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117 Cards in this Set

  • Front
  • Back
Enamel (general characteristics)
Hardest, most durable tissue. 96% inorganic, 1% organic, 3% water. Calcified hydroxyapatite makes up 65% inorganic, rest is carbonate, magnesium, potassium, sodium, fluoride.
Enamel (general)
avascular, no living cells. No additional enamel formed. REE adheres and forms cuticle (Nasmyth’s Membrane), which can be calcified and cause intrinsic staining.
Enamel color
variety of shades of bluish white (translucent). Most clear at incisal edge. Deciduous teeth are more opaque white
Tome’s processes
form enamel matrix at incisal edge and progress cervically.
Enamel apposition
at formation, mostly organic, then as tome’s processes secrete matrix, rest of ameloblast pumps hydroxyapatite into forming enamel, which begins mineralization.
Enamel mineralization
occurs from the inside-out, mineralized first by DEJ. Ameloblasts continue to pump calcium hydroxyapatite as it withdraws from organic matrix. When ameloblasts done with enamel, they lay down cuticle and become part of REE.
Enamel rods
structural units. Extend entire length from DEJ to surface. Roughly perpendicular to DEJ, but some curvature. Key-hole shaped (interlocking adds strength)
Interprismatic region (interrod)
forms outer portion of enamel rod, between individual enamel rods. Matrix is less mineralized and different crystal orientation
DEJ is scalloped
(concave toward enamel) for strength.
Lines of Retzius
growth lines. Appear as cross striations (like concentric tree rings). Help form perikymata and imbrication lines. Caused by alteration in enamel formation (trauma, disease, high fever)
Neonatal line
formed by traumatic event of birth.
Primary teeth and 1st perm. Molars
Enamel spindles
projections of dentinal tubules that cross DEJ before mineralized (usually cusps or incisal edge)
Enamel tufts
brush-like formed by abnormal crystallized enamel. By DEJ
Enamel Lamallae
partially calcified vertical faults from DEJ to surface (usually cervical enamel)
Caries progress more rapidly in ___
enamel tufts and enamel lamella because less mineralized
Gnarled enamel
very tough, wave-like.
Enamel destroyed by __
odontoclasts (shedding teeth). Not destroyed under normal processes. Enamel repair only through remineralization.
Enamel etching
interrod is partially dissolved, so dental materials bond better (sealant, composite)
Changes to enamel with age (normal)
attrition (can force formation of secondary dentin), decreased permeability,
increased fluoride content (less permeable and more fluoride mean stronger).
More decay on __ area in older patients
cervical (Class V)
Caries penetration of enamel
once through enamel, caries spread laterally into dentin. Enamel can break because dentin support is lost.
Fluoride
systemic (fluorosis ); topical
Dentin (general characteristics)
second hardest tissue. 70% inorganic (20% organic, 10% water).
Dentin covered by enamel or cementum. Makes up bulk of tooth. Contains NO cells, but does have cellular extensions of odontoblasts
Dentin color
yellowish. Gives teeth color.
Can be stained if exposed.
Very porous (smokers, coffee, etc)
Odontoblastic processes
cellular extensions of odontoblasts up the dentin toward CEJ
Exposure of dentin in oral cavity
abnormal
Deninogenisis
process of predentin formation. Continues through life as long as odontoblasts are vital
Predentin
laid down by odontoblasts (outer cells of dental papilla). Layer of non-mineralized dentin remains and lines outer pupal wall
Maturation of dentin
Primary: crystals form globules in collagen fibers. Secondary: strengthens crystal
Globular dentin
primary & secondary mineralization, complete fusion
Interglobular dentin
only primary mineralization has occurred, and not fuse completely. Slightly less mineralized. Near DEJ
Dentinal tubules
“holes” in the dentin; extend from pulp wall to DEJ/DCJ. Contain odontoblastic processes and afferent sensory axon (PAIN only stimulus). New teeth: process extends all the way. With age, it draws closer to pulp (decreased sensitivity, caries progression down tubule)
Hydrodynamic hypersensitivity theory
plug holes in dentin so fluid doesn’t move = no pain
Types of dentin (by mineralization)
peritubular: walls of dentin tublues. Most mineralized. Intertubular: between tubules, less mineralized.
Types of dentin (by location)
Mantle: outer layer; 1st formed. More mineralized. Circumpupal: bulk of dentin, less mineralized. Pre-dentin: unmineralized found in new teeth next to pulp
Types of dentin (by chronology)
Primary: formed before apical foramen closes. Secondary: formed after apical foramen closes (made throughout life). Tertiary: reparative; rapid resonse to injury; from pulp outward, more irregular tubules. Sclerotic: when odontoblastic processes withdraw, tubules fill with calcium salts (complete mineralization, sealed)
Lines of Von Ebner
imbrication lines. incremental growth lines. run perpendiular to dentinal dubules seen under high magnification.
contour lines of Owen
disturbances in formation of dentin. formed when Von Ebner form very close together. seen under lower magnification.
