tys shen ti endo

Question 1

what is the pathogenesis of necrotic pulp

Answer 1

• virulence factors of bacteria (LTA/ LPS) bind to TLR to activate immune response
• innate immune response takes place during initial invasion of pulp dentine complex with microbial irritatns
• toll like receptors activate neutrophils, NK cells and macrophages which cause inflammation and phagocytosis
• incresaed outflow of dentinal fluid from dentinal tubules
• dentinal fluid contains immune cells which mount a pulpal defence before antigen enter pulp. fluids also dilute toxins and maintains a positive out pressure to prevent the ingress of microorganism
• upregulation and expression of pro inflammatory cytokines and chemokiines by odontoblasts at pulp dentine junction. some of these diffuse into pulp where they activate and mobilise immune cells

then start of ADAPTIVE IMMUNITY
- antigen presenting cells present antigen to T helper cells, activating adaptive immune response

• B cells also differentiate into plasma cells that promote antigen specific antibodies
• when bacteria invades tertiary dentine, accumulation of neutrophils that discharge ROS, NO, lysozymes and hence cause tissue damage, liquefactive necrosis, and microabscess formation
• microabscess coalesce to form localised abscess
• local increase in tissue pressure will compress on thin wall venules and reduce blood flow to pulp, then metabolic waste accumulate, ph decrease, local irritation and increase in vascular permeability
• edema and swelling will occur as pulp is low compliance system then decreased blood flow and local necrosis -> totl necrosis

FOR APICAL INVOLVEMENT
- when bacteria reaches apical region of root canal system, there will be inflam reactio and tissue damage to eliminate bacteria

• production of IgG against bacteria at apex, and bacteria attaches, activating complement, leading to vascular permeability and edema
• activated macrophages produce IL1B and t lymphocytes produce TNFB which recruit and activate osteoclast (RANK RANKL) -> bone resorption
• in early stages of apical periodontitis, osteoclasts are abundant and outperform osteoblsat, so net loss of bone tissue near exit of apical foramen

Question 2

how to decide whethe to do the rct or refer to endodontist

Answer 2

AAE came up with assessment form to aid practitioners in endodontic tx planning and to help with referral decisions

3 main categories to consider

1) tx considerations
- tooth position in arch (before first molar) bc 2nd and 3rd molars better managed by endodontist
- isolation
- canal and root morphology
- resorption present
- calcified canals
- extremely curved canals

2) patient
- complex MH, better to see in hospital setting
- hx of achieiving anesthesia

3) additional considerations
- complicated trauma hx

Question 3

correlation between endo and systemic disease

Answer 3

1) some systemic diseases might mimic endo pain/ PARL
- pain modulating conditions like fibromyalgia
- acute infection like maxillary sinusitis

2) systmeic diseases may accelerate pulpal pathosis or influence tx outcomes
- association of cvd & diabetes
- immunocompromised cant heal
- recnet MI and uncotrolled htn is contra for endo tx

3) conditions that endo infections may initiate, or contribute to an infection in a distant site

• endo can cause systemic problems because bacteria from endo infections can cause bacteremia, migrate to lymph nodes and fascial spaces

Question 4

difference between percussion and palpation tests

Answer 4

PERCUSSION
- indicates inflammation in PDL
- but inflamamtory changes in PDL are not always of pulpal origin, can be perio

PALPATION
- inflammation in periapical tissues into bone and mucosa in the apical region
- can determine how far the infalmmatory process has extended into the PA tissues

Question 5

evidence for efficacy of pulp sensibility tests

Answer 5

Seltzer 1963 found poor correlation between EPT, thermal tests and histo

• severity of pain only partially related to severity of disease
• currently, the mesaures are used to investigate pulp sensitivity via nervous system response but true measures of pulp VITALITY include pulse oximetry, laser doppler flowmetry, ultrasound
• plus got limitation because certain teeth cannot be tested since immature teeth lack fully developed A delta fibers, which are the ones responding to the tests, and testing is unreliable until full root maturation occurs

COLD TEST
- if carried out on full coverage crowns and resto, it is 86% accuracy
- cold test tends to be more effective on anterior teeth with thinner dentine than more insulated posterior teeth
- endo ice is 1,1,1,2 tetrafluoroethane