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Aim of vital pulp therapy
stimulate formation of tertiary dentin (could be reparative or reactionary [surviving postmitotic OD])
Pulp vulnerable to injury because (3)?
1. large vol of tissue, small vol of blood
2. terminal circulation, limited collateral
3. low compliance
Describe the Kakehashi study?
Germ free rats w/ expose pulps, no inflammation but dentin bridge formation (32 days)
Reg rats partial necrosis (8 days) and complete in (14 days).
Two issues modify pulp healing...
1. duration of pulpal exposure
2. abilty of material to seal vs. toxicity (both found to be important)
Success of Ca(OH) pulp capping is reduced from ____ to _____ when microbial contamination is extended from _ hour(s) to _ days.
1971 Brannstrom and Nyborg findings?
microleakage is greatest threat to pulp
Pulpal devitalization following restorative procedure is likely to result from?
- 1. bacteria (main factor)
- 2. mechanical injury
- 3. depth of cavity
- 4. toxicity of materials
Pulpal mechanism to reduce bacterial invasion?
- 1. outward fluid flow
- 2. neutrophils
- 3. toxic substance sequester by binding to dentin
What did Bergenholtz review/find?
Thin wall of primary dentin often prevents effects of toxic materials and bacterial leakage
In regards to size of pulpal exposures, many dentists belive that...
pulp capping is most successful when exposure is less than 1mm in major dimension and patient is young
Contrary to what dentist believe to size of pulpal exposure, it has been found that with partial pulpotomies:
96% success rate with 31 month follow-up and exposures ranged from .5-4mm
Ca(OH) and macrophages?
inhibits funciton of and reduces inflammatory reaction
Need for hemorrhage control in pulp capping?
first invesitgated by Marzouk and Van Huysen in 1966,
inhibits wound healing
shown to be successful with saline, NaOCl, CHX
__% of pulps irrigated with NaOCl prior to adhesive placement showed normal soft tissue reorganization and dentin bridge.
Dentin bridge formation is found in __% to __% of teeth treated with various Ca(OH) formulas.
What is the reduction of pulp when CaOH is used to cap?
caustic pH causes up to .7mm reduction
still used because antimicrobial
Describe the SEM of dentin bridge formed by CaOH, layers?
Superficial layer: amorphous layer of tissue debris
Middle layer: coarse meshwork of fibrodentin (most mineralized layer)
Inner layer: osteodentin
A summary of several primate studies shows what defects in dentin bridge by CaOH?
Tunneling defects, in 90% of 192 dentin bridges, possible leakage route
For successful vital pulp therapy, the healing process must exhibit these 3
1. rapid formation of hard tissue
2. barrier formation against 2nd pulp infections
3. induction of hard tissue at material/pulp interface
Genes/expression of difference in healthy vs diseased pulp?
85 genes vs. 360
What signaling pathway controls fate of multipotent stem cells?
Notch: CaOH pulp cap in adult rats
Notch 2: inc in coronal odonto
Notch 3: inc in area of PV cells
CaOH placement inc these ECM proteins that help with cell adhesion.
Fibronectin and tenascin
Pulp cells synthesize this in response to minor temp change?
RMGI as pulp capping material?
Great in primates (2yr follow up) but not the same in human teeth
Why are dental adhesives not recommend for pulpcapping?
Persistent intense inflammation and foreign body reactions
Many of the resin components empolyed in etch-and-rinse and self etching dentin adhesives are __________?
Mineralized tissue extension from the exposure site into the body of pulp
Seen with MTA
Most efficient bioactive molecule that induces homogenous and well mineralized reparative dentin?
Bone sialoprotein BSP
What two major growth factors are implicated in OD activity?
TGF-B1 released from demineralized dentin
NGF released from pulp
Dental pulp repair by implantation of bioactive molecules implies a cascaed of four steps:
1. mod inf
2. commitment of adult reserve stem cells
3. prolif of stem cells
4. terminal diff of stem cell
1969 Keyes describes 3 factors essential to caries:
1. susceptible host
2. cariogenic bugs
3. suitable substrate
all work stimulaneously
Caries penetration rate of dentin?
1mm every 6 months
When bacterial penetration come within ___mm of the pulp or when the bacteria ____ previously formed ____ dentin, the degree of pulpal disease becomes _________.
Reason for abript change in .75mm of dentin?
Bacteria by-products can overhwhelm the pulp, if all caries are removed except for this superficial layer then the tooth will heal.
Success of resin comp indirect pulp cap is dependent on (2 factors):
1. abilty of pulp to respond to material
2. sealing ability (total etch and total seal)
What is the atraumatic restorative technique (ART)?
Caries is removed with hand instruments and restored with GI.
Similar to MMPs what has been found to degrade comp bonds in indirect pulp caps?
Describe stepwise excavation?
6 months after indirect pulp cap over affected dentin (carious) is verified having been arrested and any darker dentin removed and resealed.