Endo I Final - 3 - INSTRUMENTATION, Irrigation & Intracanal Medicaments, OBTURATION

• Remove infected soft and hard tissue.
• Give disinfecting irrigants access to the apical canal space.
• Create space for the delivery of medicaments and subsequent obturation which will provide an apical seal.
• Retain the integrity of radicular structures.

• the distance between the reference point and the apical constriction (minor diameter).
• can be determined using electronic apex locators, radiographies, tactile sensation, paper points.

the distance between the reference point and the apical foramen (major diameter).

• K-Files: cutting in reaming or a push-and-pull filing motion
• Hedstrom-Files: cutting on pulling strokes. More aggressive than K-files. More prone to break.
• Reamer: have less spirals or flutes per unit length. Use a reaming action (half-turn, twist and pull).
• Broaches: remove pulp tissue from wide open root canals.

• File length (mm) (21,25,31)
• Tip size (aka D0) (mm): a “20” file means that the
• diameter of the tip is 0.20 mm
• Taper size (mm): .04 taper means for every one mm of length, the width increases by .04 mm (up to D16 = D0 + taper * 16)

• 08 grey
• 10 purple
• -----------
• First series
• 15 white
• 20 yellow
• 25 red
• 30 blue
• 35 green
• 40 black
• -----------
• Second series
• 45 white
• 50 yellow
• 55 red
• 60 blue
• 70 green
• 80 black

• Drive engine files
• Nickel titanium (Nitinol)
• Different tapers
• Different sizes
• Different cross section design.
• Huge marketing for general dentists

• 55% Nickel, 45% titanium.
• More flexible.
• Resistant to cyclic fatigue: permits this instruments to be used in a rotary hand piece.
• Shape memory (good or bad; may cause transportation).
• Alteration in the composition -> controlled shape memory -> more resistant to fracture

• A smooth radicular tunnel from the canal orifice to the physiologic terminus of the root canal (patency).
• Achieved when the file can passively pass from the orifice and follow the smooth canal walls uninterrupted to the terminus.

• #10, #15: up to PATENCY LENGTH w/ LUBRICATION
• #20, #25, #30, #35: up to WORKING LENGTH w/ LUBRICATION, IRRIGATION, RECAPITULATION (to patency) in between
• STEP BACK
• #40 1mm SHORT
• #45 2mm SHORT
• #50 3mm SHORT

accomplished by taking a small file to the working length to loosen accumulated debris and then flushing w/ 1 to 2 ml of irrigant.

PATENCY FILE + IRRIGATION

• Ledges
• Zipping
• Apical transportation
• Perforations
• Stripping
• File separation

An artificial irregularity created on the surface of the root canal wall that impedes the placement of instruments to the apex of an otherwise patent canal.

An elliptical shape that may be formed in the apical foramen during preparation of a curved canal when a file extends through the apical foramen and subsequently transports that outer wall; a procedural error that complicates cleaning and obturation.

Removal of canal wall structure on the outside curve in the apical half of the canal due to the tendency of files to restore themselves to their original linear shape during canal preparation.

A complete penetration of a root canal wall due to excessive lateral tooth structure removal during canal preparation; usually occurs in curved roots or roots with surface invaginations.

• Inadequate access.
• Excessive apical pressure during instrumentation.
• Insufficient use of lubricants or irrigation solutions.
• Deficient knowledge of RC anatomy.
• Sharp curvatures or anatomic ledges, increases the chances of instrument fracture.
• Possibly manufacturing defects. Limitations in physical properties.

