endo Flashcards
what is stochastic effects of radiation?
there is no threshold dose below which stochastic effects do not occur and that the probability of experiencing these effects is proportional to the dose of radiation absorbed
(EDTA) full name +MOA
[ ] EDTA and duration before final rinse with… (with [ ]) ?
disadv
Role of Chelating and Decalcifying Agents [EDTA]
Ethylenediamine Tetraacetic Acid
removal of smear layer + enlargement of dentinal tubule [inorganic components, leaves organic tissue intact- thus NaOCL is necessary]
17% EDTA-1minute then->final rinse-NaOCl
Concentration ranges from 0.5% to 5.25%, with a common concentration being 2.5% to decrease potential toxicity while maintaining tissue dissolving and antimicrobial activity.
> 10mins - excessive removal of periTub. + intratubular dentine
1 Smear Layer Removal: improving canal cleanliness.
2 Enhancing Irrigation: - increase the efficacy of irrigants in disinfecting the root canal system.
3 Prevent apical compaction of debris.
4 Facilitating Obturation: The removal of the smear layer and opening of tubules allow for better adaptation of obturation materials and potentially stronger bonding of sealers.
pARAchloroaniLINE [PCA]- what is it?So what?
now what mx?
formation of insoluble brownish precipitate when NaOCL and CHX are combined in RCS.
Interfere with seal of obturation.
Mx: by drying canal with paper points or using saline as intermediate irrigant
NaOCL mechanism of action
-mechanical fx
-chemical action… by breaking down…
Adv4x
Disadv
mechanical flushing of debri out of canal and dissolves vital and necrotic tissue by breaking down proteins into amino acids.
Adv - 1 Antimicrobial, 2 lubricant by mechanical flushing debri 3 inexpensive 4 easily available
Disadv- hight toxic- must avoid extrusion
main Aims of Access Cavity Preparation: 5x
1 Remove all caries and defective restorations.
2 Locate and gain direct access to all root canal orifices.
3 Debride the pulp chamber (remove chamber roof and all coronal pulp tissue)- outline form.
4 Conserve tooth structure
5 Creates straight line access of instruments to apical 1/3 of the root; instrumentation and disinfection+ reduce procedural errors
Objectives of Access Cavity Preparation:
Biological Objectives: 2x
Mechanical Objectives: 6x
Biological Objectives:
1aRemove all infected material and caries.
2b Facilitate a good coronal seal to guard against oral contaminants.
Mechanical Objectives:
1Locate the pulp chamber and root canal orifices.
2 Ensure ease of operation and convenience for the operator.
3 Create an ideal outline form: Include the whole pulp chamber, avoiding overextension to conserve tooth structure.
4 Remove the roof of the pulp chamber and pulp horns.
5 St line access + smooth and gradually flare canal walls for effective debris removal and instrument placement.
6 Avoid procedural errors - ledging, transportation and perforation.
Anticurvature Filing
vs
Circumferential
Filing
used during coronal flaring- preserve furcal wall
Selectively removes dentine on bulky wall
+protecting inner furcal wall and coronal to the curvature- prevent strip perforation
vs
file is placed and withdrawn in a directional
manner sequentially [m,b,d,l]- lower incisors
Smear LayerComposition… that accumulate on..
Contamination:
Importance of Removal Before Obturation:
2x
organic pulpal materials and inorganic dental debris that accumulate on radicular canal wall
Contaminated with bacteria and metabolic by-products.
1Prevents sealer contact with canal wall.
2Used as a substrate for sustained growth of any microorganisms still in the dental tubules.
zipping is …
zipping is procedural error with apical transportation in curved canal+ shape of the canal is altered at the apex [elbow-zip formation],
torsional fatigue dt… and ….
cyclic fatigue -….
binding of file to canal - breakage of file at the tip
didnt bind - keep rotating and break over time
Apical Transportation …
inadvertent redirection of the canal’s natural path to a new location on the external root surface,
a result of instrumenting beyond the natural terminus of the canal.
H-type files knwn as…
feature: ……angle of blade edge and … of flute makes it…
usage limitation: only cuts on …. and used for …
not suitable for …. actions bcz can cause instruments to …
primary use- 3x
risk 2x
Hedstrom Files
Features: wide angle of the blade edge
depth of the flute -> sharpest files.
Usage Limitation: Only cuts on withdrawal and is exclusively for filing; not suitable for reaming or rotating actions as these can cause instrument fracture.
Primary Uses:
Filing dentinal walls.
Differentiating canal paths in multi-rooted teeth on radiographs (used alongside K-files).
Removing gutta-percha during retreatment/post preparation.
Risks:
Thoughtless insertion can lead to apical ledging.
Excessive filing may result in mid-root perforation.
Gold Standard for Endodontic Obturation materials
list types of materials
Advantages first option: 5x PMRLtS
Gutta-Percha > silver pts
1 Plasticity: Adapts well to irregularities in prepared canals when compacted.
2 Manipulation: easy to handle and manipulate for complex obturation techniques.
3 Removability: Can be partially or totally removed from the canal for post placement or retreatment.
4 Low Toxicity and is nearly inert when in contact with connective tissue.
5 Sterilization: Self-sterilizing properties; does not support bacterial growth. Contaminated cones can be sterilized predictably with 1% or greater sodium hypochlorite for 1 minute.
Disadvantages: gp 3X
HOW TO OVERCOME?
1 Adhesion: Lacks adhesion to dentin.
2 Elasticity: Slight rebound effect, which may cause pulling away from canal walls.
3 Shrinkage: GP shrinks upon cooling.
Marked shrinkage when mixed w/- chloroform[solvent].
Sealer Use:
Purpose: Fills and seals gap between the GP cones and between GP and the canal wall.
reciprocal induction in tooth formation..
reciprocal induction IEE release GF to [dental papilla] pulp cells to dy/dx to odontoblast-> dentine-> +IEE chg to ameloblast->enamel
[enamel] Epithelial-mesenchymal [dentine] interactions core processes of tooth formation
pharmacological methods other than LA
rely on… medication to decrease…3x
eg..
Pre emptive analgesia 1hr prior to procedure
adjunctive medication to decrease anxiety and response to potentially painful stimuli
during tx and ensure have better experience.
