Perio Exam 1 (third set of lectures)

D1 Fall

pale/ salmon/ coral pink

healthy gingiva

healthy gingiva

knife-edge/ scallop, firm, stippling

marginal gingiva (free)

portion of gingiva that borders the teeth, movable

attached gingiva

firm, immobile tissue that covers the roots of teeth and extends from gingival margin to the mucogingival junction 

interdental papilla

gum tissue that fills the spaces between adjacent teeth

Periodontal ligament

connects tooth to alveolar bone

widest at apex and cervix (hour-glass shaped) 0.1-0.25mm

PDL space

PDL physical function

resistance to impact of occlusal force, transmission of occlusal force to bone

PDL formative and remodeling function

formation and resorption of bone and cementum

PDL nutritional function 

via blood vessels; lymphatic drainage

PDL sensory function

transmitting tactile, pressure, and pain

missing around implants

PDL

Cementum

covers root surface, fibers of PDL attached 

can be seen in X-ray

periodontal ligament

cannot be seen in X-ray

cementum

thickest at Apex, thinnest at CEJ; thins as a person ages

Cementum

Alveolar Bone

housing for the roots of the teeth 

part of the maxilla and the mandible, dependent on the presence of teeth

alveolar processes

follow the root

shape of the alveoli (socket)

alveolar bone structure: alveolar bone proper (Lamina dura)

cribriform plate

alveolar bone structure: trabecular bone

supporting alveolar bone

alveolar bone structure: compact bone

formed by haversian bone and bone lamellae

vascular supply of periodontium: maxillary

anterior superior alveolar artery (ASA), posterior superior alveolar artery (PSA), infraorbital artery, greater palatine artery

vascular supply of periodontium: mandibular

inferior alveolar artery and branches (IA)

blood supply for periodontium

interseptal artery, dental artery, alveolar artery, PDL vessels, Supraperiosteal vessels, Interseptal artery

Submandibular lymph nodes EXCEPT

upper deep cervical LN, jugulodigastric LN (largest), palatal gingiva

innervation of periodontium

trigeminal nerve (V), autonamic nerve

trigeminal nerve responsible for

pressure, touch, temperature, pain, proprioception from PDL (tooth position, movement, thickness between teeth in occlusion)

autonomic nerve is responsible for

superior cervical ganglion

gingival epithelium: keratinocytes (main)

producing tonofilaments, soft tissue renewal

gingival epithelium: non-keratinocytes

Langerhans cells (anti-presenting cells), Merkel cells (tactile preceptors), melanocytes

NO Stratum Corneum, NO Stratum Granulosum

NON-keratinized

cell nuclei in Stratum Corneum, NO Stratum Granulosum

PARA-keratinized

NO cell nuclei in Stratum Corneum

ORTHO-keratinized 

Ortho-K completed (NO Nuclei)

Stratum Corneum, Stratum Granulosum, Stratum Spinosum, Stratum Basale

Para-K intermediate (Nuclei)

Stratum Corneum, Stratum Spinosum, Stratum Basale

Non-K

Stratum Spinosum, Stratum Basale

gingival epithelium - tissue renewal

cell slough away, cell degeneration (degenerate into Stratum Corneum), lose organelle (for protein synthesis and energy production), produce increased protein, cell loses ability to divide

epithelial turnover time

10 days

cell degeneration

surface sloughing of mature keratinocytes

mitotic division of keratinocytes occurs at

basal cell layer

oral epithelium

faces the oral cavity, extends from gingival margin to muco-gingival junction (MGJ)

oral epithelium cells - keratinocytes

keratin filaments, surface sloughing, basal cell renewal, terminal differentiation, controlled by connective tissue

sulcular epithelium

extends from oral epithelium into sulcus

NO stratum corneum or stratum granulosum (non-keratinized)

sulcular epithelium

junctional epithelium

attaches gingival epithelium to tooth, important in disease and health, less adhesions between cells, allows fluids to pass

features of junctional epithelium

two layers of basal lamina: external (w/ connective tissue) and internal (firmly attachment to the tooth)

barrier against plaque, highly permeable (gingival fluid, inflammatory cells, immunologic, host defense)

features of junctional epithelium

turnover rate of junctional epithelium

4-6 days

Oral Epi

crest, marginal gingiva, and AG; 0.2-0.4mm, k or para-k

Sulcular Epi

gingival sulcus, 0.5mm, non-k, susceptible to infection 

Junctional Epi

attach gingival epi to tooth, 5-30 cells in health, non-k, defensive to bacteria

connective tissue composition: connective tissue fibers

collagen fibers (60%) type I & IV, elastic fiber, reticular fiber

connective tissue composition: cells 

8%, fibroblasts (main) responsible for collagen synthesis and degradation regulation

connective tissue composition: ground substance

5%, between fibers and cells

epithelial - connective tissue interface

ensure sufficient adhesion, provide nutrition and waste disposal

Basal Lamina

Lamina lucida, Lamina Densa

Lamina lucida

40 nm, immediate beneath, basal cell membrane, proteoglycan laminin

Lamina Densa

immediate underneath lamina lucida, type IV collagen, connect to connective tissue

Collagen

a protein composed of different amino acids

function of collagen

framework maintenance, maintain the tissue

synthesized by fibroblasts, chondroblasts, osteoblasts, odontoblasts

collagen

type I collagen

most common

Gingiva - gingival fibers

a system of collagen fiber bundles, type I collagen fiber

Gingiva - gingival fibers

brace the marginal gingiva against the tooth, provide the rigidity for masticatory force, unite the free gingiva margin with cementum and AG

PDL Composition

collagen type I (80%) and type III, bundle of fibers

cellular element of PDL

fibroblasts (most common) regulate collagen turnover

cementum forming

cementoblasts

bone forming

osteoblasts

principle fibers of PDL

alveolar crest fibers, oblique fibers, transseptal fibers, horizontal fibers, interradicular, apical fibers 

alveolar crest fibers

prevent tooth extrusion, resist lateral tooth movement

oblique fibers

the largest group, bear and transform the brunt of vertical masticatory stresses

transseptal fibers

over the alveolar bone crest, no osseous attachment 

apical fibers

do not occur on incomplete formed roots

cover root surface, attaches PDL fibers to root, attachment of Sharpey’s fibers, similar to bone: laminated, no vascularization

CEMENTUM

cementum composition: inorganic content  

45-50%, mainly hydroxyapatite

cementum composition: organic content

type I collagen 90%, type III collagen 5%

cementum composition: non-collagenous component

proteoglycans, glycoproteins, phosphoproteins

cementum: acellular/ primary

cervical 1/3-1/2, formed BEFORE the tooth reaches the occlusal plane, more Sharpey’s fibers, MORE CALCIFIED, arranges in lamellae, separated by incremental line

cementum: cellular/ secondary

apical 2/3 - 1/2, formed AFTER the tooth reaches the occlusal plane, less Sharpey’s fiber, LESS CALCIFIED, arranges in lamellae, separated by incremental line

bone outer surface covered by 

periosteum

bone-forming

osteoblast

bone inner surface covered by

endosteum

bone composition: organic

1/3, collagen type I (90%)

bone composition: inorganic

2/3 mainly minerals calcium and phosphate, in the form of hydroxyapatite

bone-resorbing

osteoclast