• • Debris removal
• • Dissolve organic and inorganic material
• • Remove living & nonliving irritants (bacteria, yeasts, viruses & their metabolic byproducts)
• • Remove Smear Layer

• Contents:
• - Organic & Inorganic substances
• - Dentin particles
• - Fragments of Odontoblastic processes
• - Remnants of vital and necrotic pulp tissue
• - Bacterial components
• Why remove it?
• - Organic debris can be substrate for bacterial growth
• - Prevents sealer contact with canal wall permitting leakage

• Penetrate Dentinal Tubules
• Tissue dissolution
• Smear layer removal
• Antimicrobial Action
• Instrument Lubrication
• Non-toxic
• Non-staining
• No adverse effect on dentin
• Inexpensive

• ANTIBACTERIAL AGENTS
• 1. Sodium Hypochlorite (NaOCl)
• 2. Chlorhexidine (CHX)
• DECALCIFYING AGENTS
• 1. Ethylenediaminetetraacetic Acid (EDTA)
• COMBINATION POSSIBLE

• == BLEACH
• Endodontic irrigant of choice
• Used in a range of dilutions: 2.5% in pre-doctoral clinic
• Mechanism of Action: Free chlorine dissolves tissues by breaking down proteins into amino acids
• Advantages:
• Dissolves organic tissue (vital tissue, necrotic tissue, components of dentin & biofilms)
• Antimicrobial
• Lubricating
• Inexpensive and readily available
• Disadvantages:
• Inability to remove smear layer
• Inability to kill all bacteria
• HIGHLY TOXIC if extruded beyond the apex, causes extensive edema, severe pain, possible paresthesia
• Precautions:
• NOT indicated in open apices (young patients)
• Irrigating needle must be placed loosely in the canal

0.12% CHX

• Mechanism of Action: Cation in water; electrostatically binds to negatively charged surface of bacteria, damaging outer layers of the cell wall rendering it permeable
• Advantages:
• Antimicrobial activity similar to 5.25% NaOCl
• Substantivity (long term antimicrobial action)
• Low level toxicity
• Disadvantages:
• Inability to dissolve organic tissue
• Inability to remove smear layer
• Inability to kill all bacteria

• CAN'T be mixed!
• NaOCl + CHX = PCA ⇩ brown orangy precipitate
• Must rinse (with isopropyl alcohol) & dry canal between NaOCl & CHX

• Mechanism of Action: Chelator, removes inorganic ions from tooth structure, leaves organic tissue intact
• Advantages: Removal of inorganic portion of smear layer
• Disadvantages: Little to no antimicrobial effect

• NaOCl (Organic Component)
• EDTA (Inorganic Component)

• CHX analog + EDTA + “surface-active agent”
• Indications:
• Smear layer removal
• Antimicrobial
• Antibiofilm activity
• Disadvantages:
• Expensive
• No organic tissue dissolution

• Tissue dissolution Y – orgnanic N N N
• Smear layer removal N N Y – inorganic Y
• Antimicrobial Action Y/Not all Y/Not all N Y + antibiofilm
• Instrument Lubrication Y - - -
• Non-toxic N Y – low - -
• Inexpensive Y - - N

• Goal: Keep irrigants confined to within the canal
• 1. Take off needle tip and load disposable syringe
• 2. Replace needle and hold perpendicular to the floor. Flick syringe to knock excess air to the top of the syringe and extrude excess air into cotton roll so there is no air in the syringe
• 3. Measure and pre-bend needle to 1 mm short of your working length
• 4. Insert needle into the canal. Do NOT intrude further than bend in needle. If needle fits tightly before reaching the measurement withdraw slightly so that needle fits loosely and is not binding in canal.
• 5. Inject slowly, moving in an up and down motion. If excessive pressure is necessary, or needle becomes stuck in canal, STOP extruding irrigant immediately and remove needle from canal and adjust.
• 6. The canal should always be wet during treatment
• 7. The canal should be irrigated between each file during instrumentation
• 8. The canal should be dried at the completion of the treatment session with suction and paper points before placing intracanal medicaments.

• If inadvertently injected beyond the apex (patient feels immediate pain, bleeding in the canal):
• 1. Remove and empty the syringe immediately.
• 2. Reinsert irrigating needle as far as possible. Aspirate until as much fluid as possible is removed.
• 3. Insert an anesthetic needle into the canal as far as possible and inject ~1ml anesthetic solution.
• 4. Discuss continued treatment with an instructor.