Eg. inhalation Nitrous oxide, oral BZD (eg. Triazolam has fast onset and relatively short T1/2,
lipophilic in nature and can be given sublingually for rapid absorption)- adults/ iv sedation Midazolam
Trephination, ie…… by ….. and is [indicated or CI?] post pulpectomy
artificial fisulation by creating an opening through mucosa and bone is not useful and Contraindicated
MEDICATION POST OP ANALGESICS FOR ENDO
ibuprofen 400mg 4X/day. First dose taken
before loss of LA -> by the clock 6hrly -> PRN
If severe pain, take 650-1000mg of paracetamol b/n
doses of ibuprofen (synergistic effect)
If NSAID CI, PCM 1g 4x/day and 60mg codeine
3x diff dx of pain on biting- what method to test?
Tooth Slooth/Wedge test used to differentiate a cracked tooth from fractured cusp/ split tooth
1 Cracked tooth: no movement (Torabinejad: positive
pain on release of biting force)
2 Fractured cusp: will break off under slight pressure
with no further mobility
3 Split tooth: mobility that extends below the CEJ
Prevention of propagation of cracked tooth with 3X
Removal of pulpal symptoms with cracked tooth Happens when 3x
1Orthodontic band
2 occlusal adjst to remove occl forces
3 Provisional crown
1 Often cuspal protection provides relief
2 occl adjstmt
3 If necessary, pulp extirpation/ rct
root end surgery/apicectomy is ….grade tx VS ….GRADE in Re-RCT
retrograde vs orthograde in RE-RCT
blocked canal mx:
prevention:
Do not increase force on the file as it may lead to ledge formation or instrumentation separation
-Attempt negotiation with RC prep
Practice recapitulation between each successive enlarging instrument regardless of the C&S
technique (ie, taking a smaller file to correct WL to loosen accumulation debris followed by flushing
with 1-2ml of irrigant)
Avoid compaction of tissue at apical end
RC prep made of…. helps…
glycol, urea peroxide and EDTA in a special water-soluble base
helps remove calcifications and lubricates canal
ferrule effect: important to preserve…. and … to create…. for..
… -… mm +ve effect on … resistance.
thickness of dentinal walls…. mm [minimum]
incomplete vs complete lack
no coronal structure…mx by
Preserving sound coronal and radicular tooth structure to create a ferrule effect is crucial for longevity of restored teeth.
1.5- to 2-mm of ferrule has a positive effect
on fracture resistance. Residual dentinal walls are expected to be at least 1mm thick. An incomplete ferrule is considered to be a better
option than a complete lack of ferrule.
In teeth with no coronal structure orthodontic extrusion should be considered rather than surgical crown lengthening.
Biologic Width is
do not… to ….
This distance can be
corrected with
distance from the depth of the gingival sulcus to the crest of the bone (relatively constant 2.04 mm*) JE 0.97mm; CT attachment =1.07mm.
violate to prevent chronic inflammation, attachment loss, or bone loss, which is
one of the keys for tooth and dental
restoration longevity
crown lengthening/ gingivectomy or
orthodontic extrusion. * Schmidt et al 2013; JClinPerio
post characteristics 3x
Post diameter should be minimal and <1/3 of the root diameter
Tapered post prep prevents the risk of creating a step at the apical post space but may
predispose to wedging and root fracture
Parallel posts provide greater retention than tapered posts and do not wedge
Cause Extrusion in Endodontics 2x
s/s 2x + 1x
1 Forceful Expression: Usually involves sodium hypochlorite, Irrigants can penetrate periapicular tissues.
2 Needle Positioning: Can occur from wedging the needle in the canal or out a perforation.
Symptoms/Signs (S/S):
1 Pain:Sudden,prolonged,+ sharp pain/ discomfort
2 Swelling: Rapid, diffuse swelling following the incident.
3 Potentially life-threatening due to cytotoxicity.
Prevention extrusion:
1 Needle Placement+depth: Use loose placement of irrigating needle, short of WL+Rubber stop; x bind
2 Irrigation Technique: Employ careful irrigation with light pressure; m/m to Agitate irrigant. endoactivator hand held sonic / ultrasonic …
3 Equipment: Use a perforated needle with a side port and rounded tip to minimize risk.
4 CBCT if see IADN is near to apices of roots -lower7’s - consider to refer
Management (Mx) NaOL accident: 3
- Initial management to alleviate symptoms. Analgesics and possibly antibiotics.
2 Patient Reassurance
3 Follow-Up: Recall to observe and monitor the patient’s recovery. / kiv referral
Intraappointment Emergencies: Causative iatrogenic Factors6x and host factors4x
factors reduce flare up incidence 2x
post tx/ undected crack
- Irritants within the Pulp System: Bacteria and by-products/ Necrotic pulp tissue- Inadequate Debridement of the canal.// LEAKY TD
- Operator-Controlled (Iatrogenic) Factors: MIOE
2i Missed canals/complex RCS
2ii. IC medication not used b/n visits
2iii OCC-Hyperocclusion in the temporary restoration.
2iv Extrusion -bacteria BEYOND apex.
2v extrusion use of intra-canal irrigants/ medicaments[Nicolau syndrome-purplish discolouration]. - Host Factors Influencing Emergencies
Pain History: with preoperative pain are more likely to experience a flare-up.
PA Pathology initially
Tx History: Retreated teeth show a higher incidence of flare-ups.
Systemic Health: Patients with allergies report higher flare-up rates. - factors that reduce flare ups
Presence of a sinus tract decreases the incidence of flare-up.Lower incidence in mandibular teeth.
qs to ask to know emergency or not 8x
disrupt [qof life -daily activities]; duration -hrs or days; drugs taken-any relief; then ; location, onset, aggravating factors/reliefing factors; character [describe sharp, dull etc]; feverish/malaise?
manage this endo emergency:
pain reflief
clinical evaluation
tx revision
f/up and completion
education
-
Immediate Pain Relief:
- Prescribe appropriate analgesics to manage the pain. Non-steroidal anti-inflammatory drugs (NSAIDs), ibuprofen 400mg qds PRN//with pcm 1g -synergistic effect are usually effective but consider the patient’s medical history.
