19 - Pulp Biology, Liners, and Bases Flashcards
main functions of the pulp
- create dentin
- nutrition
- keep dentin layer HEALTHY by providing MOISTURE and essential NUTRIENTS
what nutrients do the pulp provide to dentin
albumin and fibrinogen
what are the 3 general types of pulpal cells
- formative
- defense
- reserve
what are the formative pulpal cells
odontoblast and fibroblasts
what cell:
Primary function is secretion of dentin during dentinogenesis.
Tooth development and the mature tooth
odontoblast
what cell:
the most abundant cell type in the dental pulp, aids in wound healing following pulp exposure.
Abundant in cell rich zone
fibroblasts
what cell:
Express all complement proteins, including the membrane attack
complex (MAC), allowing the lysis of cariogenic bacteria.
fibroblast
what are the defense cells
macrophages, histiocytes, and lymphocytes
what cells are undiferentiated mesenchymal cells that can develop into odontoblasts and/or fibroblasts
reserve
what are important regions during dentinogenesis
pre dentin and mature dentin
what is D, P, and arrows?
D = mature dentin
P = pre dentin
arrows = cell bodies of odontoblasts found at edge of pulp in columnar arragement
what are the layers of the pulp
how many levels of pulpal response
3!
what level of pulpal response:
Tubular sclerosis with formation of peritubular dentin
Tertiary dentine is focally secreted by odontoblasts positioned
beneath injured dentine tubules or a pulp exposure in
response to primary and secondary dentine injury.
Level 1
what level of pulpal response:
odontoblastic process and/or cell body death
level 2
what level of pulpal response:
inflammation and necrosis
level 3
what level has sclerotis dentin
level 1 pulpal response
what level of pulpal response:
- dentinal tubules become sclerosed and filled w/ peritubular dentin
- in response to slowly advancing irritant
- narrows lumen of tubule to decrease dentin permeability
level 1
what is a slowly formed dentin that constrict dimensions of PULP CHAMBER? does this continue thru life?
Secondary dentin - YES!
what level:
Death of odontoblastic process
Eventually, death of cell body
Response to intermediate stimulus
level 2 pulpal response
level 2 pulpal response can lead to differentiation of new odontoblasts producing what
reparative dentin on pulpal wall = tertiary dentin
if only odontoblastic process dies, an empty dentinal tubule is left called what
dead tract
what are types of reactionary dentin
- tertiary
- reparative
Tertiary Dentin caused by externalstimulus, reactivates the dentinogenic activity of ___.
pre-existing odontoblasts
what functions as a biological seal stimulated by CaOH
reparative dentin
tertiary dentin is generated by what cells?
osteoblast like replacement cells (odontoblast is dead)
what pulpal response:
Pulpal inflammation and DEATH in
response to severe irritation
level 3
what pulpal response:
Due to acute caries, careless preparation or
improper material selection
The pulpal response can change from
reversible to irreversible as a result of
bacterial invasion or trauma
level 3 pulpal response
factors the influence level of response
- intensity of stimulus
- adequacy of pulpal blood supply
- cumulative effect of previous injuries
effects of aging on pulp
- Increased fibrosis and decreased cellularity
- Decreased circulation
- Lesser capability to repair
- Pulps of young teeth more susceptible to injury from cavity preparation because they are larger
pulps of [older or younger] people are more susceptible to injury from cavity preparation because they are larger. they are [more or less] likely to recover
young; more
hydrodynamic theory of pain contends that many pulpal response are result of what
dentinal tubular flow
what are certain treatments that occlude tubules that should prevent fluid flow and reduce pain? how does it do this
fluoride - reacts with Ca in dentinal fluid to form CaF
what triggers a pulpal response
stimulus
what are examples of pulpal injury caused by dentinst
Local Anesthesia
Frictional Heat
Light Curing Units
Dentin Desiccation (dehydration)
Exposure to Toxic Materials
Bacterial Contamination
how can you generate heat during cavity preparation
- rotational speed
- pressure exerted
- area of surface contact by instrument
how heat is generated w/ rotational speed
higher rpm = more heat
how heat is generated w/ pressure exursion
more force = more heat
w/ electric handpieces you get more torque (won’t stall out) so you can exert more force
