the maxilla

o Anterior and posterior alveolar arteries (branch from the maxillainfraorbital arteries)

Alveolar process of the mandibleo Inferior alveolar arteries (internal)o Periosteal branches of submental and buccal arteries (external)

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RAL MUCOSA

Type of mucosa that covers oral cavity Oral cavity is lined with an uninterrupted mucous membrane, which is continuous with skin near the vermillion

ASTICATORY MUCOSA Free and attached gingival and hard palate comes in primary contact with food during mastication and iskeratinized (Keratinized epithelium)

NING MUCOSA The lips, cheeks, vestibule, floor of the mouth, soft palate. It does not function in mastication and therefore haslittle attrition. It is soft, pliable and non-keratinized (Non-keratinized Epithelium)

PECIALIZED MUCOSA On the dorsal surface (dorsum) of the tongue. It is covered with cornified epithelial papillae; presence ofpapillae

UNCTIONS OF ORAL MUCOSA Protection acts as major barrier to microorganisms Sensation receptors that respond to temperature, touch, pain, taste, initiates reflexes such as swallowing,gagging and salivation Secretion saliva, contributes to the maintenance of moist surface Permeability and Absorptionthinnest epithelial regions Thermal Regulation

ENERAL HISTOLOGIC CHARACTERISTICS OF ORAL MUCOSAMain Tissue Components

Oral Epithelium stratified squamous epitheliumLamina Propia or Corium underlying connective tissue layer

ral Epitheliumeratinized Surface Epithelium Stratum corneum - dead cells without nuclei Stratum granulosum keratohyalin granules Stratum spinosum Prickle cell layer Stratum basaleon-Keratinized Surface Epithelium Stratum basale site of most cell divisions

o Cuboidal or columnar cells containing separate tonofilaments and other cell organelles Stratum intermedium slightly increase in cell size as well as accumulation of glucose in all of the surface layero Rare occasion, keratohyalin granules can be seen Stratum superficial (superficial layer) cells appear slightly flattened than in the preceding layers and contain

dispersed tonofilaments and nuclei, the number of other cell organelles having

ayers of Lamina Propia/Coriumapillary Layer or Connective Tissue Papillae Indents and interdigitates with the epithelium (rete r idges/pegs) May be short or absent in some mucosaeticular Layer Consists of densely arranged connective tissue fibers (reticular)NING MUCOSAps Lined by a moist, stratified squamous non -keratinized epithelium Non-keratinized mucosa is distinguished by a red border known as vermillion border

3 Reason why vermillion border is red:o Epithelium is thino This epithelium contain eleidin, which is transparento The blood vessels are near the surface of the papillary layer

oft Palate Stratified squamous non-keratinized epithelium Highly vascularized More pink than the mucosa of the keratinized hard palate lamina propia contains many small blood vessels Beneath the connective tissue of the lamina propia is the submucosa which contains muscles and mucousglands

heeks Mucosa is same as the lips and soft palate, however, the submucosa containing fat cells and mixed glands(seromucous) located within and between the muscle fibers The presence of these glands is a unique feature of the cheeks

entral Surface of the Tongue (under) Lining mucosa also contains lamina propia and submucosa In the submucosa, muscle fibers are located under the surface of the tongueoor of the Mouth Non-keratinized mucous membrane Covering appears loosely attached to the lamina propia in contrast to the mucosa of the central surface of the

tongue which is firmly attached Presence of minor salivary glands and right and left major mucous glands, the sublingual glandsNGIVA

TERDENTAL GINGIVA Firmly attached Pointed and not blunt Pale pink (red inflammation)REE GINGIVA A narrow band of tissue that follows the scalloped contour of the necks of the teeth and the CEJ Free because it can be moved mechanically along tooth surface as well as away from the tooth Has an epithelial attachment maintained by junctional epithelium along the tooth surface Separated from the attached gingival by a slight indentation called the Free Gingival Groove, whose level

corresponds approximately to that of the bottom of the gingival sulcus

Marginal Gingivao Part of free gingival that tapers to a knife-like edge extending along the cervical level of

tooth on labial or buccal an d lingual surfaces Interdental Gingival Papilla

o Bulges of gingival tissue on all occlusal direction in between teeth Interdental Col

o Constriction in between the facial and lingual interdental gingival papilla Gingival Sulcus

o Shallow groove extending around the circumference of the tootho Depth varies from 0.6mm and has the average depth of 1.8mm

ATTACHED GINGIVA Part attached to the teeth and alveolar bone It is bounded coronally by the free gingival groove and apically by the mucogingival junctionDENTOGINGIVAL JUNCTION Represents a unique anatomic feature concerned with attachment og the gingival to the tooth Ectodermal in origin Consist of 3 Fundamental Compartments

o Junctional epitheliumo Oral sulcus epitheliumo Oral

GINGIVAL LIGAMENT OR SUPRA-ALVEOLAR FIBER APPARATUS Dentogingival fibers Dentopeiosteal fibers Alveologingival fibers Circular and semicircular fibers Transseptal fibers Transgingival and intergingival fibers Interpapillary fibers Periosteogingival fibers Intercircular fibers

Dentogingival Fibers Most numerous, consists of 3 groups

o First group extends from the cementum in an obliquely coronal directiono Second group streams horizontal from cementum into the free marginal g ingivalo Third group many of which run parallel with the dentoperiosteal fibers

Dentoperiosteal Fibers Insert into the supraalveolar cementum at the same level as the transseptal fib ers, pass apically over th

of the alveolar bone into the periosteum of the outer and inner plates of the alveolar process

Alveologingival Fibers Insert into the (rest or nest?) of alveolar bone, course coronally and enter the free and attached section

marginal and interdental gingival

Circular and SemicircularCircular Small group of fibers that forms a band around the neck of the tooth helping to bond the free gingival in

toothSemicircular Encircle only the vestibularTransseptal Fibers Cementum to cementum attachment Also known as interdental fibers Bind the supralaveolar cementum of one tooth to that of the adjacent tooth Implicated as a major cause of ost-retention relapse of orthodontically positioned teethTransgingival and Intergingival FibersTransgingival Identical with semicircular, insert interdentally into a supraalveolar cementum, pass obliquely through th

interdental tissue stream into the free gingival of the adjacent tooth where they may uniteIntergingival From a continuous series of fibers running under the epithelium along both the vestibular and oral aspe

the dental arch converging distal to the last molar

Interpapillary Fibers Cross through the free portion or interdental gingival tissue in an orovestibular direction to tie the oral a

vestibular gingival papillae together

HARD PALATE Roof of the mouth and is supported by the palatine processes of the maxilla and horizontal parts of the

bone At the level of the alveolar tuberosity, it joins the soft palate (posterior)DORSUM OF TONGUE Circumvallate papillae biggest Fungiform papillae mushroom appearance Foliate papillae lateral posterior side of the tongue; contains taste b udsTASTE BUDS Microscopically visibleTip (most) sweetTip saltyLateral (sides) sourPosterior (back) bitter