Neonatal line
pronounced contour line from trauma of birth
Tome's Granular layer
small, unmineralized areas of dentin, forms a band just under cementum ONLY on root surfaces. If exposed, it's sensitive to hot, cold, sweets
dental pulp (general)
only NON-mineralized tissue in tooth, contains odontoblasts in outer layer, rest is made up of CT and fibers (fibroblasts). Blood, nerves, and lymph enter through apical foramen.
Functions of pulp
formative: by odontoblasts. sensory: any stimulation is felt as PAIN. other sensations due to PDL. Nutritive: nutrition to odontoblasts, which extend to dentin. Defensive: WBCs used as inflammatory response. Only place to swell is at apical foramen. production of secondary, reparative, and sclerotic dentin.
Odontoblasts
found next to dentin. CANNOT reproduce after differentiation.
Fibroblasts
Form collagen fibers; most numerous cells in pulp. With age, number decreases while the number of fibers increase.
Undifferentiated mesenchymal cells
Differentiate into different kinds of cells depending on demand.
Defensive cells
rid body of dead bacterial cells. Macrophages engulf particles and destroy them. B-lymphocytes (purpose unknown).
Also present in pulp
Blood and lymphatic (number decreases with age). Nerves (enter through apical foramen) form a dense network; nerve cell bodies in odontoblast cell layer interspersed between cells
odontoblastic layer (cell zones/layers)
outermost layer next to dentin. Cell bodies of afferent axons are located between odontoblasts.
cell free layer (cell zones/layers)
appears empty, however contains numerous nerves and blood vessels
cell rich layer (cell zones/layers)
extensive vascular system with many cells. primary cell is fibroblast.
pulpal core (cell zones/layers)
except for location, very similar to cell-rich zone.
accessory canals
extra openings on sides of root that connect pulp to PDL. May contain blood, nerves, lymph. More common in molars.
pulp stones (denticles)
calcified masses of dentin found in pulp; usually irregular; can be seen on x-rays. Grow larger with age, can form around blood clots, dead cells, collagen. Defense mechanism. If large, can interfere with RC treatment.
Pulp Changes with Age
number of cells decreases, number of blood and lymph decreases, pulp size decreases, number of fibers INCREASES (becomes fibrotic)
Dentin Changes with Age
tubules narrow, odontoblastic processes retract (less sensitivity)
Periodontium
Supporting soft and hard tissues that maintain teeth in a functional state. Made up of cementum, alveolar bone, periodontal ligament, gingiva.
Cementum (general characteristics)
covers anatomical root (tome's granular layer dentin). attachment point to fibers of PDL make surface rough (bacteria/calculus attach well, same susceptibility to decay as dentin
Cementum (general)
similar hardness to bone; 65% inorganic, 25% organic, 12% water. pale yellow (lighter than dentin). Avascular, no innervation. thinner cervically; thicker apically
acellular cementum
no cells w/in it, no embedded cementocytes. Cementocytes that form it are found in PDL (forms slowly). Cervical 2/3 of root, very thin layer covers entire root (first layer deposited)
Cellular cementum
contains cells, cementocytes within, apical 1/3 of root and interradicular. Layers can be added over time
Development of cementum
develops from dental sac (mesenchyme) after Hertwigs root sheath disintegrates.
Cementogenisis: Cementoblasts lay down cementoid. Matrix is calcified, trapped cementoblasts become cementocytes.
Surface of cementum
projections on surface will attach to PDL fibers (Sharpey’s fibers while they are in cementum). Only in cellular cementum, also extensions of canaliculi that connect to PDL.
CEJ relationship between Cementum, Enamel
overlapping (60%)
end to end (30%)
gap (10%)
Cementum repair
less readily absorbed than bone. Do not continuously repair, only as result of trauma
Acellular cementum
primary cementum. First layer deposited on DCJ on entire root. NO embedded cementocytes. Near CEJ, cervical 1/3
Cellular cementum
mainly apical 1/3 and in between roots (interradicular). Form faster, so cementocytes become trapped (surrounded by lacunae).
Lacunae
cementocytes surrounded by it (similar to bone)
Canaliculi
canals radiating from lacunae. Most radiate towards PDL. Nutrient canals to receive nutrients and take waste.
Cementocytes location
randomly in cellular cementum, but increase closest to PDL.
Cementoblasts
located in adjacent PDL, which makes repair (cementogenesis) possible
Clinical importance cementum
can be formed continuously, and can be repaired. ONLY remodeled when damaged.
Hypercementosis
(cemental dysplasia) excessive formation in apical 1/3. Caused by trauma. Tooth difficult to extract.
Ankylosis
excessive cementum fills PDL, fuses tooth to bone. Very rare, extraction very hard.