- If possible, see the patient as soon as possible for clinical evaluation.
-
Clinical Evaluation:
- Perform a thorough clinical examination including percussion, palpation, and mobility tests to assess the severity and extent of the inflammation or infection.
- Re-evaluate the tooth with radiographic examination to assess any changes since the last visit, such as signs of periapical radiopacity indicating extrusion/PARL
-REASSURANCE
-
Treatment Revision:
- Under appropriate local anesthesia- long acting marcaine, reopen the tooth to relieve pressure from gases/exudates accumulated inside the pulp chamber or canal.
- Carefully clean and irrigate the canal using sodium hypochlorite or another suitable irrigation solution to reduce microbial load. Use minimal instrumentation to avoid further irritation.
- If significant over-instrumentation or a procedural accident (like a perforation) is identified, address it accordingly with appropriate materials MTA.
- Apply an intracanal medicament with antimicrobial properties, such as calcium hydroxide, to help reduce inflammation and bacterial levels.
- Temporarily seal the tooth to prevent bacterial ingress.
-
Follow-up and Completion:
- Schedule a follow-up visit in a few days to reassess pain and inflammation. If the symptoms have subsided, proceed with the next steps of endodontic treatment, such as obturation (filling of the canal).
- Educate the patient on signs of worsening conditions and ensure she understands when to seek immediate care.
-
Patient Education and Prevention:
- Explain to the patient the importance of following post-operative instructions, including oral hygiene practices and avoiding chewing on the affected side to prevent further irritation or injury.
- Discuss the prognosis of the tooth and possible outcomes of the treatment to set realistic expectations.
INTERNAL INFLAMMATORY ROOT RESORPTION
alteration of Rdgphc… angle area is in …. rshlp…
vs EXTERNAL INFLAMMATORY ROOT RESORPTION
horizontal angle
constant relationship to pulp space
vs
with external resorption the
Rlucent area shift with diff angle of Xray taken
Pulp Obliteration Overview
Incidence: Common In: 4x
visible on radiographs as early as …
Appearance:… discoloration dt
Etiology:
1Teeth with an open apex (>0.7mm radiographically).
2 Teeth that have undergone extrusive/lateral luxation injuries and have been rigidly splinted.
Detection: Usually visible on radiographs as early as 3-12 months post-injury.
Yellowish-brown discoloration due to thickened and less translucent coronal dentine.
Etiology: not fully understood. Likely a consequence of nerve supply damage leading to uncontrolled reparative dentine production.
OR Blood clot formation in the pulp post-injury create a nidus for calcification if the pulp remains vital.
pcobliteration could be indicative of… in response to … resulting in…
pcobliteration could be indicative of a ADAPTIVE FUNCTION of the pulp to the restorative procedures resulting in diffuse calcification in root canal. - NO tx req
Nature of pulpitis and apical periodontitis in relation to protection of the host against microbial infection
Pulpitis: reversible (transient pain, healable), irreversible (persistent spontaneous pain, unprovoked , assoc necrosis).
pathophysiology:
Innate Immune Response: Increased blood flow (hyperemia) and immune cell infiltration-Inf response to caries/trauma
Pain Mechanism: Increased pressure within the tooth due to inflammation (low compliance system).
Necrosis: persistent infection, pulp death.
Innate immune response happens before adaptive immune response, signifying change from reversible to irreversible pulpitis if insult not removed, LATER apical periodontitis ensues.
Apical Periodontitis: Extension of infection from necrotic pulp INTO periapical tissue, + pdl, + ct +bone involvement.
Immune Response: macrophages, lymphocytes, cytokines, vascular permeability.; innate and adaptive immune system (cell mediated/humoral)
Infection Containment: prevent spread, localize infection-> lead to the formation of granulation tissue, abscesses, or cysts.
Neutrophils will release lysozymes to digest phagocytosed bacteria forming micro-abcesses.
various HOST immune responses to control microbial challenge and initiate healing.
9 Principles of Root Canal Instrumentation aimed at preventing and healing apical periodontitis:
1 Elimination of Infected Tissue
Purpose: Remove necrotic tissue, bacteria, and byproducts to reduce microbial load.
Outcome: Disrupts ecological balance, preventing reinfection.
2 Preservation of Tooth Structure
Goal: Conserve tooth structure while ensuring thorough debridement; REduce risk of #
Technique: Maintain optimal cervical flare to prevent file deflection and preserve root integrity.
3 Shaping for Disinfection
Design: Access cavity and canal shaping (tapered coronally) facilitate irrigant and medicament effectiveness.
Tools: Use of sodium hypochlorite, CHX, and ultrasonic agitation [acoustic microstreaming] for enhanced disinfection.
4 Elimination of Microbial Hideouts
-Remove potential bacterial niches like isthmuses, fins, and lateral canals.
5 Sufficient Apical Stop
Objective: Create a well-shaped canal that can be effectively obturated with a hermetic seal.
6 Prevention of Extrusion
Technique: Employ careful instrumentation to avoid pushing debris, irrigants, or medicaments beyond the apex.
Risks: Prevent foreign body reactions, cytotoxic effects, periapical hemorrhage,inf &delay in healing.
7 Accurate Working Length Determination
How?: Establish and confirm working length with apex locator and consistent measurement, Continuous assessment using rubber stops and electronic apex locators to ensure accurate preparation.
8 Aseptic Technique
Environment: Maintain sterile conditions throughout the procedure to prevent contamination.
9 Removal of Smear Layer
Importance: Critical for ensuring direct sealer contact with canal walls and effective obturation.
Method: Use ultrasonic activation and appropriate irrigants (17% EDTA followed by NaOCL; avoid mixing CHX and NaOCL due to precipitate PCA formation).
Calcium hydroxide has been used successfully in root canal therapy for many years. However, it can cause serious damage if it is inadvertently displaced into surrounding vital structures, resulting in
in thrombosis if displaced into blood vessels, damaging connective tissue, and causing skin necrosis.
These adverse reactions are known as Nicolau Syndrome (NS).