• 1. Irrigate with NaOCl
• 2. Dry canal
• 3. Irrigate with alcohol
• 4. Dry canal
• 5. Irrigate with QMiX and leave it in canal
• 6. Fit point with QMiX in the canal
• 7. Take radiograph or leave QMiX for 1min in the canal
• 8. Dry canal with paper points
• 9. Continue with obturation

• Interim appointment dressings
• Decrease bacterial count and prevent regrowth
• Render canal contents inert
• Reduce inter-appointment pain

• Advantages:
• Inhibits microbial growth in canals
• Dissolves tissue remnants
• Dissolves bacteria & bacterial byproducts (LPS)
• Must be present in canals for at least 1 week to have above effects!
• Forms: Powder or paste
• Precautions: Toxic; must be confined to the canals

• Ca(OH)2 should fill entire canal space
• Must be touching walls and tissue to work
• 1. Pre-measure tip and move stopper 1 mm short of working length
• 2. Pre-extrude on the bench to ensure flow and pressure necessary
• 3. Place the tip passively, yet as apical as possible
• 4. If resistance is encountered, move the syringe more coronally
• 5. Tip should NOT bind against canal walls
• 6. Extrude slowly while backing the tip out slowly and smoothly
• 7. Fill entirety of canal to level of the orifice
• 8. Place a small amount of cotton over the Ca(OH)2 and temporize.

• fill and seal a cleaned and shaped root canal using root canal sealer and core filling material
• ■ Reduce coronal leakage
• ■ Reduce bacterial contamination
• ■ Seal the apex from periapical fluids
• ■ Trap the residual irritants in the canal

• – Persistent symptoms
• – Severe symptomatic apical periodontitis
• – Acute Abscess
• – Persistent exudate in canal
• – Treatment or Patient Management concerns
• Presence of Bacteria in the Root Canal System at the time of Obturation has a Negative Impact on Long-term Prognosis

• Length: Reach the full working length of the canals
• Taper: reflect the shape of the final instrumented canals
• Density: homogenous and without voids

The main apical opening of the root canal

• The area of the apical foramen where the walls are
• furthest apart

• The area of the apical foramen where the walls are closest together
• – Typically 0.5 – 1 mm interior to the Major Diameter

from reference point to Major Diameter

from reference point to Minor Diameter

• Easily introduced into the canal
• Seal the canal laterally and apically
• Not shrink after insertion
• Be impervious to moisture
• Be bactericidal or at least discourage bacterial growth
• Be radiopaque
• Not stain the tooth structure
• Be sterile or easily sterilized
• Be easily removed from the root canal system

• Gutta Percha Cones (Core): Most commonly used core obturation material
• Sealer:
• - Zinc Oxide Eugenol most commonly used sealer.
• - Function: adjunctive to core material in creating water tight seal

• A trans-ionomer of polyisoprene (rubber)
• Advantages:
• – Plasticity
• – Easy to manipulate
• – Minimal toxicity
• – Radiopaque
• – Easy to remove with solvent or heat
• Disadvantages:
• – Lack of adhesion to dentin
• – Shrinkage upon cooling

• Standard
• ■ Follows ISO tip size specifications with the same color coding as files
• ■ Available in multiple standard tapers (0.02, 0.04, 0.06)
• Non-standardized (Conventional):
• ■ Labeled by tip, body
• ■ XF, FF, F, MF, FM, M, L, XL

• Exhibits tackiness when mixed
• Hermetic seal
• Radiopaque
• No shrinkage on setting
• No staining of tooth structure
• Bacteriostatic
• Sufficient working time
• Tissue tolerant
• Soluble in a common solvent to remove

• Advantages:
• – Long history of successful use
• – Antimicrobial activity
• – Slow setting time
• – Resorbs if extended beyond the apex
• Disadvantages:
• – Soluble
• – Nonadhesion
• – Toxic effects on host tissue

• Lateral Condensation
• Warm Vertical Compaction
• Solid core/carrier based Obturation
• Silver points (no longer utilized)
• Pastes (no longer utilized, except Zinc Oxide Eugneol for Pediatric teeth)

Sealer is placed in the canal followed by a fitted gutta-percha master point which is compacted apically and laterally by a tapering spreader to make room for additional accessory points.

