Pulps and Nerves Flashcards
What embryonic tissues are stimulated during Apexogenesis?
HERTWIGS ROOT SHEATH
The most important part of root development is Hertwig epithelial root sheath composed of inner and outer enamel epithelium.
(IEE and OEE)
This sheath influence the adjacent MESENCHYMAL calls to differentiate into ODONTOBLASTS.
It seems that infection and inflammation are the most important factors to stopping the proliferation activity of cells.
*For this reason in apexogenesis after decontamination of inflamed part of canal with a material such as Ca(OH)2 and bacteria-sealing, we observe continuing in root formation.
Activity of cementoblasts and other regenerative cells is influenced by growth factors such as:
- epidermal growth factor (EGF),
- transforming growth factor-β (TGF-β)
- insulin-like growth factors (IGFs)
IGFs are believed to behave as proliferative factors for PDL cells, epithelial cells of Hertwig’s root sheath, or cells of Malassez.
What is the difference between Apexogenesis and Apexification?
APEXIFICATION:
inducing a calcified BARRIER at the apex of a NONVITAL tooth with incomplete root formation.
APEXOGENESIS:
VITAL pulp therapy procedure performed to encourage physiological DEVELOPMENT and formation of the root end.
Most common effect of internal bleaching of Non-Vital teeth?
External root resorption
On average, 10% of the cases of internally bleached teeth showed external cervical resorption as a consequence. The hydrogen peroxide liberated during the internal tooth bleaching presents wide permeability in the dentine and gets out through the dentine gaps in the amelodentinal junction of all human teeth.
What is the LEAST effective pulpotomy treatment?
Calcium Hydroxide
CaOH
Solubility
In radiographic analysis, the MTA group had the highest success and the CaOH group had the lowest success rate.
MTA and CH stimulate dentin bridge formation probably because of their biocompatibility and alkalinity. However, the most important distinctive feature of MTA is its good sealing ability, and it shows no signs of solubility.
The solubility of CH may cause bacterial microleakage from the furcation or coronal restoration
What is Vitapex?
Vitapex® is a premixed calcium hydroxide paste containing iodoform used as a temporary or permanent root canal filling material after pulpectomy.
CaOH
- Excellent antibacterial and bacteriostatic properties
- Promotes apexification and apexogenesis
What are the indications for NON-vital pulp therapy? (Pulpectomy) on a Primary Tooth
Nonvital pulp treatment for primary teeth diagnosed with irreversible pulpitis or necrotic pulp.
Irreversible pulpitis (e.g., excessive hemorrhage that is not controlled with a damp cotton pellet applied for several minutes) or pulp necrosis (e.g., suppuration, purulence).
The roots should exhibit minimal or NO resorption.
Percussion Sensitivity
How does CaOH promote Tertiary Dentin?
Low grade irritation
What is a radiographic sign of a successful pulpectomy?
Bone fills and returns within 6 months.
Radiolucencies begin to resolve in 6 weeks
What pulp treatment material promotes regeneration?
MTA
What is the range of treatments to a pulp exposure SECONDARY to TRAUMA in terms of size?
Size of Pulp Exposure
- <1mm: Direct Pulp Cap (MTA, CaOH)
- 1-4: Cvek pulpotomy, (if clean and adequate stopping of hemmorage)
- 4+: Pulpotomy
What does Sodium Hypochlorite do?
NaOCL
NaOCL
Disinfects and Sterilizes
Most common side effect of Ferric Sulphate?
Internal Resorption
What is the FIRST reaction of the pulp to dental caries?
⬇️
- DECREASE ⬇️ Dentin permeability by production of Sclerotic Dentin.
SCLEROSIS of Dentin
- ⬆️ Increase the deposition of mineral crystals in intratubular Dentin
- Which narrows the Dentin Tubules
- Which decreases Dentin Permiability
What is the relationship between gutta percha and latex allergy?
Chemically, gutta-percha is a polyterpene, a polymer of isoprene, or polyisoprene.
The cis structure of polyisoprene is the common latex elastomer.
Gutta percha could trigger an allergic reaction, also, in patients with latex sensitivity. Since gutta percha is the only widely acceptable material*, special care should be taken to avoid its extrusion into the periapical tissues to prevent any possible allergic reactions.
What is the compressive strength of MTA?
Comparable to?