E. Faecalis -> ….lesion bcz can ….. and bind to …..
persistent lesion
bcz can invade dentinal tubules and bind to dentine, reinfecting canal at later stage
biofilm are 6x
1 diverse bacterial communities attached to tooth surfaces , 2enclosed in extracellular matrix, EPS, of polymers from host and bacterial origin
3 initial stage is H bond and VDW forces–> 4covalent bond and ionic interactions
5 EPS- makes it ineffective for antimicrobial abx penetration, 6have slow growing microorganism , less effective to antimicrobials too
RCT Success in Teeth with Periapical Lesions 86% vs Without pre-op PARL 96% success - paper [yr]
(Sjogren et al 1990)
hydrodynamic theory is related to dentine hypersensitivity, which is a ….. arising from .3..[eg].
Three types of nerve fibers are found within dentin, ….
In this theory by Brannstorm, the fluid movement caused by stimuli is thought to stimulate…
sharp, transient pain
[3] stimuli exposure eg thermal,tactile, chemical or evaporative, are transmitted to the pulp surface due to the movement of fluid within open dentinal tubules.
including A-delta, A-beta, and C-fibers.
the myelinated, small A-delta fibers, which transmit the sensation of a localized, sharp pain to the brain.
Odontoblasts are located subadjacent to ….and are responsible for ….
to predentin
for synthesizing the dentine matrix and controlling dentine mineralization.
Factors Affecting RCT Success in tooth without PARL vs with.
1iii % success rate, type bacteria -eg, biofilm
2 Host -iii
3 Anatomy 4x
4 Tx -2x
- Extent and Complexity of Infection
Teeth with periapical lesions (86% success) vs. without lesions (96% success). sJOGREN et al 1990
Bacterial Complexity: Mix of aerobic and anaerobic bacteria, e.g., E. Faecalis, which invade dentinal tubules and form resistant biofilms.
Challenge: Biofilms have EPS resistant to antimicrobial agents and mechanical removal. - Host Response
Inflammatory Response: Produces granulation tissue, abscesses, or cysts, complicating healing.
Neutralization: Inflammatory by-products can neutralize the effects of irrigants and medicaments.
Persistent Bacteria: Actinomyces israelii and Propionibacterium species grow in clusters, resisting phagocytosis and conventional RCT. - Anatomical Challenges
Complex Systems: Accessory/lateral canals, isthmuses, and fins may harbor residual bacteria-limited reach
Canal Changes: Periapical lesions may cause canal calcification[pulp stone/diff] and complicate cleaning, shaping, and filling.
RR: PARL may lead to RR and lost of apical stop.
Apex: >anaerobic , <affected by tx
Nearby IADN - risk of extrusion is higher - Treatment Difficulties
Sealing Difficulties
Disinfection Challenges: Increased bacterial load and complex microbial flora make adequate disinfection tough.
Nair 2006 causes of persistent Apical periodontitis include Mainly dt IntraR infection, extra radicular infection dt periapical actinomycosis, accumulation of endogenous cholesterol crystals, extruded materials -> FB reaction, true cystic lesions, and scar tissue healing at periapex
B. Influence of Coronary Restoration and Root Filling Quality
- Quality of Coronary Restoration
Microleakage Prevention: Essential for preventing bacterial re-entry and ensuring structural integrity.
Restoration Retention: Weaker without a post; bonding systems enhance retention, premature contact (high spot) increase risk of #, underfill plaque retention - Quality of Root Filling
Complete Filling: Ensures the canal space is densely filled, preventing bacterial colonization and flush to 2mm of Rgphc apex.
Apical Seal: GP inert+not support bacterial growth ; materials like ZOE-based sealers (e.g., Roth sealer) provide antimicrobial properties and enhanced sealing.
Filling Length: Must be adequate; underfilled canals leave space for contamination, overfilled can irritate periapical tissues.
Both coronal restoration and root filling are critical for preventing recontamination and promoting healing of periapical tissues.
Non-Surgical Root Canal Treatment (NSRCT)
Advantages:
Disadvantages:
1 High success rate.
2 Preserves the natural tooth.
3 Non-invasive relative to surgical options.
4 Cost-effective.
1May fail with complex canal anatomy or extensive periapical pathology.
Aesthetic Options Post-NSRCT 3x
Advantages:
disadv
for each option
Intracoronal Bleaching and Direct Restoration
Advantages: Conservative, cost-effective, simple, easier for retreatment.
Disadvantages: Not suitable for heavy occlusion, aesthetic limitations, potential color regression, difficulty in achieving ideal shade.
Intracoronal Bleaching and Full Ceramic Crown
Advantages: Best aesthetic outcome.
Disadvantages: Higher cost, more visits required, potential for color regression due to translucency.
Porcelain Fused to Metal (PFM) Crown
Advantages: Blocks discolored tooth effectively.
Disadvantages: Least conservative, more tooth preparation required, potential visibility of metal band with gum recession.
Surgical Endodontics (Apicoectomy)
Advantages: 2x
Disadvantages:6x
1 Directly addresses periapical pathology.
2 Useful for complex root canal anatomy, persistent periapical lesions, obstructions, or irregularities.
Extraction and Replacement Options
Advantages:
Disadvantages:
1 Completely removes the source of infection.
2 Provides a long-term solution with options like dental implants or bridges.
More invasive, higher cost, longer treatment duration.
Loss of a natural tooth, potential for bone loss over time if an implant is not placed.
Cvek’s root classification describes …stages
five stages of root development:
I = < 1/2 root length,
II = 1/2 root length,
III = 2/3 root length,
IV = wide open apical foramen and nearly complete root length and,
V = closed apical foramen and completed root development.
RET
VS
Apexification in which Cvek RClassification
RET Stage 1-3-short root, thin canal walls and wide open apex
Apexification Stage 4
RCT Stage 5 enough thickness and strength
Impact of “Blood Supply” and “Infection” on
Outcome “Infection necrosis” versus “Regeneration/Repair”,
importance
fx
effect
Blood Supply: Vital for healing+regeneration after trauma.
Function: Supplies essential nutrients and immune cells.
Revascularization: Critical for root development and dentinal wall thickening in immature teeth with open apical foramina.