Cementicles
small bodies of cementum found within PDL or surface of cementum. No clinical significance.
Cemental spurs
found at or near CEJ, not easily removed.
Relationship of cementum to calculus
when cementum is exposed, plaque and calculus attach to rough places fibers had inserted.
Cementoossifying firbroma
neoplasm, causes enlarged bony growths
Alveolar bone
(alveolar process or alveolar ridge) contains roots of teeth; divided by location (alveolar bone proper, supporting alveolar bone, combination)
Alveolar bone proper
(cribriform plate or lamina dura) lines tooth socket (compact bone) contains Volkmann’s canals. Sharpy’s fibers inset into this bone. Dense radiopaque line
Alveolar crest
most cervical rim. In health, 1-2 mm apical to CEJ
Supporting alveolar bone
cortical bone (compact bone on facial and lingual). BASE Trabecular bone: cancellous bone between alveolus and cortical plates. Spongy.
Combination of alveolar and supporting
interdental septum. Bone between adjacent teeth. Both compact bone and trabecular supporting bone
Intraradicular septum
bone between roots. Compact and trabecular supporting bone.
Basal bone
forms the body of the maxilla and mandible. More resistant to absorption.
Development of jaw bones
from first branchial arch. Begins as intramembranous ossification. Serves as a template. Fuses around nerves (forming canals)
Clinical considerations Alveolar Bone
pressure leads to resorption tension/pulling causes deposition
Endentulous
lose vertical dimension
Implants
osseous integration (fuses to bone). No PDL
Bone Loss
first becomes apparent in alveolar crest and interdental septum (looks fuzzy)
Periodontal ligament (general)
occupies space between teeth and bone. Support and maintain teeth. Prevent direct contact of tooth with bone. Shock absorber. Continuously remodel bone. X-rays radiolucent.
Widened PDL
abnormal increase in function
Periodontal atrophy
PDL not stimulated and shrinks
Apical foramen
blood and nerve supply enter the tooth. Carries nutrients.
Sensory
pain, pressure, temperature, proprioception, percussion
Periodontal ligament developed from
dental sac (also cementum and alveolar bone)
Components of PDL
fibers, ground substance, fluid, blood vessels/nerves, cells (fibroblasts, cementoblasts, osteocytes, osteoclasts, osteoblasts, donotoclasts, undifferentiated mesencymal, epithelial rests)
Fibers of PDL
formed by fibroblasts, made of collagen, called Sharpey’s fibers (when embedded in cementum and bone)
Orientation of PDL fibers
Functional tooth: fibers straight and arranged in groups. Non-functional (perio atrophy): fibers relaxed and wavy, and if placed in function again will be painful and sensitive until PDL and bone repair
Alveodental ligament
grouped based on orientation to tooth and related function. Resist rotational/twisting forces. When embedded in cementum or bone called Sharpey’s fibers.
Alveolar crest group
connect crest to cervical cementum. Resist tilting, rotation, intrusive/extrusive
Horizontal group
root to bone horizontally, apical to alveolar crest group. Small group. Resist tilting/rotational
Oblique group
diagonal. Apically from bone to cementum. Most numerous. Cover apical 2/3. Resist intrusive. Without them, constant pressure would cause resorption.
Apical group
located around apex. Resist extrusive
Interradicular group
ONLY between multi-rooted teeth. Cementum of root to cementum of other root (NO bone contact). Resist intrusive/extrusive and tilting forces.
Interdental ligament
(transseptal ligament) connects adjacent teeth. Coronal to alveolar crest (cementum to cementum). Maintain proximal contact, resist rotation
Gingival fiber group
(dentogingival ligament) supports gingiva. Circular, dentogingival, alveolar, dentoperiosteal, periosteal
Circular fiber
encircle tooth. DON’T touch tooth, like rubberband. Inflammation causes them to be loosened
Dentogingival group
connects marginal gingiva to coronal cementum. Keeps tissue close to tooth
Alveolargingival fibers
alveolar crest to marginal gingiva. Keeps gingiva attached to bone
Dentoperiostal fibers
cementum to alveolar crest. Protect PDL. attach tooth to bone
Periosteal gingiva
facial of alveolar crest toward gingiva. Help stippling
Components of PDL
many blood vessels in loose CT.
3 main sources: bottom of alveolar socket, alveolar crest, cribriform plate.
Vessels from network around root with anastomes (connections)
Epithelial rests of Malassez
remnants of epithelial root sheath
Cementicles
very small spherical calcified bodies of stray cementoblasts in PDL
Clinical considerations PDL
occlusal trauma causes widening of PDL (seen on x-ray between lamina dura and cementum)
Periodontal disease targets
soft CT fiber groups. Can’t be regenerated. Requires surgery
Lack of use
PDL atrophies, narrows PDL space