The compressive strength of set MTA is about 70 MPa, which equals IRM and super EBA, but is less than that of amalgam
The initial compressive strength following 24 hours is 40 MPa, which increases to 67.3 MPa after 21 days.
If an Alveolar fracture occurs Apically to a roof apex, would you expect pulp vitality?
Yes
What kind of cells are used for apexification?
Mesenchymal stem cell said
It appears that dental stem cells have the potential for continued cell division and regeneration to replace dental tissues lost through trauma or disease.
What causes sclerotic dentin?
What its appearance?
What happens histologically
Dentinal sclerosis/transparent dentin-sclerosis of primary dentin is REGRESSIVE alteration in tooth characterized by CALCIFICATION of dentinal tubules.
“Glassy Appearance”
Peritubular Dentin decreases in circumference
Odontoblastic Process within tubule may or may not get occluded
It can occur as a result of injury to dentin by CARIES or ABRASION, or as part of the normal AGING process.
What is the mechanism of action of Ferric Sulfate?
🔴🚢
Coagulation and Occluding vessels 🚢
Hemostatic agent
it seems that agglutination of blood proteins occurs due to the reaction of blood with ferric and sulfate ions in acidic pH. 🔴
What is the radiopaque component of MTA?
📻⚪️
Bismuth Oxide
📻⚪️
Bismuth oxide in contact with sodium hypochlorite exhibited a CHANGE in COLOR from light yellow to dark brown
What are the two type of fibers that innervate the pulp?
Two types of sensory fibers are present in the pulp:
- A fibers - Myelinated
The A fibres predominantly innervate the dentin and are subgrouped according to their diameter and conduction velocities
More Sensitive to Stimulation
Mediate acute, sharp pain and are excited by hydromechanical events in dentinal tubules such as drilling or air-drying.
- C fibers - Unmyelinated
The C fibres innervate the body of the pulp.
Mediate a dull, burning, and poorly located pain, and are activated only by stimuli reaching the pulp proper
Once activated, the pain initiated by C fibres can radiate throughout the face and jaws. C fibre pain is associated with tissue injury and is modulated by inflammatory mediators, vascular changes in blood volume and flow, and increases in pressure.
What does a Laser Doppler measure in Pulp testing?
LDF can reliably differentiate between healthy and non-vital teeth.
Extremely accurate in predicting revascularization
Monitors dynamic changes in pulpal blood FLOW in response to pressure changes and following administration of local anaesthesia.
Pulp testing on immature teeth with incomplete root development?
EPT vs Thermal
Erupting teeth show an increased threshold value to EPT or may give no response, even though their vitality is assured.
Sensitivity to electrical stimulation appears to be related to the stage of root development.
In contrast, thermal testing with carbon dioxide snow gave consistently positive responses irrespective of the stage of dental development.
Internal Resorption after a pulpotomy is an indication of what?
Irreversible Pulpitis
What forms the pulp?
Dental Papilla
“Pulpilla”
Cvek Pulpotomy indications
The partial pulpotomy for traumatic exposures is a procedure in which the inflamed pulp tissue beneath an exposure is removed to a depth of one to three millimeters or more to reach the deeper healthy tissue.
-in pulp exposures 4mm or less
***(AAPD- Neither time between the accident and treatment nor size of exposure is critical if the inflamed superficial pulp tissue is amputated to healthy pulp.)
- indicated in young permanent teeth where pulp is exposed by mechanical or bacterial means.
- preserving as much tissue where root closure is not completed.
Apply CaOH, then GI, then restoration
What is the best material for pulpotomy?
MTA (white colored)
Best material for Apexogenesis?
MTA
What are the properties of MTA?
Radioopaque
Tolerant to moisture
Biocompatible with periradicular tissues
Non cytotoxic, but antimicrobial to bacteria
Non-resorbable
Minimal leakage around the margins.
Slight expansion upon setting.
Very basic AKA alkaline (high pH when mixed with water).
Released calcium ions from MTA may interact with phosphorus in tissue fluid to yield hydroxylapatite, which helps to explain the physicochemical basis for MTA’s successful clinical applications
As a root-end filling material MTA shows less leakage than other root-end filling materials, which means bacterial migration to the apex is diminished.
Treated area needs to be infection free when applying MTA, because an acidic environment will prevent MTA from setting.
Compressive strength develops over a period of 28 days, similar to Portland cement.
Strengths of more than 50 MPa are achieved when mixed in a powder-to-liquid ratio of more than 3 to 1.