Effect: Intact blood supply increases the likelihood of successful regeneration and repair.
Infection
Impact: Negatively affects healing outcomes; can lead to pulpal necrosis and prevent natural repair.
Mechanism: Inflammatory resorption due to the immune response; destruction of tooth structures.
Pathway: Open apical foramina in immature teeth facilitate bacterial entry. Outcome - Infection Necrosis
Infection Necrosis:
Condition: Presence of bacteria leads to poor regeneration prospects and likely necrosis.
Consequences: Bacterial byproducts cause inflammatory responses, resulting in apical periodontitis and tooth structure destruction.
Regeneration/Repair:
Condition: Tooth remains free of infection and retains or regains blood supply.
Treatment Approaches: Pulp capping or partial pulpotomy to maintain vitality; use of regenerative endodontic treatment (RET) and apexification in more severe cases.
Cvek’s Classification:
Stage 1-3: Suitable for RET due to short root, thin canal walls, and wide open apex.
Stage 4-5: Suitable for apical MTA plug and RCT filling due to adequate wall thickness and strength.
Key Strategies: Preservation of blood supply and prevention of infection are critical for successful healing.
Management: Prompt and appropriate treatment to maintain or restore tooth vitality and prevent infection, enhancing regeneration over necrosis.
Likely Causes of Persistent Endodontic Lesion
1 Failure to completely remove infected tissue-debride/ inadequately disinfect the canal.
2 Bacteria: E. faecalis resistance to intracanal medications.
3 Missed Canals or Complex Anatomy features like isthmuses, fins, lateral canals. //C-shape and Dens evaginatus more common in Chinese races - also linked to increase in complex RCT mx
Indicators: Sensitivity to temperature changes suggesting missed anatomy.
4Procedural Errors
Types: Perforation, broken instruments, ledging.
Consequence: Complicates cleaning and shaping (C+S).
5 Poor Quality of Root Filling
Problems: Gaps, voids, improper length of filling.
Specifics: Inadequate apical seal if gutta-percha is removed excessively for post space.
6 Coronal Leakage
Issue: Defective crown margins or temporary cement dissolution leading to re-entry of bacteria.
7 Crack or Fracture
Cause: Undetected microcracks or fractures; potentially caused by excessive force during obturation.
Diagnosis: Check for narrow discharging sinus tract, perform periodontal probing, wedge test, Fiber Optic Transillumination (FOTI), and radiographs.
8 Secondary Infection
Cause: Recontamination from new decay, defective restorations, or periodontal issues.
9 Extraradicular Infection
Examples: Periapical actinomycosis or infection secondary to a periapical cyst.
Manifestation: Requires surgical intervention if there is the development of granulation tissue, abscesses, or cysts.
10 True Cystic Lesions
Characteristic: Self-sustaining and independent from the root canal system.
Class IV Cvek Root Development and Traumatized Tooth Outcomes
Root Development:
Blood Supply:
Pulpal Response:
- Root Maturity and Healing Response
Root Development: Near-complete with an open apex.
Blood Supply: Enhanced vascularity due to the open apex, promoting revascularization and healing.
Pulpal Response: Potential for new vital tissue ingrowth, leading to ongoing root development and apex closure. - Healing Potential
Regeneration Capabilities: Higher in immature teeth due to active stem cells and the ability to form a dentinal bridge.
Tx Response: Successful IPC or partial pulpotomy can enable continued development and maturation. - Structural Integrity:Thicker and stronger, providing structural support and resistance against bacterial invasion.
4 Susceptibility to Infection: Lower in Class IV compared to earlier stages; natural defenses more established. - Treatment Implications for Trauma
Regenerative Treatment Suitability: Limited potential for further development with regenerative endodontic therapy (RET); not ideal for Class IV.
Preferred Management: Likely involves conventional MTA apical plug placement rather than RET.
Objective: Disinfect canal, prevent reinfection, preserve tooth structure and achieve an apical barrier. - Comparison to Mature Teeth
Mature Teeth: Almost always require RCT following trauma due to higher likelihood of infection necrosis.
Initiation of Treatment: RCT is typically indicated within 2 weeks of trauma for mature roots.
open apex provides an ideal condition for …., also lead to the continuation of …, increasing the tooth’s long-term … compared to matured apex (closed apex).
revascularization and apexogenesis
root development
prognosis
Root Fracture (RF) - Impact by Location
and mx
1 Coronal Third:
Challenges: High risk of pulpal necrosis, difficulty in stabilization; splint 4 months, monitor healing,
Management: Potential extraction or removal of the coronal fragment, followed by RCT of the apical portion, and either crown lengthening or orthodontic extrusion if # at ging crevice occurs-IADT.
2 Middle Third:
Prognosis: Generally favorable.
Management: Proper alignment and stabilization, potential root canal treatment, and restoration aimed at balancing functional and aesthetic outcomes.
3Apical Third:
Prognosis: Best among the three.
Management: Minimal intervention often required; reposition and stabilize the coronal segment, splint for 4 weeks, perform RCT if pulp necrosis develops up to line of #.
Crown-Root Fracture (C-R) - Impact by Depth
1 Supragingival Fractures:
Prognosis: Favorable if restorable without periodontal surgery.
Management: Full-coverage crowns after assessing if pulp is exposed and the structural integrity is adequate.
2 Subgingival Fractures:
Prognosis: Varies; moderate to poor if extensive periodontal procedures like crown lengthening or orthodontic extrusion are required.
Management: Removal of subgingival fragments, possible gingivectomy/crwn lengthening, RCT followed by orthodontic extrusion or post-retained crown, or root submergence with future implant plans.//xn
key aspects of
Biofilms in Endodontic Infections
Definition:
Types of Biofilms
composition
endure period of …. leading to … infection
EPS fx 4x
…biofilm
sequelae of…
location
which bacteria -
tx dependant on association with..
Structured communities of bacterial cells enclosed in an extracellular matrix (EPS) found attached to dentinal walls or within necrotic tissues.
1 Intraradicular Biofilms
Composition: Diverse bacterial communities.
-Anaerobic, with some facultative (e.g., Lactobacilli) or microaerophilic species consume oxygen, low 02 lvl allows obligate anaerobes [fusobacterium] to predominate.