• Final Irrigation
• ■ Sodium Hypochlorite
• ■ Dry Canals with Paper Points
• ■ Alcohol
• ■ Dry Canals with Paper Points
• ■ QMix

• Master Point Selection
• ■ Select Standardized Master Point/Master Cone:
• – 1-2 sizes larger than final instrumentation size
• ■ Fit Master Cone:
• – Must be fit to working length AND have “Tug-back”

• Slight frictional resistance of a master point to withdrawl when seated
• Indicates a relative degree of adaptation in 2 dimensions
• Dictated by surface area of point touching canal walls
• – Insufficient tug-back indicates apical portion of canal is not sealed, therefore, a larger point (with larger apical diameter and thereby surface area) is needed
• - also necessary to ensure point does not move beyond canal or coronal during obturation procedures

– Try a master point 1 size larger

– Try a master point 1 size larger

– Try a master point 1 size smaller

– Select the largest cone that was able to achieve working length, modify by trimming from the apical portion in 0.5 mm increments until tug back at the exact working length is achieved

Place Master Point that has Tug-back at Working Length in Canal and Mark (by crimping at reference point)

• Master Point Radiograph
• Radiograph must include full view of apex and beyond

Dry Canal with Paper Points

• Mix Sealer
• ■ Mix powder and liquid on a glass slab until smooth
• – No particles of powder should remain
• ■ Sealer should be about the consistency of yogurt
• – It should flow when inserted in the tooth
• – If too thick the sealer will not allow the gutta percha point to be seated properly

• Place Master Point
• ■ Take a small amount of sealer on a paper point and introduce the sealer into your canal to coat the canal walls
• ■ Grasp your master point at the crimped level and pick up a small amount of sealer onto the point
• ■ Slowly place the point to your work length; crimped portion of gutta percha must be at the reference point.

• Place Lateral Spreaders
• Lateral spreaders laterally and apically compact the gutta percha
• ■ Place and subsequently remove spreaders in series from largest to smallest with a twisting motion
• ■ Smallest lateral spreader should be within 1-2 mm of the working length

• Place Accessory Cone (non-standardized; placed 1 by 1)
• ■ Remove smallest finger spreader with twisting motion
• ■ Immediately place accessory cone coated with sealer in the space created by the finger spreader

• 7 & 8
• …until the spreader no longer penetrates into the canal
• ■ Accessory points are used from smallest to largest
• – Smallest accessory points utilized in apical region
• – Larger accessory points utilized in coronal region

Remove excess gutta percha & sealer with red hot plugger

Vertically compact coronal 1/3 of gutta percha with condensers

• Clean excess with alcohol soaked cotton or microbrush
• Chamber should be thoroughly cleaned with a solvent. Eucalyptol is in the dispensary. Do not let the
• solvent out of the tooth or the rubber dam will dissolve and soft tissue will be burned.

• Place Cotton & temporary filling
• Should have 3 mm of temporary material
• If time permits, place glass lonomer or composite,etc.(enter step 4 after obturation) rather than cavit or IRM.

• Final Radiograph
• Must have full view of apex and beyond
• No rubber dam

THE TOOTH RECEIVES A FINAL RESTORATION

• Excess Gutta-percha and sealer should be removed to the cementoenamel junction in anterior teeth and to the canal orifice in Posterior teeth.
• Length
• Taper
• Density
• Excess Material Removed
• Adequate Coronal Restoration

• Errors Should be corrected immediately
• Voids:
• – Remove gutta percha with hot pluggers to the level of the void, reapply sealer and repeat lateral condensation
• Under-fill:
• – Potential for unaddressed anatomy & persistent bacterial presence
• – Associated with increased risk of failure
• – Remove gutta percha, reinstrument
• Over-extension:
• – Obturating materials beyond the apex are irritants and affect healing
• – Histologically: increased inflammation and delayed or impaired healing
• – Increased post-obturation discomfort
• – Associated with increased risk of failure
• – Remove gutta percha prior to sealer setting