Perio 1

Cementum resorption

Causes: -Local: trauma, orthodontic movement, pressure, cysts, tumors, etc. -Systemic: resorption, hypothyroidism, paget's disease

Sulcular fuild (GCF) as a diagnostic marker

Hydrogen sulfide indicates perio disease Beta-glucuronidase indicates breakdown of connective tissue

Apical Fibers

Radiate in an irregular pattern from cementum to bone

Cementicle oragins

-Calcified epithelial rests -Small spicules of bone -Calcified sharpey's Fibers -Calcified thrombosed vessels

Cell-Basal Lamina

Hemidesmosome Synthesis of basal lamina components takes place here

Interdental Gingiva Max Height for fill-in/ equation

If contact to bone distance is greater that 5mm, gingiva will not fill in. Every 1mm after 5mm decreases regeneration by 50% (ex. 6mm =50%, 7mm =25%)

Sulcular gingiva will keratinize if_____

If exposed to oral cavity, or if bacterial flora is totally eliminated. Irritation of sulcus prevents keratinization

Oxytalan Fibers

Immature form of elastin Fibers run parallel to vertical root surface Thought to regulate vascular flow by laying down scaffolding for blood vessles

Mast cells

Small round or oval Cytoplasmic granuels Contain heparin and histamine Release histamine into extracellular compartment

Nerves supplying PDL

Superior alveolar nerve Inferior alveolar nerve

Main gingival blood supply

Superior and inferior alveolar arteries. -Branches from the apical vessels -Branches from intra-alveolar vessels -Branches from the gingival vessels

Periodontal Ligament Principal Fibers (Sharpey's Fibers)

Terminal portion of principal fiber. Inserts into cementum and bone. Compased of type 1 collagen.

Sulcular Fluid (GCF) drug clearance

Tetracyclines are excreted through GCF at a rate 2-10x higher than in serum. (This allows high drug concentration to be delivered to perio pockets)

Free gingival groove

Narrow ridge that runs parallel to Free gingival margin. It is Rarely present

Gingival epithelium type

Stratified squamous epithelium

Junctional epithelium layers

3-4 in early life 10-29 in later years

Percentage of population with gingival stippling

40%

Alveolar mucosa

Mucosa covering basal part of alveolar process, and continuing into vestibular area. Movable.

Celluar cementum

Formed after tooth reaches occlusal plane Less calcified Smaller portion of sharpey's fibers

Acelllar cementum

Formed before tooth reaches occlusal plane Covers cervical 3rd of root 30-230 um thick Made of sharpey's fibers

When running a probe along gingiva, a fold forms at the beginning of the ________

Free gingiva

Attached gingiva width is greatest and least in which regions?

Greatest: Incisor region Least :posterior segments

Architectural integrity of gingival epithelium

Cell-cell attachments basal lamina keratin cytoskeleton

periodontal ligament

Connects root of tooth to bone 0.2mm wide

Internal basal lamina is composed of:

DAT cells and underlying connective tissue (laminin, type 8 collagen, proteoglycans) IBL is 3x thicker than EBL

Dehiscences

Denuaded area that edxtends through arginal bone

Macrophages

Derived from monocytes Horse-shoe or kidney shaped nucleus Contains phagocytosed material

Cell-Cell attachments of gingival epithelium

Desmosomes Adherans junctions Tight junctions Gap junctions

Major cell type of gingival epithelium

Keratinocyte

Diagnosis of Perio Disease

Measure from CEJ to base of the pocket

Functions of gingival epithelium

Mechanical, chemical, water and microbial barrier Signaling functions

What causes normal brown pigmentation on gingiva?

