Download - Endodontic failures
endodontic failures endodontic failures and retreatmentand retreatment
Introdution• In different studies success rate ranges from 54
percent to 95 percent.
• The definition of success is ambiguous - stringent : radiographic and clinical normalcy - lenient : only clinical normalcy
Endodontic treatment outcome
• Healed: both clinical and radiographic presentations are normal• Healing: it’s a dynamic process, reduced radiolucency combined with normal clinical presentation• Disease: No change or increase in radiolucency, clinical
signs may or may not be present or vice versa
Evaluation of success
• Success or failures following endodontic therapy could be evaluated from combination of clinical, histopathological and radio graphical criteria.
Clinical evaluation for success
• No tenderness to percussion or palpation• Normal tooth mobility• No evidence of subjective discomfort• Tooth having normal form, function and
aesthetics• No sign of infection or swelling• No sinus tract or integrated periodontal disease• Minimal to no scarring or discoloration
Radiographic evaluation for success
• Normal or slightly thickened periodontal ligament space
• Reduction or elimination of previous rarefaction• No evidence of resorption• Normal lamina dura• A dense three dimensional obturation of canal
space
Histological evaluation for success
• Absence of inflammation • Regeneration of periodontal ligament fibers• Presence of osseous repair• Repair of cementum• Absence of resorption• Repair of previously resorbed areas
Causes of the endodontic failures
Bacteria somewhere in the root canal system Divided into local and systemic
Factors affecting success or failure of endodontic therapy
in every case• Diagnosis and the treatment planning• Radiographic interpretation• Anatomy of the tooth and root canal system• Debridement of the root canal space
Factors affecting success or failure of endodontic therapy
in every case• Quality and extent of apical seal• Quality of post endodontic restoration• Systemic health of the patient• Skill of the operator
Factors affecting success or failure of a particular case Factors
affecting success or failure of a particular case
• Pupal and Periodontal status• Size of periapical radioleucency• Canal anatomy • Crown and root fracture
Factors affecting success or failure of a particular case Factors
affecting success or failure of a particular case
• Iatrogenic errors• Extent and quality of the obturation• Quality of the post endodontic restoration• Time of post treatment evaluation
Local Factors causing endodontic failures
• Infection• Incomplete debridement of the root canal system• Excessive hemorrhage• Chemical irritants• Iatrogenic errors
Infection• infected and necrotic pulp tissue→main irritant to
the periapical tissues• The host parasite relationship 、 virulence of
microorganisms , ability of infected tissues to heal→influence the repair of the periapical tissues
• Endo success →debridement
Incomplete debridement of the root canal system
• Main objective of root canal therapy→complete elimination
of the microorganisms and their byproducts
• Poor debridement → residual microorganisms 、 byproducts and tissue debris → recolonize
Excessive hemorrhage• Extirpation of pulp and instrumentation beyond
periapical tissues• Local accumulation of the blood→mild
inflammation• Extravasated blood cells and fluid : foreign body
nidus for bacterial growth
Over instrumentation
• Instrumentation beyond apical foramen→PDL and alveolar bone trauma→the prognosis of endodontic treatment ↓
Chemical irritants
• Intracanal medicaments and irrigating solution →extruded in the periapical tissues→the
prognosis of endodontic treatment ↓• One should take care while Using medicaments to
avoid their periapical extrusion
Iatrogenic errors• Separated instruments—• Caused by improper or overuse of • instruments and forcing them in curved canals • Prognosis : no much affected in vital pulps poor in necrotic tissue.
Iatrogenic errors• Canal blockage and ledge formation—• Accumulation of dentin chips or tissue debris prevent the instruments to reach its full working length • Ledge formation—straight instruments in curved canals• These lead to bacteria & debris remained endo failure
Iatrogenic errors• Perforations—• Lack of knowledge of anatomy of the tooth, attention, misdirection of the instruments• Prognosis : location, time, perforation seal and
size• Poor prognosis remaining infected tissue
Iatrogenic errors• Incompletely filled teeth—• Teeth filled more than 2mm short of apex• Several studies shown :• poor prognosis—underfillings with necrotic
pulps • Overfilling of root canals—• Overfilling extending ≧ 2mm beyond • radiographic apex• Continuous irritation of the periapical • tissues endo failure
Iatrogenic errors• Anatomic factors—• Such as : overly curved canals, calcifications, • numerous lateral and accessory canals,• bifurcations, C or S shaped canals• Problems in cleaning and shaping & • incomplete filling of root canals • endodontic failure
Iatrogenic errors• Root fractures—• Partial or complete fractures of roots• Prognosis of teeth :• vertical root is poor than horizontal fractures• Traumatic occlusion –• Cause endo failures because of its effect on • periodontium
Systemic factors causing endodontic failures
• Nutritional deficiencies
• Diabetes mellitus• Renal failure• Blood dyscrasias• Hormonal imbalance
• Autoimmune disorders• Opportunistic
infections• Aging• Long term steroid
therapy
Endodontic retreatment
Before going/performing Case selection Prognosis ,Contraindications and problems Steps
Before going to endodontic retreatment
• when should Treatment be considered• Patient’s needs• Strategic importance of the tooth• Periodontal evaluation of the tooth• Chair time & cost
Before performing to endodontic retreatment
• May to prevent the potential disease• Remove/remade extensive coronal restoration• Technical problems• May not achieve better results• Filling materials have to be removed• Prognosis could be poorer• Patient might be more apprehensive
Case selection• Careful history • Anatomy of root canal , canal curvature,
calcifications,unusual configurations• Quality of obturation• Iatrogenic complications• Cooperation of the patient
Factors affecting prognosis of endodontic treatment
• Periapical radiolucency• Quality of the obturation• Apical extension of the obturation material• Bacterial status• Observation period• Postendodontic coronal restoration• Iatrogenic complication
Contraindications of endodontic retreatment
• Unfavorable root anatomy• Untreatable root resorptions or perforations• Root or bifurcation caries• Insufficient crown/root ratio
Problems of endodontic retreatment
• Unpredictable result• Frustration• Cost factor• Time consuming
Steps of Retreatment1. Coronal disassembly2. Establish access to root canal system3. Remove canal obstructions4. Establish patency5. Thorough cleaning, shaping and obturation of
the canal
1. Coronal Disassembly• Removal of existing
coronal restoration• Access made through
coronal restoration
Advantages of gaining access through original restoration:a. Facilitate rubber dam
placementb. Maintaining form,
function and aestheticsc. Reducing the cost of replacement
Disadvantages of retaining a restoration:
a. Reduce visibility and accessibility
b. Increased risks of irreparable errors
c. Increased risks of microbial infection if crown margins are poorly adapted
Advice:Remove the existing restorationEspecially: poor marginal adaptation, secondary cariesPlace temporary crown to maintain form, function and aesthetics.