how does the area of surface contact by instrument generate heat
larger burs = more heat, due to greater surface contact
elevating pulpal temperature by what temp can cause coagulation necrosis
10 C
steps to avoid head generation during cavity prep
Use Sharp Burs
Use Intermittent Pressure
Use a Coolant
what is the 3 coolant system (what is most effective and least effective)
Air/water - most effective
Water
Air- least effective
how can dentin by dehydrated
heat build up or over drying
T/F: tissue fluid from tubule creeps toward the dry surface because of capillary action
true
can pulpal tissue tolerate minor amounts of dehydration
YES
what happens during dehydration
a strong capillary actionaspirates the odontoblastic cell body into the tubule
once the cell body is aspirated into the tubule, what happens to the odontoblast
DIES
Death followed by decomposition with infiltration of the pulp with cellular breakdown products produces ___
inflammation
after dehydration, healthy pulp may recober by generating what odontoblasts
seocndary odontoblasts to produce reparative dentin
what pulp may not recover after dehydration
non-healthy pulp or aging pulp
what is the goal of proteting pulp
protect from unwanted side effects of restorative material and restorative process
what do we need to protect the dental pulp from
- acidity of certain materials (zinc phosphate cement)
- thermal conductivity of certain materials (amalgam and gold)
what are toxic chemical materials in dentistry
primarily acidic materials: ZnPhos, GIC, resins
what are types of chemical damage
- direct damage
- indirect damage
what is direct chemical damage
material itself causes damage
what is indirect chemical damage
- Material does not cause damage, but alters conditions SO that some other factor can cause damage
- Bacterial leakage and contamination
are dentinst capable of stimulating pulpal injury thru bacterial contaimination
yes
what are sources of bacteria causing pulpal injury
Microleakage
Incomplete caries removal
Poor field isolation (Saliva)
what is one of the only restorative materials capable of chemically bonding to tooth structure
glass ionomer
what is microleakage
fluid, debris, micro-organisms can seep into the tooth-restoration interface
Seepage = microleakage
is there adhesion beteween amalgam and tooth structure
no
what are potential causes of gap formation in amalgam
- NO adhesion between amalgam and tooth structure
- Differences in coefficients of thermal expansion- amalgam vs tooth structure
- Dimensional changes during the setting reaction
- Inadequate condensation - NO MATTER HOW HARD YOU CONDENSE
- Trituration time Excessive contraction with excessive trituration
- Improper insertion and condensation
- Alloy particles
what is the primary corrosion product in aged amalgam
silver sulfide
what is the potential cause of leakage in composite
- Lack of adhesion between composite and tooth structure
- Dimensional changes during the setting reaction
- Curing shrinkage
- Bulk fill
- Improper insertion
- Saliva contamination
what is the most corrosive phase in corrision
The copper-tin phase which replaces the gamma-2 phase is the most corrosive.
A high-copper corrosion-resistant amalgam with a small initial gap can seal as rapidly as a _____
traditional low-copper corrosion-prone amalgam with a high initial gap.
in a low-copper amalgam system, the most corrodible phase is what
tin-mercury (gamma-2) phase
Burnishing the amalgam toward the
cavosurface has been shown to [enhanve or reduce] the EARLY microleakage associated with SA
REDUCE
T/F: Studies show that double burnishing, pre- carve and post-carve is LESS effective than either one alone in reducing microleakage
FALSE! MORE EFFECTIVE!
T/F: Evidence suggest that properly placed composites placed with proper application of adhesive, incrementally place to minimize stress at the cavo surface margin perform well with respect to leakage at the margins. Margins in dentine generated less reliable resistance to leakage.
true
the combined ionomer-composite restorationop rovides what
- chemical bond to dentin
- micromechanical bonding of composite to ionomer surface
- acceptable esthetic result
can heat and cold be transmitted toward the pulp thru metallic restorations
YES
thermal diffusion thru material is a function of what parameters
- thermal conductivity of material
- thickness of material
what are poor thermal condutors?
