ch 13 dentin & pulp

globular dentin

-appears lighter microscopically

-complete crystalline fusion where primary and secondary mineralization has occurred completely

interglobular dentin

-arc like areas are darker microscopically

-only primary mineralization has occurred

which has more compressive strength, enamel or dentin?

dentin

dentinogenesis

process of dentin matrix formation

what is the primary phase of dentin development?

calcium hydroxyapatite forms as globules in collagen fibers of predentin

what is the secondary phase of dentin development?

-formed later in new areas of mineralization occur as globules form in partially mineralized predentin

-new crystal formation are regularly layered on the initial crystals (they do not fuse completely)

dentinal tubules

long tubes in dentin that extend from DEJ in the crown area to outer wall of pulp

where is the dentinal tubules thinner and wider at?

thinner near DEJ, wider near pulp

components of dentin

-mature dentin

-dentinal tubules (primary or secondary curvature)

primary curvature

resembles a large S-shaped curve

secondary curvature

-consists of small, delicate curves

-reflects smaller daily changes in odontoblast direction during apposition

types of dentin by relationship to dentinal tubules

-peritubular dentin (intratubular)

-intertubular dentin

peritubular dentin

-creates wall of dentinal tubule

-highly mineralized after dentin maturation

intertubular dentin

-found between tubules

-less mineralized than peritubular

types of dentin by its relationship to enamel and pulp

-mantle dentin

-circumpulpal dentin

-primary dentin

-secondary dentin

-tertiary dentin

mantle dentin

-under crown

-first predentin that forms

shows difference in direction of mineralization

circumpulpal dentin

-roots only

-found deep to mantle dentin around outer wall of pulp

-makes up bulk of dentin

-matures after mantle dentin

primary dentin

-formed in tooth before completion of apical foramen

-characterized by its regular pattern of tubules

secondary dentin

-formed after completion of apical foramen and continues throughout life of tooth

tertiary dentin

-reparative dentin

-forms quickly in response to localized injury to the exposed dentin

(INJURY ONLY)

clinical considerations: resorption

-dentin is mostly stable during the life of the tooth

-idiopathic reasons in few cases causes internal or external resorption process

clinical considerations: dentinal caries

much more serious than resorption

clinical considerations: restorative treatment

-antisensitivity medications are placed in prep prior to placing restorative materials (barrier in tubules to pulpal nerve)

-smear layer: composed of dental biofilm debris that interferes with bonding of restorative material to dentin

clinical considerations: dentinal hypersensitivity

-caused as result of caries, cavity prep, gingival recession, or attrition that opens dentinal tubules

-sometimes enamel and cementum leavs a gap, exposing the dentin at CEJ

clinical considerations: hydrodynamic theory

hypersensitivity due to changes in dentinal fluid

clinical considerations: tooth whitening

-performed in office or take home

-can lead to dentinal hypersensitivity as whitening material seeps into tubules

clinical considerations: aging

-diameter of tubules narrow

-becomes more exposed as a result of attrition and gingival recession

imbrication lines of von ebner

-incremental lines or bands noted in dentin

-develop at 90 degrees to tubules

contour lines of owen

-number of adjoining parallel dark imbrication lines

-demonstrate a disturbance in body metabolism

tomes granular layer

found in peripheral part beneath the root’s cementum

clinical considerations: pulp stones aka denticles

-true pulp stones

-false pulp stones

-free pulp stones

-adherent pulp stones

-embedded

clinical considerations: pulpitis

inflammation of pulp when injured

hue of dentin

yellow hue in color to transparent enamel

coronal pulp

located in crown of tooth containing pulp horns

radicular pulp

located in root pulp containing openings from pulp through the cementum into surrounding PDL

apical foramen

largest opening at apex of tooth allowing arteries, nerves etc to enter and exit pulp

accessory canals

form when HERS encounters blood vessel during root formation

pulp zones

-odontoblastic layer

-cell free zone

-cell rich zone

-pulpal core

odontoblastic layer

-first layer where secondary and tertiary dentin is formed

-lines outer pulpal wall

cell-free zone

-inward from dentin and contains nerve and capillary plexus

-no secondary or tertiary dentin, but new dentin is encroaching

cell-rich zone

contains increased density of cells compared to cell-free zone with more extensive vascular supply

pulpal core

-center of pulp chamber and final zone of pulp

-contains many cels and extensive vascular supply

aging pulp

-receding pulp horns

-smaller pulp cavity

-less sensitivity

reversible pulpitis

-exhibits quick, sharp hypersensitive response to thermal stimulus

-subsides with removal of stimulus

irreversible pulpitis

indicated by lingering response to cold temperatures

necrotic pulp

indicated by asymptomatic, nonvital tooth that does not respond to any stimuli

endodontic therapy

-pulp dies, surgically removed and gutta percha is placed with pulp chamber

-tooth no longer vital

pink spot on tooth

resulting in loss of tooth structure, resorption