BDS2 Endodontics Flashcards
Provide a brief sequence of endodontic disease.
Bacteria invades the enamel of the tooth surface which then spreads into dentinal caries which allows the bacteria to leak into the pulpal chamber causing inflammatory changes in the pulp.
If the caries are removed at the early stages, this inflammation can be reversed
If it not removed, then the inflammatory process cannot be reversed and necrosis of the pulp tissue occurs.
These inflammatory changes then occur all down the root canal and we see destruction of PDL and loss of bone.
What is the purpose of obturation?
Filling of the root canal space to prevent ingress of bacteria and persistent bacteria
What fibres are stimulated by an Electric Pulp Test (EPT)?
Alpha fibres
What fibres are affected if the patient complains of a sharp pain?
Alpha fibres
What fibres are affected if the patient complains of a dull/aching pain?
C fibres
What can a grey discoloured tooth indicate?
Blood breakdown products within the tooth
What can a pink discoloured tooth indicate?
Resorptive process that is occurring within the tooth
What is the purpose of cavity liners?
Name 3 examples
Thermal protection of the pulp and to prevent bacteria from entering
Examples
-Calcium hydroxide - dycal
-Resin modified glass ionomers (RMGI)- vitrebond
-Zinc oxide eugenol (ZOE)
What is the effect of calcium hydroxide?
Bacteriocidal
High pH- stimulated fibroblasts (reparative dentine formation)
Stimulated recalficiation of demineralised dentine
Neutralises low pH from acidic restorative materials
What are the options for treating pulp damage?
Indirect pulp cap
Direct pulp cap
Partial pulpal removal- pulpotomy
Full pulpal removal- pulpectomy (progress to RCT)
What is tertiary dentine?
Formed in reaction to external stimuli (e.g. bacterial toxins, trauma, attrition)
It is deposited in proximity to the site of injury
Can be sub-categorised as reactionary dentine and reparative dentine
What is reactionary dentine?
Formed when the insult to the odontoblast is not severe and the odontoblastic layer survives
What is reparative dentine?
Formed when the insult is more severe with excessive damage to the odontoblastic layer
Pulpal stem cells are recruited and differentiate into odontoblast-like cells
Dentinal tubules are usually not present or continuous with those from secondary or reactionary dentine
What are the signs and symptoms of extrusion of sodium hypochlorite through the root apex?
Intense pain and marked swelling of the area, with bleeding into the root canal from periradicular tissues
How can extrusion of sodium hypochlorite through the root apex occur?
Why?
High pressure injection during irrigation
Injecting the irrigation too deep in the canal
Locking the syringe in the canal
Acute inflammatory reaction-which can be oedematous and/or haemorrhagic- leads to significant tissue necrosis
What is your immediate action if the sodium hypochlorite has perforated through the root apex?
Local anaesthesia for pain relief
Canals irrigated with saline
Reassure patient
Dress tooth with non-setting calcium hydroxide
How can you prevent sodium hypochlorite from perforating through the apex of a tooth?
Careful pre-operative radiograph assessment- ensure no open apices
Provide bib and eyewear
Rubber dam
Use chlorhexidine to test rubber dam seal
Ensure all syringes are labelled correctly
Do not wedge needle in canal
Stopped on the needle 2mm before working length
Fill syringe less- easier to handle
What 3 criteria must have been fulfilled before you obturate a tooth?
Asymptomatic
Canal must be dried
Full chemomechanical disinfection carried out
What is the function of a sealer in obturation?
To fill the space between the GP and the root canal wall & provide a tight seal
How do you assess obturation on a radiograph?
Correct length
Well compacted
All canals filled
No GP in the pulp chamber
What are the 3 Herbst-Schiller principles of endodontics?
Continuously tapering funnel shape
Keep apical constriction as small as possible
Maintain apical foramen position
Give 4 reasons for irrigation during endodontic treatment.
Chemomechanical disinfection
Removes smear layer
Organic and inorganic content is dissolved
Flushes out debris
Lubrication- reduces friction between instrument and dentine
What is ledermix?
Medicament that can be placed in canals or the pulp chamber
Antibiotic and anti-inflammatory properties
What are the clinical objectives of endodontic therapy?
Removing canal contents
Eliminating infection
What is the purpose of mechanical preparation?
Creates space to allow irrigating solution and medicaments to more effectively eliminate micro-organisms from the root canal
What are the stages in mechanical preparation?
Preparation of tooth
Access cavity preparation
Creating straight line access
Initial negotiation
Coronal flaring
Working length determination
Apical preparation
Why is sodium hypochlorite a good irrigant?
Potent antimicrobial activity
Dissolves pulp remnants and collagen
Dissolves necrotic and vital tissue
Helps disrupt smear layer by acting on organic component
Name 6 ideal properties of an irrigant.
Low cost
Reduction of friction
Non-Toxic
Non-Allergic
Killing of biofilm microbes
Dissolution of organic and inorganic matter
Does not react with other dental materials