dentin and composites
what thickness of dentin will minimize effects of microleakage
2.0 mm dentin
as dentin thickness [increases or decreaess] the severity of microleakage decreases
INCREASES
what is the single most important factors in protecting the pulp
remaining dentin thickness
what are the indications for the use of intermediary materials
- Pulpal repair
- Prevention of toxic effects of materials- acid etching
- Thermal protection
- Electrical protection (Galvanic shock)
- Foundation to condense against
- Esthetics
- “Block out” of undercuts/indirect restorations
what is a liquid primer like material that seals dentin surface prior to placing definitive restorative materials
cavity sealer
what are current products used as cavity sealers? what are they used under
used under silver amalgam:
Gluma Desensitizer and G5 desensitizer
what do sealers contain that are effective sealing agents for dentin
HEMA and glutaraldehyde
examples of sealer products
Prime & Bond NT (used at CU)
Optibond
Scotchbond
Singlebond
Gluma
G5
order of sealers, bases and liners from thinnest to thickest
sealer -> liner -> base
what is usually a liner
CaOH or glass ionomer product
what is applied in htin layer 0.5 mm and is a protective barrier between dentin and restorative material
liner
what is:
Compatible with all restorative materials
Chemically bond to dentin (close adaptation)
Good thermal insulation
Light cured
Impregnated with CAOH
dimethacrylate liners
what are dimethacrylate liners impregnated with
CaOH
why does CaOH have a high pH (9-14) alkaline environment
Antibacterial
Promotes Odontoblastic Activity
Promote Sclerosis
o Reduce permeability
CaOH must contact what or be within ___mm to be effective
contact pulp or within 1 mm
if CaOH directly contacts to pulp what happens
leads to irritation and stimulates production of secondary dentin
only direct pulp cap what tooth
asymptomatic tooth with no evidence of PA pathology
how to apply CaOH to pulpal exposure? what is the best way
application instruments, perio probe, or directly out of syringe with clean tip (but flows too rapidly)
PERIO PROBE IS BEST WAY
what is a substance under a resotration that:
blocks out undercuts in the preparation,
acts as a thermal or chemical barrier to the pulp,
controls the thickness of the overlying restoration
base
what is the thickness of base
usually any thickness but usually 2 mm
what are examples of bases
- ZOE /IRM-not used much anymore
- ZnPhosphate Cement
- Glass lonomers: Fuji IX sets in 3 min 35 sec, Fuji II LC (light cure), Vitrebond - light cured
- Ultrablend or Vitrebond (can be used as a liner or a base)
what material is this:
A Bioactive liner and pulp capping material
Compatible with all restorative materials
Chemically bond to dentin ???
Good thermal insulation
VLC cure (light cured) Radiopaque
Impregnated with CAOH
dimethacrylate liner/base ultrablend
what material is this:
INTRODUCED TO PROFESSION IN 1970s
Favorable properties
Biocompatibility
Chemical Adhesion
Fluoride release
Bonds to dentine- chemical
Hydroxyl ions chelate with Calcium
glass ionomer cements glass polyalkenoate
what are the liquid and powder composition of glass ionomer
liquid = polyacrylic acid
powder = aluminosilicate class
what part of glass ionomer provides chemical bond to clacium of denitn which results in chemical bond to tooth structure and bonds to first calcium ion it contacts
polyacrylic acid (liquid)
what part of glass ionomer releases fluoride
alumino-silicate glass (powder)
for glass ionomer to be “TRUE”, the constituents when mixed must result in what? not what?
must eraults in acid-base reaction (not light cure)
when to use cavity conditioner
when glass ionomer used as permanent restoration
how long do you scrub cavity conditioner with cotton pellet into prep
20 seconds
what is a mild polyacrylic acid solution that removes smear layer and acquired pellicle
cavity conditioner
what increases bond strength between glass ionomer and tooth structure
cavity conditioner
what is this:
1-2microns thick
Surface accumulation of debris
Organic and inorganic components
Dentine chips
Odontoblastic remnants
smear layer
what is this:
A glycoprotein film
High in Calcium ions
From saliva
Forms on the surface of enamel and dentin in seconds
It forms Does NOT rinse off
dental pellicle or acquired pellicle
the surface of enamel and dentin attract what the creates the pellicle layer
salivary glycoproteins and bacterial products
how to use dentin conditioner
Use on all dentin to be covered
Pre-treat with polyacrylic acid conditioner.
Significantly increases the ionic bond to dentin.
Removes the acquired pellicle and smear layer. Or will bond to PELLICLE.
Use a small cotton pellet to scrub the surface of the tooth.
advantages of GI bases
- Fluoride Release
- Minimal Solubility
- Bond to Tooth Structure (lonic Bonding to Calcium and Phosphate, Chemical bond to dentin through attachment to calcium
carboxyl group to Ca+) - Good Strength (Can condense SA against it)
- Radio-opaque
advantages of GI
- biocompatible (must have 1 mm of dentin between GI and pulp)
- reduces post-op sensitivity with resins (no gap beneath restoration and tooth, no gap = no flexion = no pumping of tubular fluid)
disadvantages of GI
extreme moisture sensitivity!!!
- If water absorbed during initial set, becomes chalky and soft (autocure)
- If dehydrate, crack and craze (both autocure and VLC)
- Short working time (autocure)
- Does not stimulate pulpal repair
what is a composite material consisting of cermaic and metallic materials
CERMET
what is this:
- glass ionomer cement with 100% fine
silver alloy powder - has high temperature resistance and
hardness - metal has the ability to undergo plastic
deformation. - High Radiopacity and strong color contrast
- releases Fluoride
CERMET
what material:
Releases Fluoride
Bonds with calcium
- Will bond to Acquired Pellicle
- Remove Acquired Pellicle prior to cementation
Low solubility
crown cementation - resin modified glass ionomer cement