-Endure periods of nutrient deprivation, leading to persistent infections.
Function of EPS: Mediates adhesion, provides stability, facilitates nutrient acquisition, and protects against host defenses and antimicrobials, facilitate genetic exchanges, quorum sensing- peptides, and pathogenic synergism, which enhance the collective virulence of the community
2 Extraradicular Biofilms
Sequelae of intraradicular biofilm infection.
Location: Extend into periapical tissues.
Propionibacterium, actinomyces israeli, fusobacterium nucleatum, E. faecalis
Tx Dependent: Linked to intraradicular infection; treatable with conventional RCT (e.g., acute apical abscesses).
Independent: Requires endodontic surgery (e.g., true cystic lesions).
Function of EPS: 9x
1Mediates adhesion,
2provides stability,
3 facilitates nutrient acquisition,
4 retains water and maintains- highly hydrated micro-environment surrounding biofilm and
5protects against host defenses and antimicrobials VS planktonic - free-floating bacteria.
EPS matrix and the close proximity of cells within the biofilm
6 facilitate genetic exchanges,
7quorum sensing -G+ve Competence stimulating peptides [csp] induce competence in S. mutans, and
9 pathogenic synergism, which enhance the collective virulence of the community
Extraradicular biofilms name of bacteria 4x EaiFP
E. faecalis, , actinomyces israeli, fusobacterium nucleatum; Propionibacterium
Non-Surgical Endodontic Treatment:
Biological 1iii and Mechanical Principles5x
Biological Principles
1 Remove inflamed or infected pulp tissues + reduction of microbial loads using-
1a via Chemomechanical Preparation: irrigants placement is enhanced to kill bacteria,
disrupt biofilms, and dissolve organic tissue (NaOCl), EDTA and chlorhexidine for its long-lasting effects.
Intracanal Medicaments:
1b Create hostile environment for bacteria by altering pH- Calcium hydroxide, which neutralizes acidic conditions and disrupts biofilm integrity.
1c Prevent reinfection and facilitate effective apical seal with GP+sealer, minimizing bacterial and toxin displacement into periapical tissues.
Mechanical Principles
1Aseptic Technique:preventing recontamination; RDI and adhering to strict disinfection protocols.
2Effective Cleaning and Shaping:
appropriate cervical flaring +correct working length without overextension to prevent apical extrusion of materials.
3Creation of Tapered Canal Shape:
Purpose: Facilitate flow and action of irrigants, reaching all areas of the canal system.
Benefits: Improves irrigant efficacy, prevents file deflection, preserves tooth structure, and maintains cervical root integrity.
4Adjunctive Therapies:
Example: Ultrasonic irrigation to enhance biofilm disruption through acoustic streaming, increasing irrigant penetration and efficacy.
5Achieving a hermetic seal with the root canal filling to eliminate residual bacterial habitats and resists dislodgement during subsequent coronal restoration.
6 coronal seal
CaOH benefits as an effective intracanal medication dt
but it does not..
It can be introduced into the canal in various forms, such as a
1 antimicrobial properties, which are attributed to its
2 high alkaline pH12.5 .This high pH helps
3 inhibit microbial growth eg anaerobic bacteria that favor acidic environment.
4 aids in dissolving necrotic tissue remnants and bacteria, as well as their byproducts.
BUT does not reduce interappointment pain-than those with CcS.
1 dry powder, 2 a paste mixed with a liquid[saline/water], or as a 3 injected as proprietary paste, and is effectively placed using a lentulo spiral/Kfile-anticlockwise placement.
Step-back Technique involves…to create ….
vs
Crown-down Technique focuses on
sequentially using larger files at increasing distances from the working length to create a tapered canal shape
creating coronal flare to reduce the contact of the files with the canal walls as they reach the apical third.
criteria for evaluating the success of cleaning and shaping procedures in endodontics? Need to edit ans
1 Canal Preparation: continuously tapered funnel, maintaining the original shape of the canal and keeping the apical foramen in its original size and position.
2 Canal Cleanliness: “glassy smooth” walls, indicating thorough debridement. The presence of clean dentinal shavings and the clear color of irrigant can be indicators of cleanliness.
3 Apical Enlargement: 3sizes beyond first file to bind apically, so irrigants can reach the apical portion of the root, which is essential for effective cleaning and bacterial reduction.
4 Apical Patency: prevent loss of working length and to avoid packing the apical portion with tissue, dentin debris, and bacteria.
5 Instrumentation Technique: Knowledge of chosen technique [crown down] to minimize procedural errors and respect the tooth’s anatomy.
6 Elimination of Etiology: While complete debridement of the canal is virtually impossible due to anatomical complexities, the goal is to significantly reduce irritants causing infection.
7 Ultrasonic Cleaning: enhance the effectiveness of irrigants through acoustic microstreaming, which agitates the irrigant and improves cleaning efficacy.
8 Obturation: Hermetic seal
9 Coronal Seal: prevent recontamination of the canal
objectives of temporization in endodontic treatment are as follows: 4x
eg 3x
removal with
1To seal the tooth coronally, preventing the ingress of oral fluids and bacteria, as well as the egress of intracanal medicaments.
2 To protect the tooth structure until the final restoration is placed.
3 To allow for ease of placement and removal of the temporary restoration.
4 To satisfy esthetics, but prioritize providing a seal over appearance.
premixed cements like Cavit,
reinforced zinc oxide-eugenol cements such as IRM, glass ionomer cements
Removal= a high-speed bur can be used with care to avoid damage to the access opening or ultrasonic tip
Enlarging the cervical portion of the canal before performing RCT is important for several reasons: 6x
1 Facilitating Instrumentation: easier insertion and manipulation of endodontic instruments within the canal.Esp with curved or narrow canals.
2 Reducing Procedural Errors: Pre-enlargement helps to minimize the risk of procedural errors such as canal transportation, ledging, or zipping, especially in curved canals. It allows for a more gradual and controlled approach to shaping the apical portion of the canal.