Minimum Alex opening to vascularize a tooth?
1mm
Ferric Sulfate chemical reaction in pulp
Ferrous ➡️ Ferric
Fe II ➡️ Fe III + H2O
Pulpotomy treatment that is both antibacterial and hemostatic?
Sodium Hypochlorite
MTA works by?
Mineralization
Has alkaline pH, slow release of Ca ions, induces pulp cell proliferation, cytokine release, hard tissue formation (reparative dentin), and interface with dentin that resembles hydroxyapetite
What is the most important thing in a Cvek pulpotomy procedure?
A tightly sealed margin
Pulpectomy on a Primary Tooth.
When does the radiolucency resolve?
6 weeks
After trauma, when is the signs of pulp necrosis visible radiographically?
3 months (12 weeks) for a mild injury such as concussion.
2 years for lateral luxation and intrusion
What should you do with a 3mm pulp exposure that happened less than 6 hours ago?
CVEK pulpotomy
What technique is best for detecting pulp involvement in children?
Radiograph
Why don’t you inject local anesthetic into an abscess?
- Low PH renders the anesthesia ineffective
2. Spread on infection
Can gutta percha be placed in a person with a Latex Allergy?
Yes, but do not go past the apex
What is the minimum apex opening needed to vascularize a tooth?
1mm
What dental anomaly is pulp obliteration found?
Dental Dysplasia (1 and 2)
What is the difference between White MTA and Grey MTA?
Iron
There are two commercial forms of MTA, namely the grey and the white. The difference between the grey and the white materials is the presence of iron in the grey material, which makes up the phase tetracalcium alumino-ferrite. This phase is absent in white MTA.
What is a hallmark finding of irreversible pulpitis?
Spontaneous Pain
What is required for any IPT?
Intact Lamina Dura
Most common finding in a Permanent Central Incisor
Necrosis
Open Apex: PCO
What does NaOCL (Sodium Hypochlorite) do to pulp stumps?
Sterilization
What is the success rate on an IPT on a Primary Tooth
90-95%
3% Sodium Hypochlorite has what two properties in regards to a pulpotomy
- Antibacterial
2. Hemostatic
Signs for Non-Vital pulp therapy
Percussion Sensitivity
External Root Resorption
Interpulpal Calcifications
What cells are found in a immature dental pulp?
Mesenchyme Cells
How does Ferric Sulphate work?
Creates HEMOSIDERIN Complex
Hemosiderin or haemosiderin is an iron-storage complex. The breakdown of heme gives rise to biliverdin and iron.
The body then traps the released iron and stores it as hemosiderin in tissues.
Hemosiderin is also generated from the abnormal metabolic pathway of ferritin.
It is only found within cells (as opposed to circulating in blood) and appears to be a complex of ferritin, denatured ferritin and other material.
Cell Zones in Pulp
The pulp develops 4 regions from the periphery to the central pulp:
- Odontoblast layer
- lies next to the predentin and mature dentin. - Cell free zone
- (zone of Weil) which is rich in both capillaries and nerve networks. - Cell rich zone
- which contains fibroblasts and undifferentiated mesenchymal cells. - Pulp core
- which is in the center of the pulp chamber with many cells and an extensive vascular supply; except for its location, it is very similar to the cell-rich zone.
What monitors pains in the pulp?
The Plexus of Raschkow
There are two types of nerve fiber that mediate the sensation of pain:
A-FIBERS:
-Conduct rapid and sharp pain sensations and belong to the myelinated group.
-Mainly of the A-delta type, are preferentially located in the periphery of the pulp, where they are in close association with the odontoblasts and extend fibers to many but not all dentinal tubules.
C-FIBERS:
- Conduct dull aching pain and are thinner and unmyelinated.
- Typically terminate in the pulp tissue proper, either as free nerve endings or as branches around blood vessels.
Sensory nerve fibers that originate from inferior and superior alveolar nerves innervate the odontoblastic layer of the pulp cavity. These nerves enter the tooth through the apical foramen as myelinated nerve bundles. They branch to form the subodontoblastic nerve plexus of Raschkow which is separated from the odontoblasts by a cell-free zone of Weil, therefore this plexus lies between the cell free and cell rich zones of the pulp.
What cells are found in a normal healthy pulp?
Fibroblasts (the principal cell), Odontoblasts
Defense cells:
histiocytes, macrophage, granulocytes, mast cells and plasma cells.