2. Establish Access to Root Canal System
Teeth restored with post and core:1.Post and core need to be removed for gaining access to root canal system2.Post and core can be perforated to gain access
Posts can be removed by:
1. Weakening retention of posts by use of ultrasonic vibration.2. Forceful pulling of posts but it increases the risk
of root fracture3. Removing posts with the help of special pliers
using post removal systems
Post Removal System(PRS)
Post Removal System(PRS)
• 5 various designed trephines• Corresponding taps(microtubular tap)• Torque bar• Transmetal bur• Rubber bumpers• Extracting plier
1-Transmental bur Effeciently dooming of the post head
2-Add lubricant
• EX: RC Prep• Be placed on the post head to further facilitate the
machining process
3-Trephine bur Use the largest bur to machine down the coronal 2-3 mm of the post.
4-Rubber bumper inserted on the tab & pushed on the occlusal
surface. Act as a cushion, distribute the loads and
protect thetooth during the removal procedure.
5-Microtubular tap• Inserted against the post head. • Screwed it into post with counter clockwise
direction and strongly engage the post.
Post removal plier• Mount the post removal plier on tubular tap• Ultrasonic instrument using/torque bar inserting
plier
Tubular tap
Rubber bumper
Screw knob
Ultrasonic instrument
1 -Nonsurgical Removal of Posts Broken Instruments - YouTube_x264.mp4
Post removal plier
Removing Canal Obstructions and
Establishing Patency
Silver Point Removal A- Microsurgical forceps
Silver point removalB-Ultrasonic
Siver point removalC- Using Hedstroem files(H-files)
Silver Point Removal
E- Post removal system kit.D- Instrument removal system(IRS).
Gutta-Percha Removal• The relative difficulty in removing gutta-percha is
influenced by some factors of canal system: Length Diameter Curvature Internal configuration
• Progressive Manner : gutta-percha is best removed from canal in
progressive manner to prevent its extrusion periapically
Gutta-Percha Removal• Coronal portion of gutta-percha should always be
explored by Gates-Gliddens to:Quickly : Remove gutta-percha quicklySolvent : Provide space for solventsConvenience : Improve convenience form
• Gutta-percha can be removed by using:SolventsHand instrumentsRotary instrumentsMicrodebrider
1. Solvents• GP is soluble in:
Chloroform : most effective but carcinogenic with high concentratin , excessive filling in pulp chamber is avoided
Methyl chloroformBenzeneXyleneEucalyptol oilHalothane
• GP dissolution should be supplemented by using hand instruments
2. Hand Instruments Used mainly in apical portion of the canal.• Hedstroem files• Hot endodontic instrument like Reamer or files
Poorly condenced GP can be pulled easily
3. Rotary Instruments•They are Safe to be used in straight canals Recently:•ProTaper universal systems
Consisting of file :D1 D2 D3500-700 rpm
Protaper universal system
• D1 : Remove filling from the coronal third• D2 : Remove filling from the middle third• D3 : Remove filling from appical third
Microdebriders A small files with 90 degrees bends Removing remaining gutta-percha on the sides
of canal walls
Pastes and Cement Soft setting pastes
Penetrated by endodontic instruments Hard setting cements
Softened by solvents: xylene, eucalyptol...... Then removed by files .
Ultrasonic devices
Separated Instruments and Foreign Objects
Coronal third – attempt retrieval Middle third – attempt retrieval or bypass Apical third – surgical treat
Separated Instruments and Foreign Objects
Attempt retrieval Mechanism → Stieglitz pliers, Massermann
extractor Vibration → Ultrasonics Accessibility → Modified Gates Glidden
bur Bypass
Reamers or files with copious irrigation Surgical treat
Apicoectomy
Ultrasonic
4-endo(instrument removal) - YouTube_x264.mp4
Instrument removal system (IRS)Can be used to remove the broken
files
microtube screw wedge
The beveled end of the microtube oriented toward the outer wall of the canal to “scoop up” the head of the broken file.
The introduction of the screw wedge which is rotated CCW to engage and displace the head of the file out the side window.
Completion of the Retreatment
Thorough cleaning, shaping and obturation The outcome of retreatment
Short-term: no pain and swelling Long-term: depended regaining canal patency &
obturation of the root canal system Retreatment is mostly associated with procedural
complication. Effective communication is required b/t dentist & patient.