3 Preventing Instrument Fracture: By enlarging the cervical portion, the stress on endodontic instruments is reduced, decreasing the likelihood of instrument fracture due to torsional forces or cyclic fatigue
4 Enhancing Debridement: facilitating the removal of the smear layer and organic debris.
5 Optimizing Obturation: to accommodate obturation techniques such as lateral compaction of gutta-percha, which requires space for spreader penetration and to achieve an adequate apical seal.
6 Improving Irrigation: A larger cervical opening enhances the ability to irrigate the canal effectively. Adequate irrigation is crucial for removing debris, necrotic tissue, and bacteria from the canal system.
Situations that necessitate the enlargement of the cervical portion include the
1 presence of calcifications or obstructions,
2 the need to straighten the initial canal path to improve access to the apical portion, and
3 when dealing with complex canal anatomy that requires improved visibility and access for complete cleaning and shaping.
To determine the appropriate size of the master apical file, follow these steps:
1 Initial Canal Exploration: Begin with smaller K files to gauge the canal size, shape, and configuration.
2 Working Length:which is the length at which the final apical file will be placed during the preparation.
3 Successive larger files into the canal until slight binding is encountered at the corrected working length =master apical file.
This is also starting point for the step-back preparation. The degree of enlargement depends on the canal size and curvature.
Recapitulation: Recapitulate between each instrument by reaming with the master apical file or a smaller instrument to minimize packing of debris and loss of length.
irregular canals, such as ..6x.
we have various techniques and instruments are employed to adapt to the unique anatomy.
1round, 2oval, 3hourglass, 44bowling-pin, 5kidney-bean, or 6ribbon-shaped cross-sections,
various 6x techniques and instruments are employed to adapt to the unique anatomy
-eg 1round, 2oval, 3hourglass, 44bowling-pin, 5kidney-bean, or 6ribbon-shaped cross-sections.
1 Circumferential Filing: This technique involves placing the file into the canal and withdrawing it in a directional manner sequentially against the mesial, distal, buccal, and lingual walls. Useful for larger canals that are not round, allowing for more uniform contact with the canal walls.
2 Anti-Curvature Filing: This method focuses on filing away from the danger zones where the canal is closest to the external root surface. It helps to prevent ledging and transportation in canals with shapes like hourglass or kidney-bean.
3Watching-winding:Reciprocating clockwise+ anti-clockwise rotation
4 REaming is clockwise cutting rotation
5 Nickel Titanium Rotary Preparation: Nickel titanium instruments are superelastic and can adapt to the irregular shapes of canals. They are particularly effective in maintaining the original canal path while enlarging and shaping canals with complex anatomy.
Crown-Down Technique: This technique removes coronal interferences first, providing coronal taper and facilitating the subsequent preparation of the apical portion. It is useful for canals with irregular shapes as it allows for a gradual approach to shaping the canal from the coronal to the apical end.
6 Combination Technique: This approach combines several techniques, such as coronal flaring, nickel titanium rotary preparation to address the complexities of irregular canal shapes.
Step-back Process:
Use the file one size larger than the master apical file and shorten it by 0.5 or 1.0 mm increments from the previous file length, creating a flared, tapering preparation.
7x minimize preparation errors in small curved canals, the following steps should be taken:
1 Initial Canal Exploration: Use smaller files[#6/8/10/15] to explore the canal and understand its size, shape, and configuration.Avoiding aggressive instrumentation.
This helps to confirm the presence of a canal and to establish a glide path.
2.Working Length Determination: Once patency is confirmed, determine the WL radiographically to understand the extent of the curvature or constriction.
3 st line access- Coronal Preflaring with hand instruments/Gates Glidden drills to facilitate the placement of larger working length files. This reduces the stress on the files in the apical region and minimizes the risk of canal transportation.
4 Use of Irrigants and Lubricants: Always manipulate files in a canal filled with an irrigant[u/sonic] or lubricant to reduce friction and prevent file breakage.
5 Gradual Apical Enlargement: using sequentially larger files. This helps in maintaining the original shape of the canal and avoiding over-enlargement.
6 Precurve files/check flutes/Nickel-titanium [limited 1-5x use only// 1x if calcified canal ]
7 In small curved canals, limit the enlargement to minimize the potential for transportation.
8 Recapitulation: Recapitulate after each instrument by taking a small file to the corrected working length and flushing the canal with an irrigant. This helps in loosening debris+avoiding packing of material apically.
9 Anti-Curvature Filing: preserve the integrity of the canal walls, especially in areas close to the furcation, to prevent stripping perforations.
Manual Instrumentation: adv/disadv
vs
Rotary NiTi Instruments:
Advantages: Allows for tactile feedback, which can be crucial in detecting canal irregularities and maintaining control in severely curved canals. It is cost-effective and does not require motor.
Disadvantages: Time-consuming, requires significant manual dexterity, and there is a higher risk of procedural errors such as canal transportation or zipping. It may also be less effective in creating a uniformly shaped canal.
Advantages: Efficient at canal shaping, reducing operator fatigue and treatment time. They are flexible and can negotiate curved canals more easily than stainless steel files. They also produce more consistent canal shapes.
Disadvantages: Risk of instrument fracture, especially if used beyond their fatigue limit. They may also be less effective in tactile sensation compared to manual files, which can lead to over-instrumentation.
physical properties of NiTi 5x
1superelasticity its flexibility and supermemory-more effective navigation of curved canals+improve overall shaping of the canal system vs SS files
->bend significantly without undergoing permanent deformation, which reduces the risk of canal transportation or zipping that can occur with less flexible materials
-> preservation of the original canal path, even in the presence of severe curvatures.
Resistance to cyclic fatigue
but careful monitoring of instrument use is essential to prevent instrument failure.
Temporization of extensively damaged teeth involves the use of a strong, durable filling material
that can provide …
For teeth without marginal ridges or with undermined cusps, … is recommended.
how to reduce #risk?
adequate thickness and good marginal adaptation to ensure a marginal seal.
a high-strength glass ionomer cement
Reducing the height of undermined cusps well out of occlusion reduces the risk of fracture/ orthodontic band cemented onto the tooth can strengthen the tooth against fracture.
Prevention of Ni-Ti File Separation: 6x
1 Frequent Inspection: Examine each instrument before use for signs of wear, distortion, or dull cutting flutes. Replace files as needed.