Melanocytes located in basal epithelium

Col

valley-like depression in the interdental gingiva that lies directly apical to the contact area

Length of the junctional epithelium

Ranges from 0.25-1.35mm long

Organic Matrix composition

Consists of mainly collagen type 1

Two components of Ground Substance

Glycoaminoglycans (ex. hyaluronic acid) Glycoproteins (ex. fibronectin and laminin)

3 components of Alveolar bone process

1. External cortical bone plate 2. Middle cancellous trabeculae 3. Inner socket compact bone

PDL neural terminations

1. Free endings - sensory, pain perception 2. Ruffians corpuscles - knob like, mechanoreceptors 3. Meissener's corpuscles - tactile, midroot 4. Spindle type nerve endings - apex

Socket wall composition

Bundle bone (bone adjacent to PDL, contains great number of Sharpey's fibers)

Junctional epithelium

Attaches gingiva to tooth surface Can weakly attach to anything, including implants and fillings.

Cementum

Calcified avascular tissue that covers anatomic root 2 types -Acellular (primary) -Cellular (secondary)

Anterior Interdental gingiva vs posterior shape

Anterior: Pyramidal Posterior: Flattened

Hemidesmosomes in IBL

Attach JE cells to the tooth Transmit signals Regulate Gene expression, cell growth and differentiation

Physical function of periodontal ligament

1. Protects from injury 2. Transmits occlusal forces to bone 3. Attatches teeth to bone 4. Maintains gingival tissues in their proper place 5. Shock absorption

Interdental Gingiva shape determined by

Contact between teeth Width of approximating tooth surfaces Course of CEJ

Cementum thickness

Continuous deposition throughout life Thicker on distal surface than in mesial surfaces Thickest in apical third and functional area

Sulcular fluid (GCF) composition

Enzymes Proteins Antibodies Cellular elements

Epithelial rests of Malassez

Epithelial cell groups in periodontal ligament after disintegration of Hertwig's epithelial root sheath. Form periapical cysts and lateral root cysts

Horizontal fibers

Extend at right angle from cementum to alveolar bone

Transseptal fibers

Extend interproximally over alvolar bone crest. No osseous attachment.

Interradicular fibers

Fan from cementum to tooth in furcation area of multirooted teeth

Sulcular fluid (gingival crevicular fluid/GCF)

Inflammatory exudate In healthy gingiva -> no fluid Inflamed gingiva -> fluid present

Fenestration

Isolated area where root is covered only by periosteum

Less abundant cell types of gingival epithelium

Langerhans cells Melanocytes Merkel cells

Oblique fibers

Largest PDL fiber group Extend from cementum coronally obliquely to bone

Fibroblasts

Most common cell in periodontal ligament Stellate shaped Synthesize collagen Can phagosytose old cells

Marginal (free) gingiva

Most coronal part of gingiva that surrounds tooth. Not directly attached to tooth surface.

Sulcular gingival epithelium

Nonkeratinized Lines gingival sulcus, Lacks granulosum and corneum strata Contains K4 and K13 Lower enzymatic activity compared to outer epithelium

Three types of Cemetoenamel Junction

OMG Overlap 60-65% Meet 30% Gap 5-10%

Cementoblasts

Observed during active cementum deposition Oval/Cuboidal in shape

Outer gingival Epithelium

Parakeratinized 0.2-0.3mm thick Covers outer surface of marginal and attached gingiva High enzymatic activity

Alveolar process

Portion of bone that supports the tooth sockets

Attached gingiva

Portion of gingiva that is tightly bound to underlying tooth. Serves as barrier to bacteria. Runs from free gingival groove to mucogingival junction.

Interdental Gingiva

Portion of gingiva that occupies the interdental area.

Tensional Theory of tooth support

Principal fibers bear major responsibility in supporting tooth. When force is applied to crown, principal fibers unfold and straighten. Causes an elastic deformation of the bony socket.

Cancellous bone

Trabeculae enclosing irregularly shaped marrow space. Found in interradicular and interdental space More cancellous bone in maxilla than mandible

Osteoblasts

Uninucleated Cuboidal Synthesize bone Synthesize alkaline phosphate

Junctional epithelium turn over rate

Very fast, 2x faster than gingival epithelium

Alveolar Crest fibers

extend obliquely from cementum just beneath the junctional epithelium to alveolar crest *prevent the extrusion of the tooth and resist lateral tooth movements