2 Proper Use: Follow the manufacturer’s guidelines for use, including the recommended speed and torque settings. Avoid forcing the file into the canal.
3 Lubrication: Continually lubricate the canal with irrigant or a lubricant to reduce friction and the risk of file separation.
4 Coronal Pre-Flaring: to reduce stress on the files during instrumentation.
5 Glide Path Creation: Create a glide path with small stainless steel files to allow Ni-Ti files to act as a passive pilot, reducing the risk of locking and torsional stress.
6 Automated Handpiece Systems: Use automated handpiece systems with low torque control motors, especially if inexperienced, to prevent over-stressing the files.
Causes of Ni-Ti File Separation: 4x
1 Cyclic Fatigue: Repeated use of Ni-Ti files in curved canals can lead to cyclic fatigue, weakening the metal structure over time->separation.
2 Torsional Stress: If the tip of a Ni-Ti file becomes locked in the canal while the handpiece continues to rotate, torsional stress accumulates, potentially causing the file to separate at the tip.
3 lack precoronal flaring
4 Improper Use:-applying excessive force, or selecting an inappropriately sized file for the canal or attempting to straighten a bent file.
Understanding of “Root Canal Working Length” in Endodontic Treatment:
Definition: distance from
Purpose:
Definition: Distance from a coronal reference point to the point C+S + obturation terminates usually 1.0mm from the radiographic apex, ideally at the apical constriction.
Purpose: Ensures avoiding overextension or underfilling RCT.
Techniques for Determining Working Length
1 Electronic Apex Locators (EALs)
Function: Measure electrical resistance to identify the apical foramen position.
Advantages: High accuracy, effective even in fluid-filled canals, simplifies measurements.
2 Radiographic Methods
Procedure: Use of pre-operative and working length radiographs with a small file in the canal.
Advantages: Visual confirmation of file position relative to apex; enhanced by digital radiography.
Combination Approach
Strategy: Employ both EALs and radiographic methods to verify and adjust working length.
Implications of Accurate Working Length Determination
Effective Cleaning and Shaping: Ensures complete debridement, reducing reinfection risk.
Prevention of Apical Extrusion: Avoids over-instrumentation that could lead to periapical tissue damage.
Optimal Filling: Allows for appropriate compaction and sealing of filling material, preventing microleakage.
Preservation of Periapical Tissues: Maintains tissue integrity to aid healing and prevent new infections.
Reduction in Treatment Failure: reduces procedural errors like ledging or perforation.
non-staining calcium silicate cements eg
vs staining calcium silicate cements
biodentine and NeoMTA
vs ProProot MTA discoloration as early as 3 months
after placement, and may continue to increase for up to two years.
Discuss the clinical and radiographic signs and symptoms of the periodontic – endodontic lesion according to the Simon, Glick and Frank 1972 classification.
-3x; aetiology +the pathways of communication/hw it spread
1 primary endodontic lesions, 2 primary periodontal lesions, and 3 combined lesions.
Primary Endodontic Lesions: = initiated by pulpal pathology leading to 2* periodontal involvement. Clinically, symptoms may include pain, sensitivity to hot or cold, and sometimes swelling. Radiographically, periapical radiolucencies are observed, indicating the endodontic origin of the disease. The periodontal involvement arises 2* to the spread of infection from the RCS to the periodontium through the apical foramen or accessory canals.
Primary Periodontal Lesions: These originate in the periodontium and may secondarily affect the pulp, RARELY HAPPENS. Clinically, present with signs of periodontal disease such as pocket formation, bleeding on probing, and attachment loss. Radiographically, there is evidence of alveolar bone loss not confined to the apex but rather affecting the lateral aspects of the root. Widen PDL SPACES; lost lamina dura. The pulp becomes involved if the periodontal disease is so advanced that it exposes the apical root to the oral environment or through the dentinal tubules.
Combined Lesions: Initially, these lesions start independently within the pulp and periodontium but eventually merge. Clinically, combined symptoms of endodontic and periodontal diseases are present, such as pain, deep pockets, sinus tract and mobility; furcation. Radiographically, features include both periapical radiolucencies and extensive bone loss along the root surface.Spread via both apical foramen and accessory canals. The microbial content in the root canals and the periodontal pockets can influence the severity of the lesion, and host factors such as immune response play a significant role in the progression of these combined lesions.
trismus width of mouth opening -mm
mild trismus as 20–30 mm interincisal opening,
moderate as 10–20 mm and
severe as less than 10 mm.
normal opening of mouth
Normal range: 40-60 mm,
averaging 35-55 mm (about the width of three fingers). M>F
Gender differences: M>F greater mouth opening.
Causes of Trismus: 7x
1 Infection:
Dental origin: Dental caries, severe periodontal disease, infections around lower third molar.
Non-dental origin: Tonsil infections, salivary gland infections, brain infections, tetanus.
Management: Remove cause, prescribe antibiotics, jaw exercises post-infection.
2 Dental Treatment:
Oral surgery, especially lower molar extraction, and infection at injection site.
3 Trauma:
TMJ fractures causing pain and mechanical obstruction. Managed by fracture reduction and immobilization.
4 TMJ Disorders:
Displacement of joint disc causing clicking sounds and pain. Treated with painkillers and muscle relaxants.
5 Tumors & Cancers:
Rare, but can cause severe limitation. Includes oral submucous fibrosis from betel nut chewing, squamous cell carcinoma, nasopharyngeal carcinoma.
6 Radiotherapy:
Causes fibrosis of mouth muscles, limiting mouth opening.
Complications of trismus:
Therapies:
Affects communication, denture fitting, physical re-examination, oral hygiene, chewing, swallowing, and overall quality of life.
1Heat Therapy: Hot, moist towels on affected area.
2Analgesics: NSAIDs like ibuprofen.
3Soft Diet: Avoid hard foods.
4Muscle Relaxants: Benzodiazepines (e.g., diazepam) or orphenadrine citrate.
5Physical Therapy:
iActive Jaw Exercises:Move jaw left, right, wide open, and in circles.
iiPassive Stretching: use fingers to gently push jaw open, holding stretch.
